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Tupper LL, Keese CR, Matteson DS. Classifying contaminated cell cultures using time series features. J Appl Stat 2023; 51:1210-1226. [PMID: 38628445 PMCID: PMC11018005 DOI: 10.1080/02664763.2023.2248413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 07/30/2023] [Indexed: 04/19/2024]
Abstract
We examine the use of time series data, derived from Electric Cell-substrate Impedance Sensing (ECIS), to differentiate between standard mammalian cell cultures and those infected with a mycoplasma organism. With the goal of easy visualization and interpretation, we perform low-dimensional feature-based classification, extracting application-relevant features from the ECIS time courses. We can achieve very high classification accuracy using only two features, which depend on the cell line under examination. Initial results also show the existence of experimental variation between plates and suggest types of features that may prove more robust to such variation. Our paper is the first to perform a broad examination of ECIS time course features in the context of detecting contamination; to combine different types of features to achieve classification accuracy while preserving interpretability; and to describe and suggest possibilities for ameliorating plate-to-plate variation.
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De Leon SE, Cleuren L, Oo ZY, Stoddart PR, McArthur SL. Extending In-Plane Impedance Measurements from 2D to 3D Cultures: Design Considerations. Bioengineering (Basel) 2021; 8:11. [PMID: 33450860 PMCID: PMC7828367 DOI: 10.3390/bioengineering8010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 11/22/2022] Open
Abstract
Three-dimensional (3D) cell cultures have recently emerged as tools for biologically modelling the human body. As 3D models make their way into laboratories there is a need to develop characterisation techniques that are sensitive enough to monitor the cells in real time and without the need for chemical labels. Impedance spectroscopy has been shown to address both of these challenges, but there has been little research into the full impedance spectrum and how the different components of the system affect the impedance signal. Here we investigate the impedance of human fibroblast cells in 2D and 3D collagen gel cultures across a broad range of frequencies (10 Hz to 5 MHz) using a commercial well with in-plane electrodes. At low frequencies in both 2D and 3D models it was observed that protein adsorption influences the magnitude of the impedance for the cell-free samples. This effect was eliminated once cells were introduced to the systems. Cell proliferation could be monitored in 2D at intermediate frequencies (30 kHz). However, the in-plane electrodes were unable to detect any changes in the impedance at any frequency when the cells were cultured in the 3D collagen gel. The results suggest that in designing impedance measurement devices, both the nature and distribution of the cells within the 3D culture as well as the architecture of the electrodes are key variables.
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Affiliation(s)
- Sorel E. De Leon
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
| | - Lana Cleuren
- PXL University College, Hasselt University, 3500 Hasselt, Belgium;
| | - Zay Yar Oo
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
| | - Paul R. Stoddart
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
| | - Sally L. McArthur
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
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PEDOT Coated Thick Film Electrodes for In Situ Detection of Cell Adhesion in Cell Cultures. BIOSENSORS-BASEL 2018; 8:bios8040105. [PMID: 30400265 PMCID: PMC6315667 DOI: 10.3390/bios8040105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 01/26/2023]
Abstract
Low temperature cofired ceramics (LTCC) provide a technology for the 3-dimensional integration of sensor arrays into bioreactors covering dimensions of several hundred micrometers. Since optical control in such assemblies is not possible, the in situ detection of cell adhesion on impedance electrodes with high spatial resolution would deliver crucial information. A current limitation is the increasing impedance of microelectrodes with decreasing diameter. This study evaluates the suitability of thick film gold electrodes, pristine and coated with electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT), for the detection of cell adhesion on the electrode surface. The impedance as criterion for cell attachment is measured with a recording system for electroactive cells with the aim of improving usability. Two cell cultures with different adhesion characteristic are used for adhesion assessment on planar test chips. The impedance increase measured on individual PEDOT coated electrodes due to tight contact of cells reaches a factor of 6.8 in cultures of well-adherent HepG2 cells. Less adhered NG108-15 cells produce a maximum impedance increase by a factor of 2.6. Since the electrode impedance is significantly reduced by PEDOT coating, a reduction of the electrode diameter to values below 100 µm and spatially resolved detection is possible. The results encourage further studies using PEDOT coated thick film electrodes as bio-electronic-interfaces. We presume that such miniaturized electrodes are suitable for 3-dimensional recordings in electroactive cell cultures, providing information of local cell adhesion at the same time.
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Lecina M, Sanchez B, Solà C, Prat J, Roldán M, Hernández M, Bragós R, Paredes CJ, Cairó JJ. Structural changes of Arthrospira sp. after low energy sonication treatment for microalgae harvesting: Elucidating key parameters to detect the rupture of gas vesicles. BIORESOURCE TECHNOLOGY 2017; 223:98-104. [PMID: 27788433 DOI: 10.1016/j.biortech.2016.10.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/07/2016] [Accepted: 10/08/2016] [Indexed: 06/06/2023]
Abstract
The buoyancy suppression by low energy sonication (LES) treatment (0.8W·mL-1, 20kHz, 10s) has recently been proposed as an initial harvesting step for Arthrospira sp. This paper aims to describe the structural changes in Arthrospira sp. after LES treatment and to present how these structural changes affect the results obtained by different analytical techniques. Transmission electron microscopy (TEM) micrographs of trichomes evidenced the gas vesicles rupture but also revealed a rearrangement of thylakoids and more visible phycobilisomes were observed. Differences between treated and untreated samples were detected by confocal microscopy, flow cytometry and optical microscopy but not by electrical impedance spectroscopy (EIS). After LES treatment, 2-fold increase in autofluorescence at 610/660nm was measured (phycocyanin/allophycocyanin emission wavelengths) and a ten-fold decrease in side scatter light intensity (due to a reduction of trichome's inner complexity). This was further confirmed by optical microscopy showing changes on trichomes appearance (from wrinkled to smooth).
