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Hu Y, Wei J, Shen Y, Chen S, Chen X. Barrier-breaking effects of ultrasonic cavitation for drug delivery and biomarker release. ULTRASONICS SONOCHEMISTRY 2023; 94:106346. [PMID: 36870921 PMCID: PMC10040969 DOI: 10.1016/j.ultsonch.2023.106346] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/15/2023] [Accepted: 02/23/2023] [Indexed: 05/27/2023]
Abstract
Recently, emerging evidence has demonstrated that cavitation actually creates important bidirectional channels on biological barriers for both intratumoral drug delivery and extratumoral biomarker release. To promote the barrier-breaking effects of cavitation for both therapy and diagnosis, we first reviewed recent technical advances of ultrasound and its contrast agents (microbubbles, nanodroplets, and gas-stabilizing nanoparticles) and then reported the newly-revealed cavitation physical details. In particular, we summarized five types of cellular responses of cavitation in breaking the plasma membrane (membrane retraction, sonoporation, endocytosis/exocytosis, blebbing and apoptosis) and compared the vascular cavitation effects of three different types of ultrasound contrast agents in breaking the blood-tumor barrier and tumor microenvironment. Moreover, we highlighted the current achievements of the barrier-breaking effects of cavitation in mediating drug delivery and biomarker release. We emphasized that the precise induction of a specific cavitation effect for barrier-breaking was still challenged by the complex combination of multiple acoustic and non-acoustic cavitation parameters. Therefore, we provided the cutting-edge in-situ cavitation imaging and feedback control methods and suggested the development of an international cavitation quantification standard for the clinical guidance of cavitation-mediated barrier-breaking effects.
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Affiliation(s)
- Yaxin Hu
- School of Biomedical Engineering, Medical School, Shenzhen University, Shenzhen, Guangdong, 518060, PR China; National-regional Key Technology Engineering Laboratory for Medical Ultrasound, Shenzhen University, Shenzhen, Guangdong, 518060, PR China
| | - Jianpeng Wei
- School of Biomedical Engineering, Medical School, Shenzhen University, Shenzhen, Guangdong, 518060, PR China; National-regional Key Technology Engineering Laboratory for Medical Ultrasound, Shenzhen University, Shenzhen, Guangdong, 518060, PR China
| | - Yuanyuan Shen
- School of Biomedical Engineering, Medical School, Shenzhen University, Shenzhen, Guangdong, 518060, PR China; National-regional Key Technology Engineering Laboratory for Medical Ultrasound, Shenzhen University, Shenzhen, Guangdong, 518060, PR China
| | - Siping Chen
- School of Biomedical Engineering, Medical School, Shenzhen University, Shenzhen, Guangdong, 518060, PR China; National-regional Key Technology Engineering Laboratory for Medical Ultrasound, Shenzhen University, Shenzhen, Guangdong, 518060, PR China
| | - Xin Chen
- School of Biomedical Engineering, Medical School, Shenzhen University, Shenzhen, Guangdong, 518060, PR China; National-regional Key Technology Engineering Laboratory for Medical Ultrasound, Shenzhen University, Shenzhen, Guangdong, 518060, PR China.
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Yu J, Chen Z, Yan F. Advances in mechanism studies on ultrasonic gene delivery at cellular level. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 142:1-9. [PMID: 30031881 DOI: 10.1016/j.pbiomolbio.2018.07.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 01/23/2023]
Abstract
Ultrasound provides a means for intracellular gene delivery, contributing to a noninvasive and spatiotemporally controllable strategy suitable for clinical applications. Many studies have been done to provide mechanisms of ultrasound-mediated gene delivery at the cellular level. This review summarizes the studies on the important aspects of the mechanisms, providing an overview of recent progress in cellular experiment of ultrasound-mediated gene delivery.
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Affiliation(s)
- Jinsui Yu
- Department of Ultrasound Medicine, Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, PR China
| | - Zhiyi Chen
- Department of Ultrasound Medicine, Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, PR China.
| | - Fei Yan
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, PR China.
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Hussein F, Antonescu C, Karshafian R. Ultrasound and microbubble induced release from intracellular compartments. BMC Biotechnol 2017; 17:45. [PMID: 28521780 PMCID: PMC5437622 DOI: 10.1186/s12896-017-0364-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/09/2017] [Indexed: 11/10/2022] Open
Abstract
Background Ultrasound and microbubbles (USMB) have been shown to enhance the intracellular uptake of molecules, generally thought to occur as a result of sonoporation. The underlying mechanism associated with USMB-enhanced intracellular uptake such as membrane disruption and endocytosis may also be associated with USMB-induced release of cellular materials to the extracellular milieu. This study investigates USMB effects on the molecular release from cells through membrane-disruption and exocytosis. Results USMB induced the release of 19% and 67% of GFP from the cytoplasm in viable and non-viable cells, respectively. Tfn release from early/recycling endosomes increased by 23% in viable cells upon USMB treatment. In addition, the MFI of LAMP-1 antibody increased by 50% in viable cells, suggesting USMB-stimulated lysosome exocytosis. In non-viable cells, labeling of LAMP-1 intracellular structures in the absence of cell permeabilization by detergents suggests that USMB-induced cell death correlates with lysosomal permeabilization. Conclusions In conclusion, USMB enhanced the molecular release from the cytoplasm, lysosomes, and early/recycling endosomes. Electronic supplementary material The online version of this article (doi:10.1186/s12896-017-0364-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Farah Hussein
- Department of Physics, Ryerson University, 350 Victoria Street Toronto, Ontario, M5B 2K3, Canada
| | - Costin Antonescu
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada.,Keenan Research Centre, St. Michael's Hospital, Toronto, Canada
| | - Raffi Karshafian
- Department of Physics, Ryerson University, 350 Victoria Street Toronto, Ontario, M5B 2K3, Canada. .,Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Canada. .,Keenan Research Centre, St. Michael's Hospital, Toronto, Canada.
