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Coker ZN, Troyanova-Wood M, Steelman ZA, Ibey BL, Bixler JN, Scully MO, Yakovlev VV. Brillouin microscopy monitors rapid responses in subcellular compartments. Photonix 2024; 5:9. [PMID: 38618142 PMCID: PMC11006764 DOI: 10.1186/s43074-024-00123-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/12/2024] [Accepted: 03/11/2024] [Indexed: 04/16/2024]
Abstract
Measurements and imaging of the mechanical response of biological cells are critical for understanding the mechanisms of many diseases, and for fundamental studies of energy, signal and force transduction. The recent emergence of Brillouin microscopy as a powerful non-contact, label-free way to non-invasively and non-destructively assess local viscoelastic properties provides an opportunity to expand the scope of biomechanical research to the sub-cellular level. Brillouin spectroscopy has recently been validated through static measurements of cell viscoelastic properties, however, fast (sub-second) measurements of sub-cellular cytomechanical changes have yet to be reported. In this report, we utilize a custom multimodal spectroscopy system to monitor for the very first time the rapid viscoelastic response of cells and subcellular structures to a short-duration electrical impulse. The cytomechanical response of three subcellular structures - cytoplasm, nucleoplasm, and nucleoli - were monitored, showing distinct mechanical changes despite an identical stimulus. Through this pioneering transformative study, we demonstrate the capability of Brillouin spectroscopy to measure rapid, real-time biomechanical changes within distinct subcellular compartments. Our results support the promising future of Brillouin spectroscopy within the broad scope of cellular biomechanics.
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Affiliation(s)
- Zachary N. Coker
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- SAIC, Fort Sam Houston, TX 78234 USA
| | | | - Zachary A. Steelman
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Bennett L. Ibey
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Joel N. Bixler
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Marlan O. Scully
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843 USA
| | - Vladislav V. Yakovlev
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843 USA
- Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, 101 Bizzell Street, College Station, TX 77843 USA
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Cantu JC, Barnes RA, Gamboa BM, Keister AS, Echchgadda I, Ibey BL. Effect of nanosecond pulsed electric fields (nsPEFs) on coronavirus survival. AMB Express 2023; 13:95. [PMID: 37689615 PMCID: PMC10492771 DOI: 10.1186/s13568-023-01601-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
Previous work demonstrated inactivation of influenza virus by GHz frequency electromagnetic fields. Despite theoretical and experimental results, the underlying mechanism driving this inactivation remains unknown. One hypothesis is that the electromagnetic field is causing damage to the virion membrane (and therefore changing spike protein orientation) rendering the virus unable to attach and infect host cells. Towards examining this hypothesis, our group employed nanosecond pulsed electric fields (nsPEFs) as a surrogate to radiofrequency (RF) exposure to enable exploration of dose response thresholds of electric field-induced viral membrane damage. In summary, Bovine coronavirus (BCoV) was exposed, in suspension, to mono and bipolar 600-ns pulsed electric fields (nsPEFs) at two amplitudes (12.5 and 25 kV/cm) and pulse numbers [0 (sham), 1, 5, 10, 100, and 1000] at a 1 Hz (Hz) repetition rate. The temperature rise immediately after exposure(s) was measured using thermocouples to differentiate effects of the electric field (E-field) and heating (i.e., the thermal gradient). Inactivation of BCoV was evaluated by infecting HRT-18G host cells and assessing differences in virus infectivity days after exposure. Our results show that 600 nsPEFs, both bipolar and monopolar, can reduce the infectivity of coronaviruses at various amplitudes, pulse numbers, and pulse polarity. Interestingly, we observed that bipolar exposures appeared to be more efficient at lower exposure intensities than monopolar pulses. Future work should focus on experiments to identify the mechanism underlying nsPEF-induced viral inactivation.
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Affiliation(s)
- Jody C Cantu
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, TX, USA
| | - Ronald A Barnes
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, USA
| | - Bryan M Gamboa
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, USA
| | - Allen S Keister
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, USA
| | - Ibtissam Echchgadda
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, USA.
| | - Bennett L Ibey
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, USA
- Air Force Office of Scientific Research, Air Force Research Laboratory, Arlington, VA, USA
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Kim V, Semenov I, Kiester AS, Keppler MA, Ibey BL, Bixler JN, Colunga Biancatelli RML, Pakhomov AG. Control of the Electroporation Efficiency of Nanosecond Pulses by Swinging the Electric Field Vector Direction. Int J Mol Sci 2023; 24:10921. [PMID: 37446096 DOI: 10.3390/ijms241310921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as "bipolar cancellation," enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing the electric field in the pairs (180° direction change) caused 2-fold (1 Hz) or 20-fold (833 kHz) weaker electroporation than the train of single nsEPs. Reducing the angle between pulse directions in the pairs weakened cancellation and replaced it with facilitation at angles <160° (1 Hz) and <130° (833 kHz). Facilitation plateaued at about three-fold stronger electroporation compared to single pulses at 90-100° angle for both nsEP frequencies. The profound dependence of the efficiency on the angle enables novel protocols for highly selective focal electroporation at one electrode in a three-electrode array while avoiding effects at the other electrodes. Nanosecond-resolution imaging of cell membrane potential was used to link the selectivity to charging kinetics by co- and counter-directional nsEPs.
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Affiliation(s)
- Vitalii Kim
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Allen S Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | | | - Bennett L Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Joel N Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Ruben M L Colunga Biancatelli
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
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Cantu JC, Butterworth JW, Mylacraine KS, Ibey BL, Gamboa BM, Johnson LR, Thomas RJ, Payne JA, Roach WP, Echchgadda I. Evaluation of inactivation of bovine coronavirus by low-level radiofrequency irradiation. Sci Rep 2023; 13:9800. [PMID: 37328590 PMCID: PMC10275941 DOI: 10.1038/s41598-023-36887-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
Inactivation of influenza A virus by radiofrequency (RF) energy exposure at levels near Institute of Electrical and Electronics Engineers (IEEE) safety thresholds has been reported. The authors hypothesized that this inactivation was through a structure-resonant energy transfer mechanism. If this hypothesis is confirmed, such a technology could be used to prevent transmission of virus in occupied public spaces where RF irradiation of surfaces could be performed at scale. The present study aims to both replicate and expand the previous work by investigating the neutralization of bovine coronavirus (BCoV), a surrogate of SARS-CoV-2, by RF radiation in 6-12 GHz range. Results showed an appreciable reduction in BCoV infectivity (up to 77%) due to RF exposure to certain frequencies, but failed to generate enough reduction to be considered clinically significant.
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Affiliation(s)
- Jody C Cantu
- General Dynamics Information Technology, JBSA Fort Sam Houston, TX, USA.
| | | | - Kevin S Mylacraine
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - Bryan M Gamboa
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - Leland R Johnson
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - Robert J Thomas
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - Jason A Payne
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
| | - William P Roach
- Air Force Office of Scientific Research, Air Force Research Laboratory, Arlington, VA, USA
| | - Ibtissam Echchgadda
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, TX, USA
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5
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Steelman ZA, Martens S, Tran J, Coker ZN, Sedelnikova A, Kiester AS, O’Connor SP, Ibey BL, Bixler JN. Rapid and precise tracking of water influx and efflux across cell membranes induced by a pulsed electric field. Biomed Opt Express 2023; 14:1894-1910. [PMID: 37206120 PMCID: PMC10191652 DOI: 10.1364/boe.485627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 05/21/2023]
Abstract
Quantitative measurements of water content within a single cell are notoriously difficult. In this work, we introduce a single-shot optical method for tracking the intracellular water content, by mass and volume, of a single cell at video rate. We utilize quantitative phase imaging and a priori knowledge of a spherical cellular geometry, leveraging a two-component mixture model to compute the intracellular water content. We apply this technique to study CHO-K1 cells responding to a pulsed electric field, which induces membrane permeabilization and rapid water influx or efflux depending upon the osmotic environment. The effects of mercury and gadolinium on water uptake in Jurkat cells following electropermeabilization are also examined.
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Affiliation(s)
| | - Stacey Martens
- Air Force Research Laboratory, JBSA Fort Sam Houston, Texas 78234, USA
| | - Jennifer Tran
- University of Wisconsin-Madison School of Pharmacy, 777 Highland Avenue, Madison, WI 53705, USA
| | | | | | - Allen S. Kiester
- Air Force Research Laboratory, JBSA Fort Sam Houston, Texas 78234, USA
| | | | - Bennett L. Ibey
- Air Force Research Laboratory, JBSA Fort Sam Houston, Texas 78234, USA
| | - Joel N. Bixler
- Air Force Research Laboratory, JBSA Fort Sam Houston, Texas 78234, USA
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6
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Echchgadda I, Cantu JC, Butterworth J, Gamboa B, Barnes R, Freeman DA, Ruhr FA, Williams WC, Johnson LR, Payne J, Thomas RJ, Roach WP, Ibey BL. Evaluation of Viral Inactivation on Dry Surface by High Peak Power Microwave (HPPM) Exposure. Bioelectromagnetics 2023; 44:5-16. [PMID: 36786477 DOI: 10.1002/bem.22435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 12/02/2022] [Accepted: 01/28/2023] [Indexed: 02/15/2023]
Abstract
Previous research has shown that virus infectivity can be dramatically reduced by radio frequency exposure in the gigahertz (GHz) frequency range. Given the worldwide SARS-CoV-2 pandemic, which has caused over 1 million deaths and has had a profound global economic impact, there is a need for a noninvasive technology that can reduce the transmission of virus among humans. RF is a potential wide area-of-effect viral decontamination technology that could be used in hospital rooms where patients are expelling virus, in grocery and convenience stores where local populations mix, and in first responder settings where rapid medical response spans many potentially infected locations within hours. In this study, we used bovine coronavirus (BCoV) as a surrogate of SARS-CoV-2 and exposed it to high peak power microwave (HPPM) pulses at four narrowband frequencies: 2.8, 5.6, 8.5, and 9.3 GHz. Exposures consisted of 2 µs pulses delivered at 500 Hz, with pulse counts varied by decades between 1 and 10,000. The peak field intensities (i.e. the instantaneous power density of each pulse) ranged between 0.6 and 6.5 MW/m2 , depending on the microwave frequency. The HPPM exposures were delivered to plastic coverslips containing BCoV dried on the surface. Hemagglutination (HA) and cytopathic effect analyses were performed 6 days after inoculation of host cells to assess viral infectivity. No change in viral infectivity was seen with increasing dose (pulse number) across the tested frequencies. Under all conditions tested, exposure did not reduce infectivity more than 1.0 log10. For the conditions studied, high peak power pulsed RF exposures in the 2-10 GHz range appear ineffective as a virucidal approach for hard surface decontamination. © 2023 Bioelectromagnetics Society.
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Affiliation(s)
- Ibtissam Echchgadda
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Jody C Cantu
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Joey Butterworth
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Bryan Gamboa
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Ronald Barnes
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - David A Freeman
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Francis A Ruhr
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Weston C Williams
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Leland R Johnson
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Jason Payne
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Robert J Thomas
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - William P Roach
- Air Force Office of Scientific Research, Air Force Research Laboratory, Arlington, Virginia, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
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Gudvangen E, Mangalanathan U, Semenov I, Kiester AS, Keppler MA, Ibey BL, Bixler JN, Pakhomov AG. Pulsed Electric Field Ablation of Esophageal Malignancies and Mitigating Damage to Smooth Muscle: An In Vitro Study. Int J Mol Sci 2023; 24:ijms24032854. [PMID: 36769172 PMCID: PMC9917603 DOI: 10.3390/ijms24032854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Cancer ablation therapies aim to be efficient while minimizing damage to healthy tissues. Nanosecond pulsed electric field (nsPEF) is a promising ablation modality because of its selectivity against certain cell types and reduced neuromuscular effects. We compared cell killing efficiency by PEF (100 pulses, 200 ns-10 µs duration, 10 Hz) in a panel of human esophageal cells (normal and pre-malignant epithelial and smooth muscle). Normal epithelial cells were less sensitive than the pre-malignant ones to unipolar PEF (15-20% higher LD50, p < 0.05). Smooth muscle cells (SMC) oriented randomly in the electric field were more sensitive, with 30-40% lower LD50 (p < 0.01). Trains of ten, 300-ns pulses at 10 kV/cm caused twofold weaker electroporative uptake of YO-PRO-1 dye in normal epithelial cells than in either pre-malignant cells or in SMC oriented perpendicularly to the field. Aligning SMC with the field reduced the dye uptake fourfold, along with a twofold reduction in Ca2+ transients. A 300-ns pulse induced a twofold smaller transmembrane potential in cells aligned with the field, making them less vulnerable to electroporation. We infer that damage to SMC from nsPEF ablation of esophageal malignancies can be minimized by applying the electric field parallel to the predominant SMC orientation.
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Affiliation(s)
- Emily Gudvangen
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Uma Mangalanathan
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Allen S. Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | | | - Bennett L. Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Joel N. Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
- Correspondence:
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Kim V, Semenov I, Kiester AS, Keppler MA, Ibey BL, Bixler JN, Pakhomov AG. Action spectra and mechanisms of (in) efficiency of bipolar electric pulses at electroporation. Bioelectrochemistry 2023; 149:108319. [PMID: 36375440 PMCID: PMC9729435 DOI: 10.1016/j.bioelechem.2022.108319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/19/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022]
Abstract
The reversal of the electric field direction inhibits various biological effects of nanosecond electric pulses (nsEP). This feature, known as "bipolar cancellation," enables interference targeting of nsEP bioeffects remotely from stimulating electrodes, for prospective applications such as precise cancer ablation and non-invasive deep brain stimulation. This study was undertaken to achieve the maximum cancellation of electroporation, by quantifying the impact of the pulse shape, duration, number, and repetition rate across a broad range of electric field strengths. Monolayers of endothelial cells (BPAE) were electroporated in a non-uniform electric field. Cell membrane permeabilization was quantified by YO-PRO-1 (YP) dye uptake and correlated to local electric field strength. For most conditions tested, adding an opposite polarity phase reduced YP uptake by 50-80 %. The strongest cancellation, which reduced YP uptake by 95-97 %, was accomplished by adding a 50 % second phase to 600-ns pulses delivered at a high repetition rate of 833 kHz. Strobe photography of nanosecond kinetics of membrane potential in single CHO cells revealed the temporal summation of polarization by individual unipolar nsEP applied at sub-MHz rate, leading to enhanced electroporation. In contrast, there was no summation for bipolar pulses, and increasing their repetition rate suppressed electroporation. These new findings are discussed in the context of bipolar cancellation mechanisms and remote focusing applications.
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Affiliation(s)
- Vitalii Kim
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Allen S Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | | | - Bennett L Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | - Joel N Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
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Hoff BW, Cohick ZW, Tilley BS, Luginsland JW, Revelli D, Cox J, Irshad H, Snider A, Arndt A, Ibey BL, Enderich DA, Thomas RJ, McConaha JW, Franzi MA, Roach WP, Shiffler DA. Observed Reductions in the Infectivity of Bioaerosols Containing Bovine Coronavirus Under Repetitively Pulsed RF Exposure. IEEE Trans Biomed Eng 2022; 70:640-649. [PMID: 35976820 DOI: 10.1109/tbme.2022.3199333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The purpose of the present study is to investigate the inactivation of bioaerosols containing Bovine Coronavirus, BCov, under repetitively pulsed radio frequency (RF) electromagnetic exposure. METHODS These experiments were performed in a waveguide containing a flowing aerosol stream and were limited to a single RF waveform: ∼2 μs square envelope, 5.6 GHz, 4.8 kHz repetition rate. Aerosol streams were exposed to RF electric field amplitudes in the range of 41.9 +/- 6.2 kV/m. Under laminar flow conditions, 75% of the total collected aerosol stream spends 0.85 seconds or less in the RF exposure region. RESULTS Application of the RF waveform changes mean survival rate of the aerosolized BCov by -0.58 decades (roughly a 74% reduction) and impacted the variance and standard deviation of the experimental results, with the RF exposure data showing an 800% increase in variance and 196% increase in standard deviation over the control results. Experimental results were compared to those from an analytic electromagnetic-heating inactivation model. CONCLUSION The comparison indicated the feasibility that the observed reduction in BCov survival rate might be due to a combination of thermal effects and non-thermal electric field effects. SIGNIFICANCE Developing better insight into the mechanisms of inactivation is important for understanding the potential limits of efficacy for this method. Additionally, these results contribute an important baseline for the impact of electromagnetic fields on aerosolized pathogens.
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10
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Echchgadda I, Cantu JC, Tolstykh GP, Butterworth JW, Payne JA, Ibey BL. Changes in the excitability of primary hippocampal neurons following exposure to 3.0 GHz radiofrequency electromagnetic fields. Sci Rep 2022; 12:3506. [PMID: 35241689 PMCID: PMC8894459 DOI: 10.1038/s41598-022-06914-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 02/04/2022] [Indexed: 12/23/2022] Open
Abstract
Exposures to radiofrequency electromagnetic fields (RF-EMFs, 100 kHz to 6 GHz) have been associated with both positive and negative effects on cognitive behavior. To elucidate the mechanism of RF-EMF interaction, a few studies have examined its impact on neuronal activity and synaptic plasticity. However, there is still a need for additional basic research that further our understanding of the underlying mechanisms of RF-EMFs on the neuronal system. The present study investigated changes in neuronal activity and synaptic transmission following a 60-min exposure to 3.0 GHz RF-EMF at a low dose (specific absorption rate (SAR) < 1 W/kg). We showed that RF-EMF exposure decreased the amplitude of action potential (AP), depolarized neuronal resting membrane potential (MP), and increased neuronal excitability and synaptic transmission in cultured primary hippocampal neurons (PHNs). The results show that RF-EMF exposure can alter neuronal activity and highlight that more investigations should be performed to fully explore the RF-EMF effects and mechanisms.
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Affiliation(s)
- Ibtissam Echchgadda
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA.
| | - Jody C Cantu
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA
| | - Gleb P Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA
| | - Joseph W Butterworth
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA
| | - Jason A Payne
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, 711Th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, 4141 Petroleum Road, San Antonio, TX, 78234, USA
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11
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Steelman ZA, Coker ZN, Kiester A, Noojin G, Ibey BL, Bixler JN. Quantitative phase microscopy monitors subcellular dynamics in single cells exposed to nanosecond pulsed electric fields. J Biophotonics 2021; 14:e202100125. [PMID: 34291579 DOI: 10.1002/jbio.202100125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/11/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
A substantial body of literature exists to study the dynamics of single cells exposed to short duration (<1 μs), high peak power (~1 MV/m) transient electric fields. Much of this research is limited to traditional fluorescence-based microscopy techniques, which introduce exogenous agents to the culture and are only sensitive to a single molecular target. Quantitative phase imaging (QPI) is a coherent imaging modality which uses optical path length as a label-free contrast mechanism, and has proven highly effective for the study of single-cell dynamics. In this work, we introduce QPI as a useful imaging tool for the study of cells undergoing cytoskeletal remodeling after nanosecond pulsed electric field (nsPEF) exposure. In particular, we use cell swelling, dry mass and disorder strength measurements derived from QPI phase images to monitor the cellular response to nsPEFs. We hope this demonstration of QPI's utility will lead to a further adoption of the technique for the study of directed energy bioeffects.