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Kothapalli SVVN, Wiklund M, Janerot-Sjoberg B, Paradossi G, Grishenkov D. Investigation of polymer-shelled microbubble motions in acoustophoresis. ULTRASONICS 2016; 70:275-283. [PMID: 27261567 DOI: 10.1016/j.ultras.2016.05.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 03/30/2016] [Accepted: 05/19/2016] [Indexed: 06/05/2023]
Abstract
The objective of this paper is to explore the trajectory motion of microsize (typically smaller than a red blood cell) encapsulated polymer-shelled gas bubbles propelled by radiation force in an acoustic standing-wave field and to compare the corresponding movements of solid polymer microbeads. The experimental setup consists of a microfluidic chip coupled to a piezoelectric crystal (PZT) with a resonance frequency of about 2.8MHz. The microfluidic channel consists of a rectangular chamber with a width, w, corresponding to one wavelength of the ultrasound standing wave. It creates one full wave ultrasound of a standing-wave pattern with two pressure nodes at w/4 and 3w/4 and three antinodes at 0, w/2, and w. The peak-to-peak amplitude of the electrical potential over the PZT was varied between 1 and 10V. The study is limited to no-flow condition. From Gor'kov's potential equation, the acoustic contrast factor, Φ, for the polymer-shelled microbubbles was calculated to about -60.7. Experimental results demonstrate that the polymer-shelled microbubbles are translated and accumulated at the pressure antinode planes. This trajectory motion of polymer-shelled microbubbles toward the pressure antinode plane is similar to what has been described for other acoustic contrast particles with a negative Φ. First, primary radiation forces dragged the polymer-shelled microbubbles into proximity with each other at the pressure antinode planes. Then, primary and secondary radiation forces caused them to quickly aggregate at different spots along the channel. The relocation time for polymer-shelled microbubbles was 40 times shorter than that for polymer microbeads, and in contrast to polymer microbeads, the polymer-shelled microbubbles were actuated even at driving voltages (proportional to radiation forces) as low as 1V. In short, the polymer-shelled microbubbles demonstrate the behavior attributed to the negative acoustic contrast factor particles and thus can be trapped at the antinode plane and thereby separated from particles having a positive acoustic contrast factor, such as for example solid particles and cells. This phenomenon could be utilized in exploring future applications, such as bioassay, bioaffinity, and cell interaction studies in vitro in a well-controlled environment.
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Affiliation(s)
- Satya V V N Kothapalli
- Department of Medical Engineering, School of Technology and Health, KTH Royal Institute of Technology, SE-142 51 Stockholm, Sweden
| | - Martin Wiklund
- Department of Applied Physics, KTH-Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Birgitta Janerot-Sjoberg
- Department of Medical Engineering, School of Technology and Health, KTH Royal Institute of Technology, SE-142 51 Stockholm, Sweden; Department of Clinical Science, Intervention and Technology, Karolinska Institute, SE-142 51 Stockholm, Sweden; Department of Clinical Physiology, Karolinska University Hospital, SE-142 51 Stockholm, Sweden
| | - Gaio Paradossi
- Dipartimento di Chimica, Università di Roma Tor Vergata, 00133 Rome, Italy
| | - Dmitry Grishenkov
- Department of Medical Engineering, School of Technology and Health, KTH Royal Institute of Technology, SE-142 51 Stockholm, Sweden; Department of Clinical Science, Intervention and Technology, Karolinska Institute, SE-142 51 Stockholm, Sweden; Department of Clinical Physiology, Karolinska University Hospital, SE-142 51 Stockholm, Sweden.
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Johnston K, Tapia-Siles C, Gerold B, Postema M, Cochran S, Cuschieri A, Prentice P. Periodic shock-emission from acoustically driven cavitation clouds: a source of the subharmonic signal. ULTRASONICS 2014; 54:2151-8. [PMID: 25015000 DOI: 10.1016/j.ultras.2014.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/09/2014] [Accepted: 06/09/2014] [Indexed: 05/12/2023]
Abstract
Single clouds of cavitation bubbles, driven by 254kHz focused ultrasound at pressure amplitudes in the range of 0.48-1.22MPa, have been observed via high-speed shadowgraphic imaging at 1×10(6) frames per second. Clouds underwent repetitive growth, oscillation and collapse (GOC) cycles, with shock-waves emitted periodically at the instant of collapse during each cycle. The frequency of cloud collapse, and coincident shock-emission, was primarily dependent on the intensity of the focused ultrasound driving the activity. The lowest peak-to-peak pressure amplitude of 0.48MPa generated shock-waves with an average period of 7.9±0.5μs, corresponding to a frequency of f0/2, half-harmonic to the fundamental driving. Increasing the intensity gave rise to GOC cycles and shock-emission periods of 11.8±0.3, 15.8±0.3, 19.8±0.2μs, at pressure amplitudes of 0.64, 0.92 and 1.22MPa, corresponding to the higher-order subharmonics of f0/3, f0/4 and f0/5, respectively. Parallel passive acoustic detection, filtered for the fundamental driving, revealed features that correlated temporally to the shock-emissions observed via high-speed imaging, p(two-tailed) < 0.01 (r=0.996, taken over all data). Subtracting the isolated acoustic shock profiles from the raw signal collected from the detector, demonstrated the removal of subharmonic spectral peaks, in the frequency domain. The larger cavitation clouds (>200μm diameter, at maximum inflation), that developed under insonations of peak-to-peak pressure amplitudes >1.0MPa, emitted shock-waves with two or more fronts suggesting non-uniform collapse of the cloud. The observations indicate that periodic shock-emissions from acoustically driven cavitation clouds provide a source for the cavitation subharmonic signal, and that shock structure may be used to study intra-cloud dynamics at sub-microsecond timescales.
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Affiliation(s)
- Keith Johnston
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK
| | - Cecilia Tapia-Siles
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK
| | - Bjoern Gerold
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK; Diagnostic Sonar Ltd., Livingston EH54 7BX, UK
| | - Michiel Postema
- Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen, Norway
| | - Sandy Cochran
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK
| | - Alfred Cuschieri
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK
| | - Paul Prentice
- Institute for Medical Science and Technology, Division of Imaging and Technology, University of Dundee, Dundee DD2 1FD, UK; Diagnostic Sonar Ltd., Livingston EH54 7BX, UK.
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Wang Y, Bai WK, Shen E, Hu B. Sonoporation by low-frequency and low-power ultrasound enhances chemotherapeutic efficacy in prostate cancer cells in vitro.. Oncol Lett 2013; 6:495-498. [PMID: 24137354 PMCID: PMC3789114 DOI: 10.3892/ol.2013.1389] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 04/17/2013] [Indexed: 01/24/2023] Open
Abstract
Combination therapy is used to optimize anticancer efficacy and reduce the toxicity and side-effects of drugs upon systemic administration. Ultrasound (US) combined with micro-bubbles (UM) enhances the intracellular uptake of cytotoxic drugs by tumor cells, particularly drug-resistant cells. In the present study, low-frequency and low-energy US (US irradiation conditions: frequency, 21 kHz; power density, 0.113 W/cm2; exposure time, 2 min at a duty cycle of 70%; and valid treatment time, 84 sec) were used in combination with microbubbles (100 μl/ml) to deliver mitoxantrone HCl (MIT) to DU145 cells. The results showed that UM did not change the cell viability in the short- or long-term. However, UM statistically enhanced the therapeutic effects and up to 31.26±3.34% of the cells exposed to UM were permeabilized compared with 9.74±2.55% of cells in the control, when using calcein (MW, 622.53) as a fluorogenic marker. Notably, UM affected the migration capability of the DU145 cells at 6 h post-treatment. In conclusion, the ultrasonic parameters used in the present study enhanced the chemotherapeutic effect and reduced the unwanted side-effects of MIT.
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Affiliation(s)
- Yu Wang
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, P.R. China
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7
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Wiklund M. Acoustofluidics 12: Biocompatibility and cell viability in microfluidic acoustic resonators. LAB ON A CHIP 2012; 12:2018-28. [PMID: 22562376 DOI: 10.1039/c2lc40201g] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Manipulation of biological cells by acoustic radiation forces is often motivated by its improved biocompatibility relative to alternative available methods. On the other hand, it is well known that acoustic exposure is capable of causing damage to tissue or cells, primarily due to heating or cavitation effects. Therefore, it is important to define safety guidelines for the design and operation of the utilized devices. This tutorial discusses the biocompatibility of devices designed for acoustic manipulation of mammalian cells, and different methods for quantifying the cell viability in such devices.
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Affiliation(s)
- Martin Wiklund
- Department of Applied Physics, Royal Institute of Technology, SE-10691, Stockholm, Sweden.
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Louisnard O. A simple model of ultrasound propagation in a cavitating liquid. Part II: Primary Bjerknes force and bubble structures. ULTRASONICS SONOCHEMISTRY 2012; 19:66-76. [PMID: 21764349 DOI: 10.1016/j.ultsonch.2011.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 06/14/2011] [Accepted: 06/16/2011] [Indexed: 05/03/2023]
Abstract
In a companion paper, a reduced model for propagation of acoustic waves in a cloud of inertial cavitation bubbles was proposed. The wave attenuation was calculated directly from the energy dissipated by a single bubble, the latter being estimated directly from the fully nonlinear radial dynamics. The use of this model in a mono-dimensional configuration has shown that the attenuation near the vibrating emitter was much higher than predictions obtained from linear theory, and that this strong attenuation creates a large traveling wave contribution, even for closed domain where standing waves are normally expected. In this paper, we show that, owing to the appearance of traveling waves, the primary Bjerknes force near the emitter becomes very large and tends to expel the bubbles up to a stagnation point. Two-dimensional axi-symmetric computations of the acoustic field created by a large area immersed sonotrode are also performed, and the paths of the bubbles in the resulting Bjerknes force field are sketched. Cone bubble structures are recovered and compare reasonably well to reported experimental results. The underlying mechanisms yielding such structures is examined, and it is found that the conical structure is generic and results from the appearance a sound velocity gradient along the transducer area. Finally, a more complex system, similar to an ultrasonic bath, in which the sound field results from the flexural vibrations of a thin plate, is also simulated. The calculated bubble paths reveal the appearance of other commonly observed structures in such configurations, such as streamers and flare structures.
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Affiliation(s)
- O Louisnard
- Centre RAPSODEE, FRE CNRS 3213, Université de Toulouse, Ecole des Mines d'Albi, 81013 Albi Cedex 09, France.
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9
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Xi X, Cegla FB, Lowe M, Thiemann A, Nowak T, Mettin R, Holsteyns F, Lippert A. Study on the bubble transport mechanism in an acoustic standing wave field. ULTRASONICS 2011; 51:1014-1025. [PMID: 21719064 DOI: 10.1016/j.ultras.2011.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/19/2011] [Accepted: 05/31/2011] [Indexed: 05/31/2023]
Abstract
The use of bubbles in applications such as surface chemistry, drug delivery, and ultrasonic cleaning etc. has been enormously popular in the past two decades. It has been recognized that acoustically-driven bubbles can be used to disturb the flow field near a boundary in order to accelerate physical or chemical reactions on the surface. The interactions between bubbles and a surface have been studied experimentally and analytically. However, most of the investigations focused on violently oscillating bubbles (also known as cavitation bubble), less attention has been given to understand the interactions between moderately oscillating bubbles and a boundary. Moreover, cavitation bubbles were normally generated in situ by a high intensity laser beam, little experimental work has been carried out to study the translational trajectory of a moderately oscillating bubble in an acoustic field and subsequent interactions with the surface. This paper describes the design of an ultrasonic test cell and explores the mechanism of bubble manipulation within the test cell. The test cell consists of a transducer, a liquid medium and a glass backing plate. The acoustic field within the multi-layered stack was designed in such a way that it was effectively one dimensional. This was then successfully simulated by a one dimensional network model. The model can accurately predict the impedance of the test cell as well as the mode shape (distribution of particle velocity and stress/pressure field) within the whole assembly. The mode shape of the stack was designed so that bubbles can be pushed from their injection point onto a backing glass plate. Bubble radial oscillation was simulated by a modified Keller-Miksis equation and bubble translational motion was derived from an equation obtained by applying Newton's second law to a bubble in a liquid medium. Results indicated that the bubble trajectory depends on the acoustic pressure amplitude and initial bubble size: an increase of pressure amplitude or a decrease of bubble size forces bubbles larger than their resonant size to arrive at the target plate at lower heights, while the trajectories of smaller bubbles are less influenced by these factors. The test cell is also suitable for testing the effects of drag force on the bubble motion and for studying the bubble behavior near a surface.