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Affiliation(s)
- Zachary A Steelman
- National Research Council Research Associateship Program, Washington, District of Columbia, USA
| | - Zachary N Coker
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas, USA
- SAIC, San Antonio, Texas, USA
| | - Allen Kiester
- 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | | | - Bennett L Ibey
- 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
| | - Joel N Bixler
- 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, JBSA Fort Sam Houston, San Antonio, Texas, USA
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12
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Steelman ZA, Sedelnikova A, Coker ZN, Kiester A, Noojin G, Ibey BL, Bixler JN. Visualizing bleb mass dynamics in single cells using quantitative phase microscopy. Appl Opt 2021; 60:G10-G18. [PMID: 34613190 DOI: 10.1364/ao.426147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Understanding biological responses to directed energy (DE) is critical to ensure the safety of personnel within the Department of Defense. At the Air Force Research Laboratory, we have developed or adapted advanced optical imaging systems that quantify biophysical responses to DE. One notable cellular response to DE exposure is the formation of blebs, or semi-spherical protrusions of the plasma membrane in living cells. In this work, we demonstrate the capacity of quantitative phase imaging (QPI) to both visualize and quantify the formation of membrane blebs following DE exposure. QPI is an interferometric imaging tool that uses optical path length as a label-free contrast mechanism and is sensitive to the non-aqueous mass density, or dry mass, of living cells. Blebs from both CHO-K1 and U937 cells were generated after exposure to a series of 600 ns, 21.2 kV/cm electric pulses. These blebs were visualized in real time, and their dry mass relative to the rest of the cell body was quantified as a function of time. It is our hope that this system will lead to an improved understanding of both DE-induced and apoptotic blebbing.
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13
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Tolstykh GP, Valdez CM, Montgomery ND, Cantu JC, Sedelnikova A, Ibey BL. Intrinsic properties of primary hippocampal neurons contribute to PIP 2 depletion during nsEP-induced physiological response. Bioelectrochemistry 2021; 142:107930. [PMID: 34450563 DOI: 10.1016/j.bioelechem.2021.107930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 08/03/2021] [Accepted: 08/10/2021] [Indexed: 12/23/2022]
Abstract
High-energy, short-duration electric pulses (EPs) are known to be effective in neuromodulation, but the biological mechanisms underlying this effect remain unclear. Recently, we discovered that nanosecond electric pulses (nsEPs) could initiate the phosphatidylinositol4,5-bisphosphate (PIP2) depletion in non-excitable cells identical to agonist-induced activation of the Gq11 coupled receptors. PIP2 is the precursor for multiple intracellular second messengers critically involved in the regulation of intracellular Ca2+ homeostasis and plasma membrane (PM) ion channels responsible for the control of neuronal excitability. In this paper we demonstrate a novel finding that five day in vitro (DIV5) primary hippocampal neurons (PHNs) undergo significantly higher PIP2 depletion after 7.5 kV/cm 600 ns EP exposure than DIV1 PHNs and day 1-5 (D1-D5) non-excitable Chinese hamster ovarian cells with muscarinic receptor 1 (CHO-hM1). Despite the age of development, the stronger 15 kV/cm 600 ns or longer 7.5 kV/cm 12 µs EP initiated profound PIP2 depletion in all cells studied, outlining damage of the cellular PM and electroporation. Therefore, the intrinsic properties of PHNs in concert with nanoporation explain the stronger neuronal response to nsEP at lower intensity exposures. PIP2 reduction in neurons could be a primary biological mechanism responsible for the stimulation or inhibition of neuronal tissues.
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Affiliation(s)
- Gleb P Tolstykh
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.
| | - Christopher M Valdez
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Noel D Montgomery
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Jody C Cantu
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | | | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
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14
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Kiester AS, Ibey BL, Coker ZN, Pakhomov AG, Bixler JN. Strobe photography mapping of cell membrane potential with nanosecond resolution. Bioelectrochemistry 2021; 142:107929. [PMID: 34438186 DOI: 10.1016/j.bioelechem.2021.107929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
The ability to directly observe membrane potential charging dynamics across a full microscopic field of view is vital for understanding interactions between a biological system and a given electrical stimulus. Accurate empirical knowledge of cell membrane electrodynamics will enable validation of fundamental hypotheses posited by the single shell model, which includes the degree of voltage change across a membrane and cellular sensitivity to external electric field non-uniformity and directionality. To this end, we have developed a high-speed strobe microscopy system with a time resolution of ~ 6 ns that allows us to acquire time-sequential data for temporally repeatable events (non-injurious electrostimulation). The imagery from this system allows for direct comparison of membrane voltage change to both computationally simulated external electric fields and time-dependent membrane charging models. Acquisition of a full microscope field of view enables the selection of data from multiple cell locations experiencing different electrical fields in a single image sequence for analysis. Using this system, more realistic membrane parameters can be estimated from living cells to better inform predictive models. As a proof of concept, we present evidence that within the range of membrane conductivity used in simulation literature, higher values are likely more valid.
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Affiliation(s)
- Allen S Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | - Bennett L Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | | | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Joel N Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA.
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Cantu JC, Tolstykh GP, Tarango M, Beier HT, Ibey BL. Caveolin-1 is Involved in Regulating the Biological Response of Cells to Nanosecond Pulsed Electric Fields. J Membr Biol 2021; 254:141-156. [PMID: 33427940 DOI: 10.1007/s00232-020-00160-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/18/2020] [Indexed: 01/20/2023]
Abstract
Nanosecond pulsed electric fields (nsPEFs) induce changes in the plasma membrane (PM), including PM permeabilization (termed nanoporation), allowing free passage of ions into the cell and, in certain cases, cell death. Recent studies from our laboratory show that the composition of the PM is a critical determinant of PM nanoporation. Thus, we hypothesized that the biological response to nsPEF exposure could be influenced by lipid microdomains, including caveolae, which are specialized invaginations of the PM that are enriched in cholesterol and contain aggregates of important cell signaling proteins, such as caveolin-1 (Cav1). Caveolae play a significant role in cellular signal transduction, including control of calcium influx and cell death by interaction of Cav1 with regulatory signaling proteins. Present results show that depletion of Cav1 increased the influx of calcium, while Cav1 overexpression produced the opposite effect. Additionally, Cav1 is known to bind and sequester important cell signaling proteins within caveolae, rendering the binding partners inactive. Imaging of the PM after nsPEF exposure showed localized depletion of PM Cav1 and results of co-immunoprecipitation studies showed dissociation of two critical Cav1 binding partners (transient receptor potential cation channel subfamily C1 (TRPC1) and inositol trisphosphate receptor (IP3R)) after exposure to nsPEFs. Release of TRPC1 and IP3R from Cav1 would activate downstream signaling cascades, including store-operated calcium entry, which could explain the influx in calcium after nsPEF exposure. Results of the current study establish a significant relationship between Cav1 and the activation of cell signaling pathways in response to nsPEFs.
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Affiliation(s)
- Jody C Cantu
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, Bldg. 3260, San Antonio, TX, 78234-2644, USA.
| | - Gleb P Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, Bldg. 3260, San Antonio, TX, 78234-2644, USA
| | - Melissa Tarango
- General Dynamics Information Technology, JBSA Fort Sam Houston, 4141 Petroleum Road, Bldg. 3260, San Antonio, TX, 78234-2644, USA
| | - Hope T Beier
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Optical Radiation Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, 78234, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX, 78234, USA
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Martens SL, Klein S, Barnes RA, TrejoSanchez P, Roth CC, Ibey BL. 600-ns pulsed electric fields affect inactivation and antibiotic susceptibilities of Escherichia coli and Lactobacillus acidophilus. AMB Express 2020; 10:55. [PMID: 32189137 PMCID: PMC7080936 DOI: 10.1186/s13568-020-00991-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/10/2020] [Indexed: 12/23/2022] Open
Abstract
Cell suspensions of Escherichia coli and Lactobacillus acidophilus were exposed to 600-ns pulsed electric fields (nsPEFs) at varying amplitudes (Low-13.5, Mid-18.5 or High-23.5 kV cm−1) and pulse numbers (0 (sham), 1, 5, 10, 100 or 1000) at a 1 hertz (Hz) repetition rate. The induced temperature rise generated at these exposure parameters, hereafter termed thermal gradient, was measured and applied independently to cell suspensions in order to differentiate inactivation triggered by electric field (E-field) from heating. Treated cell suspensions were plated and cellular inactivation was quantified by colony counts after a 24-hour (h) incubation period. Additionally, cells from both exposure conditions were incubated with various antibiotic-soaked discs to determine if nsPEF exposure would induce changes in antibiotic susceptibility. Results indicate that, for both species, the total delivered energy (amplitude, pulse number and pulse duration) determined the magnitude of cell inactivation. Specifically, for 18.5 and 23.5 kV cm−1 exposures, L. acidophilus was more sensitive to the inactivation effects of nsPEF than E. coli, however, for the 13.5 kV cm−1 exposures E. coli was more sensitive, suggesting that L. acidophilus may need to meet an E-field threshold before significant inactivation can occur. Results also indicate that antibiotic susceptibility was enhanced by multiple nsPEF exposures, as observed by increased zones of growth inhibition. Moreover, for both species, a temperature increase of ≤ 20 °C (89% of exposures) was not sufficient to significantly alter cell inactivation, whereas none of the thermal equivalent exposures were sufficient to change antibiotic susceptibility categories.