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Affiliation(s)
- Xiaoyu Xi
- Department of Mechanical Engineering, Imperial College London, London, UK
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Carugo D, Ankrett DN, Glynne-Jones P, Capretto L, Boltryk RJ, Zhang X, Townsend PA, Hill M. Contrast agent-free sonoporation: The use of an ultrasonic standing wave microfluidic system for the delivery of pharmaceutical agents. BIOMICROFLUIDICS 2011; 5:44108-4410815. [PMID: 22662060 PMCID: PMC3364807 DOI: 10.1063/1.3660352] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/25/2011] [Indexed: 05/02/2023]
Abstract
Sonoporation is a useful biophysical mechanism for facilitating the transmembrane delivery of therapeutic agents from the extracellular to the intracellular milieu. Conventionally, sonoporation is carried out in the presence of ultrasound contrast agents, which are known to greatly enhance transient poration of biological cell membranes. However, in vivo contrast agents have been observed to induce capillary rupture and haemorrhage due to endothelial cell damage and to greatly increase the potential for cell lysis in vitro. Here, we demonstrate sonoporation of cardiac myoblasts in the absence of contrast agent (CA-free sonoporation) using a low-cost ultrasound-microfluidic device. Within this device an ultrasonic standing wave was generated, allowing control over the position of the cells and the strength of the acoustic radiation forces. Real-time single-cell analysis and retrospective post-sonication analysis of insonated cardiac myoblasts showed that CA-free sonoporation induced transmembrane transfer of fluorescent probes (CMFDA and FITC-dextran) and that different mechanisms potentially contribute to membrane poration in the presence of an ultrasonic wave. Additionally, to the best of our knowledge, we have shown for the first time that sonoporation induces increased cell cytotoxicity as a consequence of CA-free ultrasound-facilitated uptake of pharmaceutical agents (doxorubicin, luteolin, and apigenin). The US-microfluidic device designed here provides an in vitro alternative to expensive and controversial in vivo models used for early stage drug discovery, and drug delivery programs and toxicity measurements.
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Tsukamoto A, Higashiyama S, Yoshida K, Watanabe Y, Furukawa KS, Ushida T. Stable cavitation induces increased cytoplasmic calcium in L929 fibroblasts exposed to 1-MHz pulsed ultrasound. ULTRASONICS 2011; 51:982-990. [PMID: 21689836 DOI: 10.1016/j.ultras.2011.05.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 05/23/2011] [Accepted: 05/27/2011] [Indexed: 05/30/2023]
Abstract
An increase in cytoplasmic calcium (Ca(2+) increase) is a second messenger that is often observed under ultrasound irradiation. We hypothesize that cavitation is a physical mechanism that underlies the increase in Ca(2+) in these experiments. To control the presence of cavitation, the wave type was controlled in a sonication chamber. One wave type largely contained a traveling wave (wave type A) while the other wave type largely contained a standing wave (wave type B). Fast Fourier transform (FFT) analysis of a sound field produced by the wave types ascertained that stable cavitation was present only under wave type A ultrasound irradiation. Under the two controlled wave types, the increase in Ca(2+) in L929 fibroblasts was observed with fluorescence imaging. Under wave type A ultrasound irradiation, an increase in Ca(2+) was observed; however, no increase in Ca(2+) was observed under wave type B ultrasound irradiation. We conclude that stable cavitation is involved in the increase of Ca(2+) in cells subjected to pulsed ultrasound.
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Affiliation(s)
- Akira Tsukamoto
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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12
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Kaddur K, Lebegue L, Tranquart F, Midoux P, Pichon C, Bouakaz A. Transient transmembrane release of green fluorescent proteins with sonoporation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2010; 57:1558-1567. [PMID: 20639150 DOI: 10.1109/tuffc.2010.1586] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Microbubbles under ultrasound (US) activation are assumed to induce pore formation in the plasma membrane, causing its permeabilization and hence molecule incorporation from the extracellular environment. In this study, we investigated whether this permeabilization also engenders a transient release of small molecules from the cytosol of mammalian eukaryotic cells under the combined action of US and microbubbles. Using Hela cells stably expressing the enhanced green fluorescent protein (EGFP) gene, the release of EGFP was evaluated by flow cytometry in terms of the percentage of EGFP-positive cells (EGFP + cells) and the mean cell fluorescence intensity (MFI). Sonoporation was performed at 1 MHz, with peak negative pressures ranging from 0.2 to 0.6 MPa, duty cycles of 40% and 75% and a repetition rate of 10 kHz. The results showed that the insonation of Hela-EGFP cells at the peak negative pressure 400 kPa and the 75% duty cycle for 2 min in the presence of microbubbles induced a 60% decrease in both EGFP+ cells percentage and MFI. Our results demonstrate that the reduction of cell fluorescence is attributed to the EGFP release. Most importantly, this EGFP release was not due to lethal effects of sonoporation because the EGFP expression was significantly recovered by 48-h post-insonation. In conclusion, this study demonstrates for the first time a transient release of intracellular molecules produced by the sonoporation process. This controlled release showed the possibility of extracting molecules from the cell cytoplasm through the membrane while preserving cell viability. Taken together, the results obtained in this study reinforce the hypothesis of the transient pore formation mechanism induced by sonoporation.
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Affiliation(s)
- Kadija Kaddur
- Institut Nationalde la Sante et de la Recherche Medicale U930-Centre Nationalde la Recherche Scientifique (CNRS) ERL 3106, Tours, France.
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Bazou D, Davies G, Jiang WG, Coakley T. Rapid Molecular and Morphological Responses of Prostate Cell Lines to Cell–Cell Contact. ACTA ACUST UNITED AC 2009; 13:279-94. [PMID: 17162670 DOI: 10.1080/15419060601077909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cell-cell adhesion in 2-D PZ-HPV-7 prostate epithelial and DU-145 prostate cancer cell aggregates (monolayers), synchronously and rapidly (within 30 s) formed in suspension in an ultrasound trap has been examined over 60 min. The intracellular distributions of the cadherin/catenin complex components for both cell lines were time-dependent and were clearly identifiable as early as 150 s following cell-cell contact in the trap, while equilibrium positions were reached within 60 min following cell-cell contact. The accumulation of E-cadherin at the cell-cell interface was greater for PZ-HPV-7 than for DU-145 cells over 60 min in the trap, with the apparent formation of adherens junctions over that time scale in PZ-HPV-7 but not in DU-145 cells. The amounts of F-actin, alpha-, beta-, and gamma-catenins recruited to the cell-cell interface of PZ-HPV-7 cells were on average 2.4 times higher than those of DU-145 cells. The ability of different cell types to spread along neighboring cells was 1.5-fold greater for the PZ-HPV-7 than for the DU-145 cells. These results, discussed also in the context of earlier studies of cell adhesion in an ultrasound trap, characterize a reduced adhesiveness of DU-145 cells compared to PZ-HPV-7 cells.