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17
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Tolstykh GP, Cantu JC, Tarango M, Ibey BL. Receptor- and store-operated mechanisms of calcium entry during the nanosecond electric pulse-induced cellular response. Biochim Biophys Acta Biomembr 2018; 1861:685-696. [PMID: 30552899 DOI: 10.1016/j.bbamem.2018.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 11/16/2022]
Abstract
Nanosecond electric pulses have been shown to open nanopores in the cell plasma membrane by fluorescent imaging of calcium uptake and fluorescent dyes, including propidium (Pr) iodide and YO-PRO-1 (YP1). Recently, we demonstrated that nsEPs also induce the phosphoinositide intracellular signaling cascade by phosphatidylinositol-4,5-bisphosphate (PIP2) depletion resulting in physiological responses similar to those observed following stimulation of Gq11-coupled receptors. In this paper, we explore the role of receptor- and store-operated calcium entry (ROCE/SOCE) mechanisms in the observed response of cells to nsEP. We show that addition of the ROCE/SOCE and transient receptor potential channel (TRPC) blocker gadolinium (Gd3+, 300 μM) slows PIP2 depletion following 1 and 20 nsEP exposures. Lipid rafts, regions of the plasma membrane rich in PIP2 and TRPC, are also disrupted by nsEP exposure suggesting that ROCE/SOCE mechanisms are likely impacted. Reducing the expression of stromal interaction molecule 1 (STIM1) protein, a key protein in ROCE and SOCE, in cells exposure to nsEP resulted in a reduction in induced intracellular calcium rise. Additionally, after exposure to 1 and 20 nsEPs (16.2 kV/cm, 5 Hz), intracellular calcium rises were significantly reduced by the addition of GD3+ and SKF-96365 (1-[2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl) propoxy] ethyl-1H-imidazole hydrochloride, 100 μM), a blocker of STIM1 interaction. However, using similar nsEP exposure parameters, SKF-96365 was less effective at reducing YP1 uptake compared to Gd3+. Thus, it is possible that SKF-96365 could block STIM1 interactions within the cell, while Gd3+ could acts on TRPC/nanopores from outside of the cell. Our results present evidence of nsEP induces ROCE and SOCE mechanisms and demonstrate that YP1 and Ca2+ cannot be used solely as markers of nsEP-induced nanoporation.
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Affiliation(s)
- Gleb P Tolstykh
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.
| | - Jody C Cantu
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Melissa Tarango
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
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18
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Beier HT, Roth CC, Bixler JN, Sedelnikova AV, Ibey BL. Visualization of Dynamic Sub-microsecond Changes in Membrane Potential. Biophys J 2018; 116:120-126. [PMID: 30579565 DOI: 10.1016/j.bpj.2018.11.3129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 11/08/2018] [Accepted: 11/20/2018] [Indexed: 02/07/2023] Open
Abstract
Direct observation of rapid membrane potential changes is critical to understand how complex neurological systems function. This knowledge is especially important when stimulation is achieved through an external stimulus meant to mimic a naturally occurring process. To enable exploration of this dynamic space, we developed an all-optical method for observing rapid changes in membrane potential at temporal resolutions of ∼25 ns. By applying a single 600-ns electric pulse, we observed sub-microsecond, continuous membrane charging and discharging dynamics. Close agreement between the acquired results and an analytical membrane-charging model validates the utility of this technique. This tool will deepen our understanding of the role of membrane potential dynamics in the regulation of many biological and chemical processes within living systems.
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Affiliation(s)
- Hope T Beier
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas.
| | - Caleb C Roth
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | - Joel N Bixler
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | | | - Bennett L Ibey
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
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19
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Thompson GL, Beier HT, Ibey BL. Tracking Lysosome Migration within Chinese Hamster Ovary (CHO) Cells Following Exposure to Nanosecond Pulsed Electric Fields. Bioengineering (Basel) 2018; 5:bioengineering5040103. [PMID: 30477132 PMCID: PMC6316806 DOI: 10.3390/bioengineering5040103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/02/2018] [Accepted: 11/18/2018] [Indexed: 11/16/2022] Open
Abstract
Above a threshold electric field strength, 600 ns-duration pulsed electric field (nsPEF) exposure substantially porates and permeabilizes cellular plasma membranes in aqueous solution to many small ions. Repetitive exposures increase permeabilization to calcium ions (Ca2+) in a dosage-dependent manner. Such exposure conditions can create relatively long-lived pores that reseal after passive lateral diffusion of lipids should have closed the pores. One explanation for eventual pore resealing is active membrane repair, and an ubiquitous repair mechanism in mammalian cells is lysosome exocytosis. A previous study shows that intracellular lysosome movement halts upon a 16.2 kV/cm, 600-ns PEF exposure of a single train of 20 pulses at 5 Hz. In that study, lysosome stagnation qualitatively correlates with the presence of Ca2+ in the extracellular solution and with microtubule collapse. The present study tests the hypothesis that limitation of nsPEF-induced Ca2+ influx and colloid osmotic cell swelling permits unabated lysosome translocation in exposed cells. The results indicate that the efforts used herein to preclude Ca2+ influx and colloid osmotic swelling following nsPEF exposure did not prevent attenuation of lysosome translocation. Intracellular lysosome movement is inhibited by nsPEF exposure(s) in the presence of PEG 300-containing solution or by 20 pulses of nsPEF in the presence of extracellular calcium. The only cases with no significant decreases in lysosome movement are the sham and exposure to a single nsPEF in Ca2+-free solution.
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Affiliation(s)
- Gary L Thompson
- Department of Chemical Engineering, Rowan University, Glassboro, NJ 08028, USA.
| | - Hope T Beier
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio-Fort Sam Houston, San Antonio, TX 78234, USA.
| | - Bennett L Ibey
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio-Fort Sam Houston, San Antonio, TX 78234, USA.
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Martens SL, Roth CC, Ibey BL. Nanosecond pulsed electric field exposure does not induce the unfolded protein response in adult human dermal fibroblasts. Bioelectromagnetics 2018; 39:491-499. [PMID: 29984845 DOI: 10.1002/bem.22131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/21/2018] [Indexed: 02/03/2023]
Abstract
Cell-circuit models have suggested that nanosecond pulsed electric fields (nsPEFs) can disrupt intracellular membranes including endoplasmic reticulum (ER), mitochondria, and/or nucleus thereby inducing intrinsic apoptotic pathways. Therefore, we hypothesized that the unfolded protein response (UPR) would be activated, due to the fluctuations of ionic concentrations, upon poration of the ER membrane. Quantitative real-time polymerase chain reaction was utilized to measure changes in messenger RNA (mRNA) expression of specific ER stress genes in adult human dermal fibroblast (HDFa) cells treated with tunicamycin (TM) (known ER stress inducer) and cells exposed to nsPEFs (100, 10-ns pulses at 150 kV/cm delivered at a repetition rate of 1 Hz). For HDFa cells, results showed time-dependent UPR activation to TM; however, when HDFa cells were exposed to nsPEFs, no significant changes in mRNA expression of ER stress genes, and/or caspase gene were observed. These results indicate that although cell death can be observed under these exposure parameters, it is most likely not initiated through activation of the UPR. Bioelectromagnetics. 2018;39:491-499, 2018. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Stacey L Martens
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | - Caleb C Roth
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | - Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
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21
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Valdez CM, Barnes RA, Roth CC, Moen EK, Throckmorton GA, Ibey BL. Asymmetrical bipolar nanosecond electric pulse widths modify bipolar cancellation. Sci Rep 2017; 7:16372. [PMID: 29180756 PMCID: PMC5703993 DOI: 10.1038/s41598-017-16142-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 11/03/2017] [Indexed: 12/20/2022] Open
Abstract
A bipolar (BP) nanosecond electric pulse (nsEP) exposure generates reduced calcium influx compared to a unipolar (UP) nsEP. This attenuated physiological response from a BP nsEP exposure is termed "bipolar cancellation" (BPC). The predominant BP nsEP parameters that induce BPC consist of a positive polarity (↑) front pulse followed by the delivery of a negative polarity (↓) back pulse of equal voltage and width; thereby the duration is twice a UP nsEP exposure. We tested these BPC parameters, and discovered that a BP nsEP with symmetrical pulse widths is not required to generate BPC. For example, our data revealed the physiological response initiated by a ↑900 nsEP exposure can be cancelled by a second pulse that is a third of its duration. However, we observed a complete loss of BPC from a ↑300 nsEP followed by a ↓900 nsEP exposure. Spatiotemporal analysis revealed these asymmetrical BP nsEP exposures generate distinct local YO-PRO®-1 uptake patterns across the plasma membrane. From these findings, we generated a conceptual model that suggests BPC is a phenomenon balanced by localized charging and discharging events across the membrane.
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Affiliation(s)
- Chris M Valdez
- National Research Council Research Associateship Program, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam Houston, Texas, 78234, USA
| | - Ronald A Barnes
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam Houston, Texas, 78234, USA
| | - Caleb C Roth
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam Houston, Texas, 78234, USA
| | - Erick K Moen
- Ming Hsieh Department of Electrical Engineering- Electrophysics, University of Southern California, 920 Bloom Walk, SSC, 502, Los Angeles, California, USA
| | - Graham A Throckmorton
- Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, Tennessee, 37235, USA
| | - Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Airman Systems Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam Houston, Texas, 78234, USA.
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Tolstykh GP, Olsovsky CA, Ibey BL, Beier HT. Ryanodine and IP 3 receptor-mediated calcium signaling play a pivotal role in neurological infrared laser modulation. Neurophotonics 2017; 4:025001. [PMID: 28413806 PMCID: PMC5381754 DOI: 10.1117/1.nph.4.2.025001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/20/2017] [Indexed: 05/13/2023]
Abstract
Pulsed infrared (IR) laser energy has been shown to modulate neurological activity through both stimulation and inhibition of action potentials. While the mechanism(s) behind this phenomenon is (are) not completely understood, certain hypotheses suggest that the rise in temperature from IR exposure could activate temperature- or pressure-sensitive ion channels or create pores in the cellular outer membrane, allowing an influx of typically plasma-membrane-impermeant ions. Studies using fluorescent intensity-based calcium ion ([Formula: see text]) sensitive dyes show changes in [Formula: see text] levels after various IR stimulation parameters, which suggests that [Formula: see text] may originate from the external solution. However, activation of intracellular signaling pathways has also been demonstrated, indicating a more complex mechanism of increasing intracellular [Formula: see text] concentration. We quantified the [Formula: see text] mobilization in terms of influx from the external solution and efflux from intracellular organelles using Fura-2 and a high-speed ratiometric imaging system that rapidly alternates the dye excitation wavelengths. Using nonexcitable Chinese hamster ovarian ([Formula: see text]) cells and neuroblastoma-glioma (NG108) cells, we demonstrate that intracellular [Formula: see text] receptors play an important role in the IR-induced [Formula: see text], with the [Formula: see text] response augmented by ryanodine receptors in excitable cells.