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Affiliation(s)
- Despina Bazou
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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14
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Bazou D. Biochemical properties of encapsulated high-density 3-D HepG2 aggregates formed in an ultrasound trap for application in hepatotoxicity studies. Cell Biol Toxicol 2009; 26:127-41. [DOI: 10.1007/s10565-009-9123-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 03/11/2009] [Indexed: 12/24/2022]
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Buldakov MA, Hassan MA, Zhao QL, Feril LB, Kudo N, Kondo T, Litvyakov NV, Bolshakov MA, Rostov VV, Cherdyntseva NV, Riesz P. Influence of changing pulse repetition frequency on chemical and biological effects induced by low-intensity ultrasound in vitro. ULTRASONICS SONOCHEMISTRY 2009; 16:392-397. [PMID: 19022698 DOI: 10.1016/j.ultsonch.2008.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 09/18/2008] [Accepted: 10/08/2008] [Indexed: 05/27/2023]
Abstract
This study was undertaken to examine ultrasound (US) mechanisms and their impact on chemical and biological effects in vitro as a function of changing pulse repetition frequency (PRF) from 0.5 to 100Hz using a 1MHz-generator at low-intensities and 50% duty factor (DF). The presence of inertial cavitation was detected by electron paramagnetic resonance (EPR) spin-trapping of hydroxyl radicals resulting from sonolysis of water. Non-cavitational effects were evaluated by studying the extent of sucrose hydrolysis measured by UV spectrophotometry. Biological effects were assessed by measuring the extent of cell killing and apoptosis induction in U937 cells using Trypan blue dye exclusion test and flow cytometry, respectively. The results indicate significant PRF dependence with respect to hydroxyl radical formation, cell killing and apoptosis induction. The lowest free radical formation and cell killing and the highest cell viability were found at 5Hz (100ms pulse duration). On the other hand, no correlation was found between sucrose hydrolysis and PRF. To our knowledge, this is the first report to be devoted to study the impact of low PRFs at low-intensities on US-induced chemical and biological effects and the mechanisms involved. This study has introduced the role of "US streaming" (convection); a forgotten factor in optimization studies, and explored its importance in comparison to standing waves.
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Affiliation(s)
- Mikhail A Buldakov
- Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
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16
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Bazou D, Coakley W, Hayes A, Jackson S. Long-term viability and proliferation of alginate-encapsulated 3-D HepG2 aggregates formed in an ultrasound trap. Toxicol In Vitro 2008; 22:1321-31. [DOI: 10.1016/j.tiv.2008.03.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 03/28/2008] [Accepted: 03/29/2008] [Indexed: 11/27/2022]
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17
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Sboros V. Response of contrast agents to ultrasound. Adv Drug Deliv Rev 2008; 60:1117-36. [PMID: 18486270 DOI: 10.1016/j.addr.2008.03.011] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 03/04/2008] [Indexed: 11/29/2022]
Abstract
Microbubbles are used as ultrasonic contrast agents that enhance the ultrasound signals of the vascular bed. The recent development of site-targeted microbubbles opened up the possibility for molecular imaging as well as localised drug and gene delivery. Initially the microbubbles' physical properties and their response to the ultrasound beam were not fully understood. However, the introduction of fast acquisition microscopy has allowed the observation of the microbubble behaviour in the presence of ultrasound. In addition, acoustical techniques can determine the scatter of single microbubbles. Sonoporation experiments promise high-specificity drug and gene delivery, but the responsible physical mechanisms, particularly for in vivo applications, are not fully understood. An improvement of microbubble technology may address variability related problems in both imaging and drug/gene delivery.
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Affiliation(s)
- Vassilis Sboros
- Medical Physics, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
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18
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Erpelding TN, Hollman KW, O'Donnell M. Bubble-based acoustic radiation force using chirp insonation to reduce standing wave effects. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:263-9. [PMID: 17306697 PMCID: PMC1995022 DOI: 10.1016/j.ultrasmedbio.2006.07.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 07/18/2006] [Accepted: 07/27/2006] [Indexed: 05/11/2023]
Abstract
Bubble-based acoustic radiation force can measure local viscoelastic properties of tissue. High intensity acoustic waves applied to laser-generated bubbles induce displacements inversely proportional to local Young's modulus. In certain instances, long pulse durations are desirable but are susceptible to standing wave artifacts, which corrupt displacement measurements. Chirp pulse acoustic radiation force was investigated as a method to reduce standing wave artifacts. Chirp pulses with linear frequency sweep magnitudes of 100, 200 and 300 kHz centered around 1.5 MHz were applied to glass beads within gelatin phantoms and laser-generated bubbles within porcine lenses. The ultrasound transducer was translated axially to vary standing wave conditions, while comparing displacements using chirp pulses and 1.5 MHz tone burst pulses of the same duration and peak rarefactional pressure. Results demonstrated significant reduction in standing wave effects using chirp pulses, with displacement proportional to acoustic intensity and bubble size.
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Affiliation(s)
- Todd N Erpelding
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
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19
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Paliwal S, Mitragotri S. Ultrasound-induced cavitation: applications in drug and gene delivery. Expert Opin Drug Deliv 2006; 3:713-26. [PMID: 17076594 DOI: 10.1517/17425247.3.6.713] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Ultrasound, which has been conventionally used for diagnostics until recently, is now being extensively used for drug and gene delivery. This transformation has come about primarily due to ultrasound-mediated acoustic cavitation - particularly transient cavitation. Acoustic cavitation has been used to facilitate the delivery of small molecules, as well as macromolecules, including proteins and DNA. Controlled generation of cavitation has also been used for targeting drugs to diseased tissues, including skin, brain, eyes and endothelium. Ultrasound has also been employed for the treatment of several diseases, including thromboembolism, arteriosclerosis and cancer. This review provides a detailed account of mechanisms, current status and future prospects of ultrasonic cavitation in drug and gene delivery applications.
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Affiliation(s)
- Sumit Paliwal
- University of California, Department of Chemical Engineering, Santa Barbara, CA 93106, USA.
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20
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Bazou D, Dowthwaite GP, Khan IM, Archer CW, Ralphs JR, Coakley WT. Gap junctional intercellular communication and cytoskeletal organization in chondrocytes in suspension in an ultrasound trap. Mol Membr Biol 2006; 23:195-205. [PMID: 16754362 DOI: 10.1080/09687860600555906] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Particles or cells suspended in an appropriately designed ultrasound standing wave field can be aggregated at a node to form a single monolayer in a plane that can be interrogated microscopically. The approach is applied here to investigate the temporal development of F-actin and Cx43 distribution and of gap junctional intercellular communication in 2-D chondrocyte aggregates (monolayers) rapidly and synchronously formed and held in suspension in an ultrasound trap. Development of the F-actin cytoskeleton in the confluent single layer of 'cuboidal' cells forming the aggregate was completed within 1 h. Chondrocytes levitated in the trap synchronously formed functional gap junctions (as assessed by CMFDA dye transfer assays) in less than 1 h of initiation of cell-cell contact in the trap. It was shown that Cx43 gene expression was retained in isolated chondrocytes in suspension. Preincubation of cells with the protein synthesis inhibitor cycloheximide caused a six-fold decrease in Cx43 accumulation (as assessed by immunofluorescence) at the interfaces of chondrocytes in the aggregate. It is shown that the ultrasound trap provides an approach to studying the early stages of cytoskeletal and gap junction development as cells progress from physical aggregation, through molecular adhesion, to display the intracellular consequences of receptor interactions.
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Affiliation(s)
- Despina Bazou
- Cardiff University, School of Biosciences, Cardiff, Wales, UK
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21
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Wang B, Zang WJ, Wang M, Ai H, Wang YW, Li YP, He GS, Wang L, Yu XJ. Prolonging the ultrasound signal enhancement from thrombi using targeted microbubbles based on sulfur-hexafluoride-filled gas. Acad Radiol 2006; 13:428-33. [PMID: 16554222 DOI: 10.1016/j.acra.2005.11.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 11/15/2005] [Accepted: 11/15/2005] [Indexed: 10/24/2022]
Abstract
RATIONALE AND OBJECTIVES The objective of this study is to develop and characterize new microbubbles based on lipids and sulfur hexafluoride (SF6) for targeting thrombi as an improved ultrasound contrast agent. MATERIALS AND METHODS Bioconjugate ligands were inserted into the lipid-coated membranes of SF6 gas microbubbles, and their physicochemical properties were determined. Diagnostic efficacies of SF6-filled microbubbles and the contrast agent SonoVue (Bracco Imaging, Geneve, Switzerland) were compared in dogs. RESULTS Suspensions of lyophilized powder were reconstituted by injecting saline containing 3.1 x 10(8) SF6 microbubbles/mL with a mean diameter of 4.4 microm. More than 90% of microbubbles had diameters between 1 and 10 microm. After reconstitution, echogenicity and microbubble characteristics were unchanged for 8 hours. Targeted microbubbles increased the echogenicity of thrombi significantly and provided a longer period of optimal signal enhancement compared with nontargeted microbubbles. CONCLUSIONS Our thrombus-targeting microbubble contrast agent shows high echogenicity and stability and thereby enhances the visualization of intravascular thrombi and prolongs the duration of the diagnostic window.
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Affiliation(s)
- Bing Wang
- Department of Pathology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China
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22
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Khanna S, Hudson B, Pepper CJ, Amso NN, Coakley WT. Fluorescein isothiocynate-dextran uptake by chinese hamster ovary cells in a 1.5 MHz ultrasonic standing wave in the presence of contrast agent. ULTRASOUND IN MEDICINE & BIOLOGY 2006; 32:289-95. [PMID: 16464674 DOI: 10.1016/j.ultrasmedbio.2005.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 10/24/2005] [Accepted: 11/03/2005] [Indexed: 05/06/2023]
Abstract
Uptake of fluorescein isothiocynate-dextran (FITC-dextran) by Chinese hamster ovary cells was studied after exposure to ultrasonic standing wave (USW) in presence of Optison, an ultrasound contrast agent. Confluent Chinese hamster ovary cells were harvested and suspended in phosphate-buffered saline + 0.1% bovine serum albumin containing FITC-dextran (10, 40, and 500 kDa) at 10 microM final concentration. The suspension was seeded with contrast agent (75 microL/mL) and exposed to a 1.5 MHz USW system at acoustic pressures ranging from 0.98 to 4.2 MPa. Macromolecular uptake was assessed by fluorescent microscopy and quantified by flow cytometry 10 min after exposure. FITC-dextran positive cells, as assessed by flow cytometry, were 1 +/- 0.05% and 2.58 +/- 0.27% for acoustic pressures of 1.96 and 4.2 MPa, respectively (p = 0.006). Fluorescent microscopy indicated a degree of macromolecular loading at 0.98 MPa with 46% of peripherally FITC-dextran- and/or propidium iodide-stained cells coincident with the appearance of significant frequency (f0/2 and 2 f0) emission signals. At higher pressures, high macromolecular loading with 6% peripherally stained cells at 1.96 MPa was associated with lower order emission signals and white noise. The study conclusively demonstrates macromolecular loading in an USW, a significantly higher macromolecular loading at higher pressures and indicates potential of emission signals for a feedback loop to control the acoustic power outputs and fine-tune the biologic effects associated with sonoporation.