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Affiliation(s)
- Gleb P. Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, United States
- Address all correspondence to: Gleb P. Tolstykh, E-mail:
| | - Cory A. Olsovsky
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Bennett L. Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
| | - Hope T. Beier
- Air Force Research Laboratory, 711th Human Performance Wing, Airman System Directorate, Bioeffects Division, Optical Radiation Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
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Barnes RA, Roth CC, Beier HT, Noojin G, Valdez C, Bixler J, Moen E, Shadaram M, Ibey BL. Probe beam deflection optical imaging of thermal and mechanical phenomena resulting from nanosecond electric pulse (nsEP) exposure in-vitro. Opt Express 2017; 25:6621-6643. [PMID: 28381008 DOI: 10.1364/oe.25.006621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electric-field induced physical phenomena, such as thermal, mechanical and electrochemical dynamics, may be the driving mechanism behind bioeffects observed in mammalian cells during exposure to nanosecond-duration electric pulses (nsEP) in-vitro. Correlating a driving mechanism to a biological response requires the experimental measurement and quantification of all physical dynamics resulting from the nsEP stimulus. A passive and electromagnetic interference (EMI) immune sensor is required to resolve these dynamics in high strength electric fields. The probe beam deflection technique (PBDT) is a passive and EMI immune optical method for quantifying and imaging refractive index gradients in liquids and gases, both dynamic and static, with nanosecond temporal resolution. In this work, a probe beam deflection imaging system was designed to acquire 2-D time-lapse images of thermal/mechanical dynamics resulting from monopolar and bipolar nsEP stimulus.
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Tolstykh GP, Tarango M, Roth CC, Ibey BL. Nanosecond pulsed electric field induced dose dependent phosphatidylinositol-4,5-bisphosphate signaling and intracellular electro-sensitization. Biochimica et Biophysica Acta (BBA) - Biomembranes 2017; 1859:438-445. [DOI: 10.1016/j.bbamem.2017.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/15/2016] [Accepted: 01/02/2017] [Indexed: 12/11/2022]
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Roth CC, Glickman RD, Martens SL, Echchgadda I, Beier HT, Barnes RA, Ibey BL. Adult human dermal fibroblasts exposed to nanosecond electrical pulses exhibit genetic biomarkers of mechanical stress. Biochem Biophys Rep 2017; 9:302-309. [PMID: 28956017 PMCID: PMC5614618 DOI: 10.1016/j.bbrep.2017.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 11/17/2016] [Accepted: 01/24/2017] [Indexed: 11/29/2022] Open
Abstract
Background Exposure of cells to very short (<1 µs) electric pulses in the megavolt/meter range have been shown to cause a multitude of effects, both physical and molecular in nature. Physically, nanosecond electrical pulses (nsEP) can cause disruption of the plasma membrane, cellular swelling, shrinking and blebbing. Molecularly, nsEP have been shown to activate signaling pathways, produce oxidative stress, stimulate hormone secretion and induce both apoptotic and necrotic death. We hypothesize that studying the genetic response of primary human dermal fibroblasts exposed to nsEP, will gain insight into the molecular mechanism(s) either activated directly by nsEP, or indirectly through electrophysiology interactions. Methods Microarray analysis in conjunction with quantitative real time polymerase chain reaction (qRT-PCR) was used to screen and validate genes selectively upregulated in response to nsEP exposure. Results Expression profiles of 486 genes were found to be significantly changed by nsEP exposure. 50% of the top 20 responding genes coded for proteins located in two distinct cellular locations, the plasma membrane and the nucleus. Further analysis of five of the top 20 upregulated genes indicated that the HDFa cells’ response to nsEP exposure included many elements of a mechanical stress response. Conclusions We found that several genes, some of which are mechanosensitive, were selectively upregulated due to nsEP exposure. This genetic response appears to be a primary response to the stimuli and not a secondary response to cellular swelling. General significance This work provides strong evidence that cells exposed to nsEP interpret the insult as a mechanical stress. Global gene expression analysis was performed on primary cells exposed to nsEP. The bioeffects of nsEP on adult human dermal fibroblasts were investigated. Microarray analysis suggests nsEP imparts a mechanical stress on cells. FOS, NR4A2, ITPKB, KLHL24, and SOD2 were upregulated in response to nsEP.
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Affiliation(s)
- Caleb C Roth
- University of Texas Health Science Center San Antonio, School of Medicine, Dept. of Radiological Sciences, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.,General Dynamics IT, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.,Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Randolph D Glickman
- University of Texas Health Science Center San Antonio, School of Medicine, Dept. of Ophthalmology, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Stacey L Martens
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Ibtissam Echchgadda
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Hope T Beier
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Optical Radiation Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Ronald A Barnes
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Bennett L Ibey
- Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Bioeffects Division, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
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Tolstykh GP, Thompson GL, Beier HT, Steelman ZA, Ibey BL. nsPEF-induced PIP 2 depletion, PLC activity and actin cytoskeletal cortex remodeling are responsible for post-exposure cellular swelling and blebbing. Biochem Biophys Rep 2016; 9:36-41. [PMID: 28955986 PMCID: PMC5614542 DOI: 10.1016/j.bbrep.2016.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/11/2016] [Accepted: 11/08/2016] [Indexed: 01/11/2023] Open
Abstract
Cell swelling and blebbing has been commonly observed following nanosecond pulsed electric field (nsPEF) exposure. The hypothesized origin of these effects is nanoporation of the plasma membrane (PM) followed by transmembrane diffusion of extracellular fluid and disassembly of cortical actin structures. This investigation will provide evidence that shows passive movement of fluid into the cell through nanopores and increase of intracellular osmotic pressure are not solely responsible for this observed phenomena. We demonstrate that phosphatidylinositol-4,5-bisphosphate (PIP2) depletion and hydrolysis are critical steps in the chain reaction leading to cellular blebbing and swelling. PIP2 is heavily involved in osmoregulation by modulation of ion channels and also serves as an intracellular membrane anchor to cortical actin and phospholipase C (PLC). Given the rather critical role that PIP2 depletion appears to play in the response of cells to nsPEF exposure, it remains unclear how its downstream effects and, specifically, ion channel regulation may contribute to cellular swelling, blebbing, and unknown mechanisms of the lasting “permeabilization” of the PM. Nanosecond electric pulses (nsEPs) of high amplitude induce hydrolysis of PIP2. PLC activation is leading to post-exposure cellular swelling and blebbing. Ion channels modulation and nanoporation are responsible for cellular swelling. Cortical actin dissociation after PIP2 depletion is critical for cellular blebbing.
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Affiliation(s)
- Gleb P. Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, TX, USA
- Corespondence to: General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.
| | - Gary L. Thompson
- Oak Ridge Institute for Science & Education, JBSA Fort Sam Houston, TX, USA
| | - Hope T. Beier
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Optical Radiation Bioeffects Branch, JBSA Fort Sam Houston, TX, USA
| | | | - Bennett L. Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, TX, USA
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Cantu JC, Tarango M, Beier HT, Ibey BL. The biological response of cells to nanosecond pulsed electric fields is dependent on plasma membrane cholesterol. Biochimica et Biophysica Acta (BBA) - Biomembranes 2016; 1858:2636-2646. [DOI: 10.1016/j.bbamem.2016.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 06/09/2016] [Accepted: 07/14/2016] [Indexed: 01/06/2023]
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Walsh AJ, Tolstykh GP, Martens S, Ibey BL, Beier HT. Action potential block in neurons by infrared light. Neurophotonics 2016; 3:040501. [PMID: 27990450 PMCID: PMC5140263 DOI: 10.1117/1.nph.3.4.040501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/08/2016] [Indexed: 05/18/2023]
Abstract
Short infrared laser pulses (SILP) have many physiological effects on cells, including the ability to stimulate action potentials (APs) in neurons. Here, we show that SILPs can also reversibly block APs. Reversible AP block in hippocampal neurons was observed following SILP (0.26 to [Formula: see text]; 1.37 to 5.01 ms; 1869 nm) with the block persisting for more than 1 s with exposures greater than [Formula: see text]. AP block was sustained for 30 s with SILPs pulsed at 1 to 7 Hz. Full recovery of neuronal activity was observed 5 to 30 s post SILP exposure. These results indicate that SILP can be used for noncontact, reversible AP block. Due to the high spatial precision and noncontact manner of infrared light delivery, AP block by SILP (infrared neural inhibition) has the potential to transform medical care for sustained pain inhibition and suppression of unwanted nerve activity.
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Affiliation(s)
- Alex J. Walsh
- National Research Council, JBSA Fort Sam Houston, Texas 78234, United States
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, Texas 78234, United States
| | - Gleb P. Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, Texas 78234, United States
| | - Stacey Martens
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, Texas 78234, United States
| | - Bennett L. Ibey
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, Texas 78234, United States
| | - Hope T. Beier
- Air Force Research Laboratory, Bioeffects Division, JBSA Fort Sam Houston, Texas 78234, United States
- Address all correspondence to: Hope T. Beier, E-mail:
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Maswadi SM, Ibey BL, Roth CC, Tsyboulski DA, Beier HT, Glickman RD, Oraevsky AA. All-optical optoacoustic microscopy based on probe beam deflection technique. Photoacoustics 2016; 4:91-101. [PMID: 27761408 PMCID: PMC5063357 DOI: 10.1016/j.pacs.2016.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/02/2016] [Accepted: 02/20/2016] [Indexed: 05/11/2023]
Abstract
Optoacoustic (OA) microscopy using an all-optical system based on the probe beam deflection technique (PBDT) for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i) efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii) undistorted coupling of acoustic waves to the detector without the need for separation of the optical and acoustic paths, (iii) high sensitivity and (iv) ultrawide bandwidth. Because of the unimpeded optical path in PBDT, diffraction-limited lateral resolution can be readily achieved. The sensitivity of the current PBDT sensor of 22 μV/Pa and its noise equivalent pressure (NEP) of 11.4 Pa are comparable with these parameters of the optical micro-ring resonator and commercial piezoelectric ultrasonic transducers. Benefits of the present prototype OA microscope were demonstrated by successfully resolving micron-size details in histological sections of cardiac muscle.