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Affiliation(s)
- Sanjay Khanna
- Department of Obstetrics and Gynaecology, Wales College of Medicine, Heath Park, Cardiff, UK
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23
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Kuznetsova LA, Martin SP, Coakley WT. Sub-micron particle behaviour and capture at an immuno-sensor surface in an ultrasonic standing wave. Biosens Bioelectron 2005; 21:940-8. [PMID: 16257663 DOI: 10.1016/j.bios.2005.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Revised: 02/09/2005] [Accepted: 02/22/2005] [Indexed: 11/21/2022]
Abstract
The capture of 200 nm biotinylated latex beads from suspensions of concentration 10(7) to 2.5 x 10(8) particle/ml on an immuno-coated surface of the acoustic reflector in an ultrasound standing wave (USW) resonator has been studied while the acoustic pathlength was less than one half wavelength (lambda/2). The particles were delivered to the reflector's surface by acoustically induced flow. The capture dependencies on suspension concentration, duration of experiments and acoustic pressure have been established at 1.09, 1.46 and 1.75 MHz. Five-fold capture increase has been obtained at 1.75 MHz in comparison to the control (no ultrasound) situation. The contrasting behaviours of 1, 0.5 and 0.2 mum fluorescent latex beads in a lambda/4 USW resonator at 1.46 MHz have been characterized. The particle movements were observed with an epi-fluorescent microscope and the velocities of the particles were measured by particle image velocimetry (PIV). The experiments showed that whereas the trajectories of 1 mum particles were mainly affected by the direct radiation force, 0.5 mum particles were influenced both by the radiation force and acoustic streaming. The 0.2 mum latex beads followed acoustic streaming in the chamber and were not detectably affected by the radiation force. The streaming-associated behaviour of the 200 nm particles has implications for enhanced immunocapture of viruses and macromolecules (both of which are also too small to experience significant acoustic radiation force).
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24
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Lee YH, You JO, Peng CA. Retroviral transduction of adherent cells in resonant acoustic fields. Biotechnol Prog 2005; 21:372-6. [PMID: 15801773 DOI: 10.1021/bp0496427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ultrasound-induced cavitation has been extensively used to enhance the efficiency of nonviral-based gene delivery. Although such unique mechanical force could possibly augment the efficacy of retrovirus-mediated gene transfer, we harnessed an alternative approach, a resonant acoustic field, to facilitate the retroviral transduction rate. NIH 3T3 fibroblast cells suspended in a culture well and mixed with ecotropic retroviruses were co-treated with megahertz resonant acoustic fields (RAF). Suspended NIH 3T3 cells under RAF treatment agglomerated at acoustic nodal planes by primary radiation force within a short exposure time. These first arrived and agglomerated cells formed bands as nucleating sites for nanometer-sized ecotropic retroviruses circulated between nodal planes to attach on and thereby increased cell-virus encounters. According to the neomycin-resistant colony assay, 2-fold increment of retroviral transduction rate was obtained by exposing cells and retroviruses in the RAF for 6 min in the presence of 8 microg/mL Polybrene.
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Affiliation(s)
- Yu-Hsiang Lee
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089, USA
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25
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Rouffiac V, Lavisse S, Bidault F, Paci A, Péronneau P, Roche A, Lassau N. [Validation of a new methodology for characterizing ultrasound contrast agents (UCA)]. ACTA ACUST UNITED AC 2005; 86:325-34. [PMID: 15908873 DOI: 10.1016/s0221-0363(05)81362-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Validation of an experimental ultrasound system on erythrocyte suspensions with variable levels of aggregation and application to the echogenicity quantification of UCA under quasi-physiologic flow conditions. MATERIALS AND METHODS. The system is constituted with a Couette cell with variable applied shear rates, an ultrasound emitter/receiver and a digital scope for radio-frequency signal acquisition. Ultrasound indices (UI) were defined for the two experimental established protocols based on the gold standard laser methodology. Washed red cells with or without variable Dextran 70 kD concentrations were used to simulate a wide particle size range. A preliminary application to UCA was conducted with Levovist for calibration of the system. RESULTS For each protocol, applied ten times on identical whole blood samples, a student t-test revealed no significant variation for all UI. Results on washed red cells were in good agreement with Rayleigh's theory of ultrasound backscattering. Significant correlations were obtained between laser and UI for washed red cells with different Dextran concentrations. An elevation of 12.13 dB in backscattered intensity was obtained after addition of Levovist. CONCLUSION The constituted Couette system allowed reproducible and accurate echogenicity quantification of small scatterers such as UCA in quasi-physiologic blood flow conditions.
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Affiliation(s)
- V Rouffiac
- Laboratoire d'Imagerie du Petit Animal, Institut Gustave Roussy.
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26
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Bazou D, Kuznetsova LA, Coakley WT. Physical enviroment of 2-D animal cell aggregates formed in a short pathlength ultrasound standing wave trap. ULTRASOUND IN MEDICINE & BIOLOGY 2005; 31:423-30. [PMID: 15749566 DOI: 10.1016/j.ultrasmedbio.2004.12.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2004] [Revised: 11/23/2004] [Accepted: 12/02/2004] [Indexed: 05/10/2023]
Abstract
2-D mammalian cell aggregates can be formed and levitated in a 1.5 MHz single half wavelength ultrasound standing wave trap. The physical environment of cells in such a trap has been examined. Attention was paid to parameters such as temperature, acoustic streaming, cavitation and intercellular forces. The extent to which these factors might be intrusive to a neural cell aggregate levitated in the trap was evaluated. Neural cells were exposed to ultrasound at a pressure amplitude of 0.54 MPa for 30 s; a small aggregate had been formed at the center of the trap. The pressure amplitude was then decreased to 0.27 MPa for 2 min, at which level the aggregation process continued at a slower rate. The pressure amplitude was then decreased to 0.06 MPa for 1 h. Temperature measurements that were conducted in situ with a 200 microm thermocouple over a 30 min period showed that the maximum temperature rise was less than 0.5 K. Acoustic streaming was measured by the particle image velocimetry method (PIV). It was shown that the hydrodynamic stress imposed on cells by acoustic streaming is less than that imposed by gentle preparative centrifugation procedures. Acoustic spectrum analysis showed that cavitation activity does not occur in the cell suspensions sonicated at the above pressures. White noise was detected only at a pressure amplitude of 1.96 MPa. Finally, it was shown that the attractive acoustic force between ultrasonically agglomerated cells is small compared with the normal attractive van der Waals force that operates at close cell surface separations. It is concluded that the standing wave trap operates only to concentrate cells locally, as in tissue, and does not modify the in vitro expression of surface receptor interactions.