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Affiliation(s)
- Saher M. Maswadi
- Oak Ridge Institute for Science and Education, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
- EchoLase, Inc., 5234 Tomas Circle, San Antonio, TX 78240, USA
| | - Bennett L. Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Caleb C. Roth
- School of Medicine, Dept. of Radiological Sciences, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | | | - Hope T. Beier
- Optical Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Randolph D. Glickman
- School of Medicine, Dept. of Ophthalmology, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
- EchoLase, Inc., 5234 Tomas Circle, San Antonio, TX 78240, USA
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Steelman ZA, Tolstykh GP, Beier HT, Ibey BL. Cellular response to high pulse repetition rate nanosecond pulses varies with fluorescent marker identity. Biochem Biophys Res Commun 2016; 478:1261-7. [DOI: 10.1016/j.bbrc.2016.08.107] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
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Moen EK, Ibey BL, Beier HT, Armani AM. Quantifying pulsed electric field-induced membrane nanoporation in single cells. Biochim Biophys Acta 2016; 1858:2795-2803. [PMID: 27535877 DOI: 10.1016/j.bbamem.2016.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/21/2022]
Abstract
Plasma membrane disruption can trigger a host of cellular activities. One commonly observed type of disruption is pore formation. Molecular dynamic (MD) simulations of simplified lipid membrane structures predict that controllably disrupting the membrane via nano-scale poration may be possible with nanosecond pulsed electric fields (nsPEF). Until recently, researchers hoping to verify this hypothesis experimentally have been limited to measuring the relatively slow process of fluorescent markers diffusing across the membrane, which is indirect evidence of nanoporation that could be channel-mediated. Leveraging recent advances in nonlinear optical microscopy, we elucidate the role of pulse parameters in nsPEF-induced membrane permeabilization in live cells. Unlike previous techniques, it is able to directly observe loss of membrane order at the onset of the pulse. We also develop a complementary theoretical model that relates increasing membrane permeabilization to membrane pore density. Due to the significantly improved spatial and temporal resolution possible with our imaging method, we are able to directly compare our experimental and theoretical results. Their agreement provides substantial evidence that nanoporation does occur and that its development is dictated by the electric field distribution.
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Affiliation(s)
- Erick K Moen
- Ming Hsieh Department of Electrical Engineering - Electrophysics, University of Southern California, 920 Bloom Walk, SSC, 502 Los Angeles, CA, USA.
| | - Bennett L Ibey
- Bioeffects Division, 711 Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam, Houston, TX 78234, USA
| | - Hope T Beier
- Bioeffects Division, 711 Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam, Houston, TX 78234, USA
| | - Andrea M Armani
- Ming Hsieh Department of Electrical Engineering - Electrophysics, University of Southern California, 920 Bloom Walk, SSC, 502 Los Angeles, CA, USA
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Ibey BL, Roth CC, Ledwig PB, Payne JA, Amato AL, Dalzell DR, Bernhard JA, Doroski MW, Mylacraine KS, Seaman RL, Nelson GS, Woods CW. Cellular effects of acute exposure to high peak power microwave systems: Morphology and toxicology. Bioelectromagnetics 2016; 37:141-151. [PMID: 26991689 DOI: 10.1002/bem.21962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 02/11/2016] [Indexed: 11/10/2022]
Abstract
Electric fields produced by advanced pulsed microwave transmitter technology now readily exceed the Institute of Electrical and Electronic Engineers (IEEE) C.95.1 peak E-field limit of 100 kV/m, highlighting a need for scientific validation of such a specific limit. Toward this goal, we exposed Jurkat Clone E-6 human lymphocyte preparations to 20 high peak power microwave (HPPM) pulses (120 ns duration) with a mean peak amplitude of 2.3 MV/m and standard deviation of 0.1 with the electric field at cells predicted to range from 0.46 to 2.7 MV/m, well in excess of current standard limit. We observed that membrane integrity and cell morphology remained unchanged 4 h after exposure and cell survival 24 h after exposure was not statistically different from sham exposure or control samples. Using flow cytometry to analyze membrane disruption and morphological changes per exposed cell, no changes were observed in HPPM-exposed samples. Current IEEE C95.1-2005 standards for pulsed radiofrequency exposure limits peak electric field to 100 kV/m for pulses shorter than 100 ms [IEEE (1995) PC95.1-Standard for Safety Levels with Respect to Human Exposure to Electric, Magnetic and Electromagnetic Fields, 0 Hz to 300 GHz, Institute of Electrical and Electronic Engineers: Piscataway, NJ, USA]. This may impose large exclusion zones that limit HPPM technology use. In this study, we offer evidence that maximum permissible exposure of 100 kV/m for peak electric field may be unnecessarily restrictive for HPPM devices. Bioelectromagnetics. 37:141-151, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Caleb C Roth
- General Dynamics Information Technology, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Patrick B Ledwig
- General Dynamics Information Technology, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Jason A Payne
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Alayna L Amato
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Danielle R Dalzell
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Joshua A Bernhard
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Michael W Doroski
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Kevin S Mylacraine
- General Dynamics Information Technology, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Ronald L Seaman
- General Dynamics Information Technology, Joint Base San Antonio, Fort Sam Houston, Texas
| | - Gregory S Nelson
- Directed Energy Division, High Power Microwave Applications Branch, Kirtland Air Force Base, New Mexico
| | - Clifford W Woods
- Directed Energy Division, High Power Microwave Applications Branch, Kirtland Air Force Base, New Mexico
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Moen EK, Ibey BL, Beier HT, Armani AM. Bipolar Nanosecond Pulses Mitigate Membrane Nanoporation. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Thompson GL, Roth CC, Kuipers MA, Tolstykh GP, Beier HT, Ibey BL. Permeabilization of the nuclear envelope following nanosecond pulsed electric field exposure. Biochem Biophys Res Commun 2015; 470:35-40. [PMID: 26721436 DOI: 10.1016/j.bbrc.2015.12.092] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 12/20/2015] [Indexed: 01/14/2023]
Abstract
Permeabilization of cell membranes occurs upon exposure to a threshold absorbed dose (AD) of nanosecond pulsed electric fields (nsPEF). The ultimate, physiological bioeffect of this exposure depends on the type of cultured cell and environment, indicating that cell-specific pathways and structures are stimulated. Here we investigate 10 and 600 ns duration PEF effects on Chinese hamster ovary (CHO) cell nuclei, where our hypothesis is that pulse disruption of the nuclear envelope membrane leads to observed cell death and decreased viability 24 h post-exposure. To observe short-term responses to nsPEF exposure, CHO cells have been stably transfected with two fluorescently-labeled proteins known to be sequestered for cellular chromosomal function within the nucleus - histone-2b (H2B) and proliferating cell nuclear antigen (PCNA). H2B remains associated with chromatin after nsPEF exposure, whereas PCNA leaks out of nuclei permeabilized by a threshold AD of 10 and 600 ns PEF. A downturn in 24 h viability, measured by MTT assay, is observed at the number of pulses required to induce permeabilization of the nucleus.
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Affiliation(s)
- Gary L Thompson
- Oak Ridge Institute for Science & Education, Joint Base San Antonio Fort Sam Houston, TX, 78234, USA.
| | - Caleb C Roth
- Department of Radiological Sciences, University of Texas Health Science Center at San Antonio, TX, 78234, USA
| | - Marjorie A Kuipers
- Radio Frequency Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234, USA
| | - Gleb P Tolstykh
- General Dynamics IT, Joint Base San Antonio Fort Sam Houston, TX, 78234, USA
| | - Hope T Beier
- Optical Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234, USA
| | - Bennett L Ibey
- Radio Frequency Radiation Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Joint Base San Antonio Fort Sam Houston, TX, 78234, USA
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Roth CC, Barnes RA, Ibey BL, Beier HT, Christopher Mimun L, Maswadi SM, Shadaram M, Glickman RD. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure. Sci Rep 2015; 5:15063. [PMID: 26450165 PMCID: PMC4598730 DOI: 10.1038/srep15063] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 09/14/2015] [Indexed: 11/11/2022] Open
Abstract
The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, electrochemical interactions, thermoelastic expansion, and others. To date, very limited research has investigated non-electric phenomena occurring during nsEP exposures and their potential effect on cell nanoporation. Of primary interest is the production of acoustic shock waves during nsEP exposure, as it is known that acoustic shock waves can cause membrane poration (sonoporation). Based on these observations, our group characterized the acoustic pressure transients generated by nsEP and determined if such transients played any role in nanoporation. In this paper, we show that nsEP exposures, equivalent to those used in cellular studies, are capable of generating high-frequency (2.5 MHz), high-intensity (>13 kPa) pressure transients. Using confocal microscopy to measure cell uptake of YO-PRO®-1 (indicator of nanoporation of the plasma membrane) and changing the electrode geometry, we determined that acoustic waves alone are not responsible for poration of the membrane.