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Affiliation(s)
- Despina Bazou
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
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27
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Kuznetsova LA, Khanna S, Amso NN, Coakley WT, Doinikov AA. Cavitation bubble-driven cell and particle behavior in an ultrasound standing wave. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2005; 117:104-112. [PMID: 15704403 DOI: 10.1121/1.1835503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The behavior of human erythrocytes and 1-microm-diameter fluorescent latex beads in the presence of Optison contrast agent in a single half-wavelength (lambda/2) ultrasound standing wave (USSW) resonator has been studied. The particle movements were observed with an epi-fluorescent microscope and the velocity of the particles and cells was measured by particle image velocimetry (PIV). Acoustic emissions were monitored with a microphone and a spectrum analyzer. Optison contrast agent disintegrated immediately on exposure to ultrasound of 0.98-MPa acoustic pressure amplitude or higher in a chamber driven at its resonance frequency of 1.56 MHz. A discrete cloud of active microbubbles, detected at the pressure node plane, disappeared gradually and was completely lost within 15 s. The microscopy showed three-dimensional regions of circulation of both 1-microm tracer particles and erythrocytes in planes perpendicular to the pressure node plane. A numerical simulation showed that, for parameters that conform to the experimental conditions, a bubble of a subresonance size moves towards and translates about a pressure node plane. This result is in agreement with the experimental observation that the particle and cell circulation is induced by the presence and/or translational motion of microbubbles at the pressure node plane.
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Affiliation(s)
- Larisa A Kuznetsova
- School of Biosciences, Cardiff University, Cardiff CF10 3TL, United Kingdom.
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28
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Stride E, Saffari N. Theoretical and experimental investigation of the behaviour of ultrasound contrast agent particles in whole blood. ULTRASOUND IN MEDICINE & BIOLOGY 2004; 30:1495-509. [PMID: 15588960 DOI: 10.1016/j.ultrasmedbio.2004.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Revised: 09/04/2004] [Accepted: 09/16/2004] [Indexed: 05/21/2023]
Abstract
The majority of the existing models for the behaviour of ultrasound (US) contrast agents consider a single contrast agent particle (CAP) surrounded by an infinite, homogeneous and Newtonian fluid. In vivo, however, CAPs are suspended within the confines of blood vessels, in fluid containing both other CAPs and a high volume fraction of cells of comparable size. The aim of this work was to investigate the influence of blood cells upon CAP acoustic response to determine how existing models should be modified for the purposes of improving CAP design. A new model for a CAP surrounded by a cluster of cells was derived and solved numerically. Broadband US attenuation measurements were then made in suspensions of Optison (Amersham PLC, Bucks, UK) in plasma and in whole blood. Both the theoretical and experimental results indicate that the presence of blood cells has a relatively small effect upon CAP dynamics and hence acoustic response. This implies that it is justifiable to model blood as homogeneous and Newtonian for the purposes of CAP design.
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Affiliation(s)
- Eleanor Stride
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK.
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29
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Coakley WT, Bazou D, Morgan J, Foster GA, Archer CW, Powell K, Borthwick KAJ, Twomey C, Bishop J. Cell–cell contact and membrane spreading in an ultrasound trap. Colloids Surf B Biointerfaces 2004; 34:221-30. [PMID: 15261061 DOI: 10.1016/j.colsurfb.2004.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 11/05/2003] [Accepted: 01/12/2004] [Indexed: 11/28/2022]
Abstract
An ultrasonic standing wave trap [Langmuir 19 (2003) 3635] in which the morphologies of 2-D latex-microparticle aggregates, forming a pressure node plane, were characterised has been applied here to different cell suspensions with increasing order of specificity of cross-linking molecule, i.e. polylysine with chondrocytes; wheat germ agglutinin (WGA) with erythrocytes and surface receptors on neural cells. The outcome of initial cell-cell contact, i.e. whether the cells stuck at the point of contact (collision efficiency = 1) or rolled around each other (collision efficiency = 0), was monitored in situ by video-microscopy. The perimeter fractal dimensions (FD) of 2-D hexagonally symmetric, closely packed aggregates of control erythrocytes and chondrocytes were 1.16 and 1.18, respectively while those for the dendrititc aggregates formed initially by erythrocytes in 0.5microg/ml WGA and chondrocytes in 20 microg/ml polylysine were 1.49 and 1.66. The FDs for control and molecularly cross-linked cells were typical of reaction-limited aggregation (RLA) and transport diffusion-limited aggregation (DLA), respectively. The FDs of the aggregates of cross-linked cells decreased with time to give more closely packed aggregates without clear hexagonal symmetry. Suspensions of neural cells formed dendritic aggregates. Spreading of inter-cellular membrane contact area occurred over 15 min for both erythrocyte and neural cell dendritic aggregates. The potential of the technique to characterise and control the progression of cell adhesion in suspension away from solid substrata is discussed.
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Affiliation(s)
- W T Coakley
- School of Biosciences, Main Building, Cardiff University, Cardiff CF10 3TL, UK.
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30
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Morgan J, Spengler JF, Kuznetsova L, Coakley WT, Xu J, Purcell WM. Manipulation of in vitro toxicant sensors in an ultrasonic standing wave. Toxicol In Vitro 2004; 18:115-20. [PMID: 14630069 DOI: 10.1016/j.tiv.2003.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Multi-cellular spheroids are increasingly employed as in vitro sensors of toxicants and a single spheroid can be used as a test object. An ultrasonic standing wave trap (USWT) can hold small particles in a medium-flowing system. This study investigated the conditions for holding HepG2 spheroids in an USWT and its relevance to use in toxicity testing. It can take many hours to reach a detectable end point of cell damage in a standard cellular in vitro toxicant assay and the process might be accelerated through increased sample flow past the spheroid. A USWT was employed here to levitate and hold HepG2 spheroids stationary against a flow of 3 mm s(-1) when the acoustic pressure amplitude is 1.9 MPa. The ultrasonic drive frequency was 1.64 MHz. Acoustic microstreaming in the standing wave chamber generated 1 mm s(-1) flow past a levitated spheroid-scale (80 microm diameter) latex particle in the absence of sample through-flow. The conditions required to form aggregates of cells of a HepG2 cell line in a single half wavelength ultrasonic standing wave mini-chambers are also described here. It is argued that the manipulation capabilities demonstrated may have potential in increasing the efficiency of in vitro toxicant detection by spheroids. Preliminary, visual (unquantified) fluorescence microscopy observations of spheroids levitated in the standing wave in the presence of the toxicant DL-propranolol do suggest accelerated loss of viability compared with controls.
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Affiliation(s)
- J Morgan
- School of Biosciences, Cardiff University, Museum Place, CF10 3TL, Wales, UK
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