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Affiliation(s)
- Caleb C Roth
- School of Medicine, Dept. of Radiological Sciences, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, USA 78229
| | - Ronald A Barnes
- Dept. of Electrical Engineering, University of Texas San Antonio, 1 UTSA Circle, San Antonio, Texas, USA 78249
| | - Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Road, JBSA Fort Sam Houston, Texas, USA 78234
| | - Hope T Beier
- Optical Radiation Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Road, JBSA Fort Sam Houston, Texas, USA 78234
| | - L Christopher Mimun
- Dept. of Physics, University of Texas San Antonio, 1 UTSA Circle, San Antonio, Texas, USA 78249
| | - Saher M Maswadi
- Dept. of Electrical Engineering, University of Texas San Antonio, 1 UTSA Circle, San Antonio, Texas, USA 78249
| | - Mehdi Shadaram
- Dept. of Electrical Engineering, University of Texas San Antonio, 1 UTSA Circle, San Antonio, Texas, USA 78249
| | - Randolph D Glickman
- School of Medicine, Dept. of Ophthalmology, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, USA 78229
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Ullery JC, Tarango M, Roth CC, Ibey BL. Activation of autophagy in response to nanosecond pulsed electric field exposure. Biochem Biophys Res Commun 2015; 458:411-7. [PMID: 25660455 DOI: 10.1016/j.bbrc.2015.01.131] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/26/2015] [Indexed: 11/24/2022]
Abstract
Previous work demonstrated significant changes in cellular membranes following exposure of cells to nanosecond pulsed electric fields (nsPEF), including nanoporation and increases in intracellular calcium concentration. While it is known that nsPEF exposure can cause cell death, how cells repair and survive nsPEF-induced cellular damage is not well understood. In this paper, we investigated whether autophagy is stimulated following nsPEF exposure to repair damaged membranes, proteins, and/or organelles in a pro-survival response. We hypothesized that autophagy is activated to repair nsPEF-induced plasma membrane damage and overwhelming this compensatory mechanism results in cell death. Activation of autophagy and subsequent cell death pathways were assessed measuring toxicity, gene and protein expression of autophagy markers, and by monitoring autophagosome formation and maturation using fluorescent microscopy. Results show that autophagy is activated at subtoxic nsPEF doses, as a compensatory mechanism to repair membrane damage. However, prolonged exposure results in increased cell death and a concomitant decrease in autophagic markers. These results suggest that cells take an active role in membrane repair, through autophagy, following exposure to nsPEF.
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Affiliation(s)
- Jody C Ullery
- General Dynamics Information Technology, JBSA Fort Sam Houston, TX, USA.
| | - Melissa Tarango
- General Dynamics Information Technology, JBSA Fort Sam Houston, TX, USA
| | - Caleb C Roth
- School of Medicine, Department of Radiological Sciences, University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Human Effectiveness Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, TX, USA
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Moen EK, Ibey BL, Beier HT. Detecting subtle plasma membrane perturbation in living cells using second harmonic generation imaging. Biophys J 2014; 106:L37-40. [PMID: 24853757 DOI: 10.1016/j.bpj.2014.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/20/2014] [Accepted: 04/07/2014] [Indexed: 01/20/2023] Open
Abstract
The requirement of center asymmetry for the creation of second harmonic generation (SHG) signals makes it an attractive technique for visualizing changes in interfacial layers such as the plasma membrane of biological cells. In this article, we explore the use of lipophilic SHG probes to detect minute perturbations in the plasma membrane. Three candidate probes, Di-4-ANEPPDHQ (Di-4), FM4-64, and all-trans-retinol, were evaluated for SHG effectiveness in Jurkat cells. Di-4 proved superior with both strong SHG signal and limited bleaching artifacts. To test whether rapid changes in membrane symmetry could be detected using SHG, we exposed cells to nanosecond-pulsed electric fields, which are believed to cause formation of nanopores in the plasma membrane. Upon nanosecond-pulsed electric fields exposure, we observed an instantaneous drop of ~50% in SHG signal from the anodic pole of the cell. When compared to the simultaneously acquired fluorescence signals, it appears that the signal change was not due to the probe diffusing out of the membrane or changes in membrane potential or fluidity. We hypothesize that this loss in SHG signal is due to disruption in the interfacial nature of the membrane. The results show that SHG imaging has great potential as a tool for measuring rapid and subtle plasma membrane disturbance in living cells.
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Affiliation(s)
- Erick K Moen
- Department of Electrical Engineering - Electrophysics, University of Southern California at Los Angeles, Los Angeles, California
| | - Bennett L Ibey
- Bioeffects Division, Air Force Research Laboratory, Fort Sam Houston, Texas
| | - Hope T Beier
- Bioeffects Division, Air Force Research Laboratory, Fort Sam Houston, Texas.
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Tolstykh GP, Beier HT, Roth CC, Thompson GL, Ibey BL. 600ns pulse electric field-induced phosphatidylinositol4,5-bisphosphate depletion. Bioelectrochemistry 2014; 100:80-7. [DOI: 10.1016/j.bioelechem.2014.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 01/11/2014] [Accepted: 01/21/2014] [Indexed: 01/15/2023]
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Beier HT, Tolstykh GP, Musick JD, Thomas RJ, Ibey BL. Plasma membrane nanoporation as a possible mechanism behind infrared excitation of cells. J Neural Eng 2014; 11:066006. [DOI: 10.1088/1741-2560/11/6/066006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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40
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Estlack LE, Roth CC, Thompson GL, Lambert WA, Ibey BL. Nanosecond pulsed electric fields modulate the expression of Fas/CD95 death receptor pathway regulators in U937 and Jurkat Cells. Apoptosis 2014; 19:1755-68. [DOI: 10.1007/s10495-014-1041-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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41
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Thompson GL, Roth CC, Dalzell DR, Kuipers M, Ibey BL. Calcium influx affects intracellular transport and membrane repair following nanosecond pulsed electric field exposure. J Biomed Opt 2014; 19:055005. [PMID: 24825506 DOI: 10.1117/1.jbo.19.5.055005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
The cellular response to subtle membrane damage following exposure to nanosecond pulsed electric fields (nsPEF) is not well understood. Recent work has shown that when cells are exposed to nsPEF, ion permeable nanopores (<2 nm) are created in the plasma membrane in contrast to larger diameter pores (>2 nm) created by longer micro- and millisecond duration pulses. Nanoporation of the plasma membrane by nsPEF has been shown to cause a transient increase in intracellular calcium concentration within milliseconds after exposure. Our research objective is to determine the impact of nsPEF on calcium-dependent structural and repair systems in mammalian cells. Chinese hamster ovary (CHO-K1) cells were exposed in the presence and absence of calcium ions in the outside buffer to either 1 or 20, 600-ns duration electrical pulses at 16.2 kV/cm, and pore size was determined using propidium iodide and calcium green. Membrane organization was observed with morphological changes and increases in FM1-43 fluorescence. Migration of lysosomes, implicated in membrane repair, was followed using confocal microscopy of red fluorescent protein-tagged LAMP1. Microtubule structure was imaged using mEmerald-tubulin. We found that at high 600-ns PEF dosage, calcium-induced membrane restructuring and microtubule depolymerization coincide with interruption of membrane repair via lysosomal exocytosis.
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Affiliation(s)
- Gary Lee Thompson
- Oak Ridge Institute for Science and Education, JBSA Fort Sam Houston, Texas 78234
| | - Caleb C Roth
- University of Texas Health Science Center at San Antonio, Department of Radiological Sciences, San Antonio, Texas 78229
| | | | - Marjorie Kuipers
- 711th Human Performance Wing, JBSA Fort Sam Houston, Texas 78234
| | - Bennett L Ibey
- 711th Human Performance Wing, JBSA Fort Sam Houston, Texas 78234
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Pakhomov AG, Semenov I, Xiao S, Pakhomova ON, Gregory B, Schoenbach KH, Ullery JC, Beier HT, Rajulapati SR, Ibey BL. Cancellation of cellular responses to nanoelectroporation by reversing the stimulus polarity. Cell Mol Life Sci 2014; 71:4431-41. [PMID: 24748074 DOI: 10.1007/s00018-014-1626-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/03/2014] [Accepted: 04/04/2014] [Indexed: 12/26/2022]
Abstract
Nanoelectroporation of biomembranes is an effect of high-voltage, nanosecond-duration electric pulses (nsEP). It occurs both in the plasma membrane and inside the cell, and nanoporated membranes are distinguished by ion-selective and potential-sensitive permeability. Here we report a novel phenomenon of bioeffects cancellation that puts nsEP cardinally apart from the conventional electroporation and electrostimulation by milli- and microsecond pulses. We compared the effects of 60- and 300-ns monopolar, nearly rectangular nsEP on intracellular Ca(2+) mobilization and cell survival with those of bipolar 60 + 60 and 300 + 300 ns pulses. For diverse endpoints, exposure conditions, pulse numbers (1-60), and amplitudes (15-60 kV/cm), the addition of the second phase cancelled the effects of the first phase. The overall effect of bipolar pulses was profoundly reduced, despite delivering twofold more energy. Cancellation also took place when two phases were separated into two independent nsEP of opposite polarities; it gradually tapered out as the interval between two nsEP increased, but was still present even at a 10-µs interval. The phenomenon of cancellation is unique for nsEP and has not been predicted by the equivalent circuit, transport lattice, and molecular dynamics models of electroporation. The existing paradigms of membrane permeabilization by nsEP will need to be modified. Here we discuss the possible involvement of the assisted membrane discharge, two-step oxidation of membrane phospholipids, and reverse transmembrane ion transport mechanisms. Cancellation impacts nsEP applications in cancer therapy, electrostimulation, and biotechnology, and provides new insights into effects of more complex waveforms, including pulsed electromagnetic emissions.
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Affiliation(s)
- Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA,
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Thompson GL, Roth C, Tolstykh G, Kuipers M, Ibey BL. Disruption of the actin cortex contributes to susceptibility of mammalian cells to nanosecond pulsed electric fields. Bioelectromagnetics 2014; 35:262-72. [DOI: 10.1002/bem.21845] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 01/20/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Gary L. Thompson
- National Research Council; Joint Base San Antonio Fort Sam Houston; San Antonio Texas
| | - Caleb Roth
- Department of Radiological Sciences; University of Texas Health Science Center at San Antonio; San Antonio Texas
| | - Gleb Tolstykh
- National Research Council; Joint Base San Antonio Fort Sam Houston; San Antonio Texas
| | - Marjorie Kuipers
- Radio Frequency Bioeffects Branch; Bioeffects Division; Human Effectiveness Directorate; Air Force Research Laboratory; Joint Base San Antonio Fort Sam Houston; San Antonio Texas
| | - Bennett L. Ibey
- Radio Frequency Bioeffects Branch; Bioeffects Division; Human Effectiveness Directorate; Air Force Research Laboratory; Joint Base San Antonio Fort Sam Houston; San Antonio Texas
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Pakhomov AG, Xiao S, Pakhomova ON, Semenov I, Kuipers MA, Ibey BL. Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling. Bioelectrochemistry 2014; 100:88-95. [PMID: 24507565 DOI: 10.1016/j.bioelechem.2014.01.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 12/27/2013] [Accepted: 01/14/2014] [Indexed: 01/06/2023]
Abstract
Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance.
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Affiliation(s)
- Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA; Dept. of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Marjorie A Kuipers
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Fort Sam Houston, TX, USA
| | - Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Fort Sam Houston, TX, USA
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Beier HT, Ibey BL. Experimental comparison of the high-speed imaging performance of an EM-CCD and sCMOS camera in a dynamic live-cell imaging test case. PLoS One 2014; 9:e84614. [PMID: 24404178 PMCID: PMC3880299 DOI: 10.1371/journal.pone.0084614] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 11/15/2013] [Indexed: 12/19/2022] Open
Abstract
The study of living cells may require advanced imaging techniques to track weak and rapidly changing signals. Fundamental to this need is the recent advancement in camera technology. Two camera types, specifically sCMOS and EM-CCD, promise both high signal-to-noise and high speed (>100 fps), leaving researchers with a critical decision when determining the best technology for their application. In this article, we compare two cameras using a live-cell imaging test case in which small changes in cellular fluorescence must be rapidly detected with high spatial resolution. The EM-CCD maintained an advantage of being able to acquire discernible images with a lower number of photons due to its EM-enhancement. However, if high-resolution images at speeds approaching or exceeding 1000 fps are desired, the flexibility of the full-frame imaging capabilities of sCMOS is superior.
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Affiliation(s)
- Hope T. Beier
- 1th Human Performance Wing, Bioeffects Division, Air Force Research Laboratory, Fort Sam Houston, Texas, United States of America
- * E-mail:
| | - Bennett L. Ibey
- 1th Human Performance Wing, Bioeffects Division, Air Force Research Laboratory, Fort Sam Houston, Texas, United States of America
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46
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Ibey BL, Ullery JC, Pakhomova ON, Roth CC, Semenov I, Beier HT, Tarango M, Xiao S, Schoenbach KH, Pakhomov AG. Bipolar nanosecond electric pulses are less efficient at electropermeabilization and killing cells than monopolar pulses. Biochem Biophys Res Commun 2013; 443:568-73. [PMID: 24332942 DOI: 10.1016/j.bbrc.2013.12.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 12/02/2013] [Indexed: 12/18/2022]
Abstract
Multiple studies have shown that bipolar (BP) electric pulses in the microsecond range are more effective at permeabilizing cells while maintaining similar cell survival rates as compared to monopolar (MP) pulse equivalents. In this paper, we investigated whether the same advantage existed for BP nanosecond-pulsed electric fields (nsPEF) as compared to MP nsPEF. To study permeabilization effectiveness, MP or BP pulses were delivered to single Chinese hamster ovary (CHO) cells and the response of three dyes, Calcium Green-1, propidium iodide (PI), and FM1-43, was measured by confocal microscopy. Results show that BP pulses were less effective at increasing intracellular calcium concentration or PI uptake and cause less membrane reorganization (FM1-43) than MP pulses. Twenty-four hour survival was measured in three cell lines (Jurkat, U937, CHO) and over ten times more BP pulses were required to induce death as compared to MP pulses of similar magnitude and duration. Flow cytometry analysis of CHO cells after exposure (at 15 min) revealed that to achieve positive FITC-Annexin V and PI expression, ten times more BP pulses were required than MP pulses. Overall, unlike longer pulse exposures, BP nsPEF exposures proved far less effective at both membrane permeabilization and cell killing than MP nsPEF.
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Affiliation(s)
- Bennett L Ibey
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA.
| | - Jody C Ullery
- General Dynamics Information Systems, JBSA Fort Sam Houston, TX, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Caleb C Roth
- General Dynamics Information Systems, JBSA Fort Sam Houston, TX, USA; Department of Radiological Sciences, University of Texas Health Science Center San Antonio, San Antonio, TX 78229 USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Hope T Beier
- Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | - Melissa Tarango
- General Dynamics Information Systems, JBSA Fort Sam Houston, TX, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Karl H Schoenbach
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
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Tolstykh GP, Beier HT, Roth CC, Thompson GL, Payne JA, Kuipers MA, Ibey BL. Activation of intracellular phosphoinositide signaling after a single 600 nanosecond electric pulse. Bioelectrochemistry 2013; 94:23-9. [DOI: 10.1016/j.bioelechem.2013.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/10/2013] [Accepted: 05/13/2013] [Indexed: 02/03/2023]
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48
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Echchgadda I, Grundt JA, Tarango M, Ibey BL, Tongue T, Liang M, Xin H, Wilmink GJ. Using a portable terahertz spectrometer to measure the optical properties of in vivo human skin. J Biomed Opt 2013; 18:120503. [PMID: 24343433 DOI: 10.1117/1.jbo.18.12.120503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/11/2013] [Indexed: 05/04/2023]
Abstract
Terahertz (THz) time-domain spectroscopy systems permit the measurement of a tissue's hydration level. This feature makes THz spectrometers excellent tools for the noninvasive assessment of skin; however, current systems are large, heavy and not ideal for clinical settings. We previously demonstrated that a portable, compact THz spectrometer permitted measurement of porcine skin optical properties that were comparable to those collected with conventional systems. In order to move toward human use of this system, the goal for this study was to measure the absorption coefficient (μa) and index of refraction (n) of human subjects in vivo. Spectra were collected from 0.1 to 2 THz, and measurements were made from skin at three sites: the palm, ventral and dorsal forearm. Additionally, we used a multiprobe adapter system to measure each subject's skin hydration levels, transepidermal water loss, and melanin concentration. Our results suggest that the measured optical properties varied considerably for skin tissues that exhibited dissimilar hydration levels. These data provide a framework for using compact THz spectrometers for clinical applications.
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Affiliation(s)
- Ibtissam Echchgadda
- National Academy of Sciences, NRC Research Associateship, Washington DC 20001bGeneral Dynamics Information Technology, Fort Sam Houston, Texas 78234
| | - Jessica A Grundt
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Fort Sam Houston, Texas 78234
| | - Melissa Tarango
- General Dynamics Information Technology, Fort Sam Houston, Texas 78234
| | - Bennett L Ibey
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Fort Sam Houston, Texas 78234
| | - Thomas Tongue
- Zomega Terahertz Corporation, East Greenbush, New York 12061
| | - Min Liang
- University of Arizona, Electrical and Computer Engineering, Tucson, Arizona 85721
| | - Hao Xin
- University of Arizona, Electrical and Computer Engineering, Tucson, Arizona 85721
| | - Gerald J Wilmink
- Air Force Research Laboratory, Radio Frequency Bioeffects Branch, Fort Sam Houston, Texas 78234
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Roth CC, Tolstykh GP, Payne JA, Kuipers MA, Thompson GL, DeSilva MN, Ibey BL. Nanosecond pulsed electric field thresholds for nanopore formation in neural cells. J Biomed Opt 2013; 18:035005. [PMID: 23532338 DOI: 10.1117/1.jbo.18.3.035005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The persistent influx of ions through nanopores created upon cellular exposure to nanosecond pulse electric fields (nsPEF) could be used to modulate neuronal function. One ion, calcium (Ca(2+)), is important to action potential firing and regulates many ion channels. However, uncontrolled hyper-excitability of neurons leads to Ca(2+) overload and neurodegeneration. Thus, to prevent unintended consequences of nsPEF-induced neural stimulation, knowledge of optimum exposure parameters is required. We determined the relationship between nsPEF exposure parameters (pulse width and amplitude) and nanopore formation in two cell types: rodent neuroblastoma (NG108) and mouse primary hippocampal neurons (PHN). We identified thresholds for nanoporation using Annexin V and FM1-43, to detect changes in membrane asymmetry, and through Ca(2+) influx using Calcium Green. The ED50 for a single 600 ns pulse, necessary to cause uptake of extracellular Ca(2+), was 1.76 kV/cm for NG108 and 0.84 kV/cm for PHN. At 16.2 kV/cm, the ED50 for pulse width was 95 ns for both cell lines. Cadmium, a nonspecific Ca(2+) channel blocker, failed to prevent Ca(2+) uptake suggesting that observed influx is likely due to nanoporation. These data demonstrate that moderate amplitude single nsPEF exposures result in rapid Ca(2+) influx that may be capable of controllably modulating neurological function.
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Affiliation(s)
- Caleb C Roth
- University of Texas Health Science Center, Department of Radiology, San Antonio, Texas 78229, USA.
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Beier HT, Roth CC, Tolstykh GP, Ibey BL. Resolving the spatial kinetics of electric pulse-induced ion release. Biochem Biophys Res Commun 2012; 423:863-6. [DOI: 10.1016/j.bbrc.2012.06.055] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 06/12/2012] [Indexed: 12/17/2022]
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