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Affiliation(s)
- Martí Lecina
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| | - Benjamin Sanchez
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carles Solà
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi Prat
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Mònica Roldán
- Servei de Microscòpia, Universitat Autònoma de Barcelona, Edifici C, Facultat de Ciències, 08193 Bellaterra, Spain
| | - Mariona Hernández
- Dep. Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carlos J Paredes
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi J Cairó
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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Stolwijk JA, Matrougui K, Renken CW, Trebak M. Impedance analysis of GPCR-mediated changes in endothelial barrier function: overview and fundamental considerations for stable and reproducible measurements. Pflugers Arch 2015; 467:2193-218. [PMID: 25537398 PMCID: PMC4480219 DOI: 10.1007/s00424-014-1674-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 12/19/2022]
Abstract
The past 20 years has seen significant growth in using impedance-based assays to understand the molecular underpinning of endothelial and epithelial barrier function in response to physiological agonists and pharmacological and toxicological compounds. Most studies on barrier function use G protein-coupled receptor (GPCR) agonists which couple to fast and transient changes in barrier properties. The power of impedance-based techniques such as electric cell-substrate impedance sensing (ECIS) resides in its ability to detect minute changes in cell layer integrity label-free and in real-time ranging from seconds to days. We provide a comprehensive overview of the biophysical principles, applications, and recent developments in impedance-based methodologies. Despite extensive application of impedance analysis in endothelial barrier research, little attention has been paid to data analysis and critical experimental variables, which are both essential for signal stability and reproducibility. We describe the rationale behind common ECIS data presentation and interpretation and illustrate practical guidelines to improve signal intensity by adapting technical parameters such as electrode layout, monitoring frequency, or parameter (resistance versus impedance magnitude). Moreover, we discuss the impact of experimental parameters, including cell source, liquid handling, and agonist preparation on signal intensity and kinetics. Our discussions are supported by experimental data obtained from human microvascular endothelial cells challenged with three GPCR agonists, thrombin, histamine, and sphingosine-1-phosphate.
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Affiliation(s)
- Judith A Stolwijk
- The SUNY College of Nanoscale Science and Engineering (CNSE), SUNY Polytechnic Institute, State University of New York, 257 Fuller Rd., Albany, NY, 12203, USA
- Applied BioPhysics Inc., Troy, NY, USA
| | - Khalid Matrougui
- Department of Physiological Sciences, East Virginia Medical School, Norfolk, VA, USA
| | | | - Mohamed Trebak
- The SUNY College of Nanoscale Science and Engineering (CNSE), SUNY Polytechnic Institute, State University of New York, 257 Fuller Rd., Albany, NY, 12203, USA.
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Dibao-Dina A, Follet J, Ibrahim M, Vlandas A, Senez V. Electrical impedance sensor for quantitative monitoring of infection processes on HCT-8 cells by the waterborne parasite Cryptosporidium. Biosens Bioelectron 2015; 66:69-76. [DOI: 10.1016/j.bios.2014.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/28/2014] [Accepted: 11/06/2014] [Indexed: 01/07/2023]
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Ramuz M, Hama A, Huerta M, Rivnay J, Leleux P, Owens RM. Combined optical and electronic sensing of epithelial cells using planar organic transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:7083-90. [PMID: 25179835 PMCID: PMC4489338 DOI: 10.1002/adma.201401706] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/28/2014] [Indexed: 05/17/2023]
Abstract
A planar, conducting-polymer-based transistor for combined optical and electronic monitoring of live cells provides a unique platform for monitoring the health of cells in vitro. Monitoring of MDCK-I epithelial cells over several days is shown, along with a demonstration of the device for toxicology studies, of use in future drug discovery or diagnostics applications.
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Affiliation(s)
- Marc Ramuz
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
| | - Adel Hama
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
| | - Miriam Huerta
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
| | - Jonathan Rivnay
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
| | - Pierre Leleux
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
- Aix-Marseille Université, Institut de Neurosciences des Systèmes13005, Marseille, France
- Inserm, UMR_S 110613005, Marseille, France
- Microvitae Technologies, Pôle d’Activité Y. Morandat13120, Gardanne, France
| | - Róisín M Owens
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC880 avenue de Mimet, 13541, Gardanne, France E-mail:
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Sarró E, Lecina M, Fontova A, Solà C, Gòdia F, Cairó J, Bragós R. Electrical impedance spectroscopy measurements using a four-electrode configuration improve on-line monitoring of cell concentration in adherent animal cell cultures. Biosens Bioelectron 2012; 31:257-63. [DOI: 10.1016/j.bios.2011.10.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/13/2011] [Accepted: 10/17/2011] [Indexed: 11/25/2022]
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Ghenim L, Kaji H, Hoshino Y, Ishibashi T, Haguet V, Gidrol X, Nishizawa M. Monitoring impedance changes associated with motility and mitosis of a single cell. LAB ON A CHIP 2010; 10:2546-50. [PMID: 20676434 DOI: 10.1039/c004115g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a device enabling impedance measurements that probe the motility and mitosis of a single adherent cell in a controlled way. The micrometre-sized electrodes are designed for adhesion of an isolated cell and enhanced sensitivity to cell motion. The electrode surface is switched electro-chemically to favour cell adhesion, and single cells are attracted to the electrode using positive dielectrophoresis. Periods of linear variation in impedance with time correspond to the motility of a single cell adherent to the surface estimated at 0.6 μm h(-1). In the course of our study we observed the impedance changes associated with mitosis of a single cell. Electrical measurements, carried out concomitantly with optical observations, revealed three phases, prophase, metaphase and anaphase in the time variation of the impedance during cell division. Maximal impedance was observed at metaphase with a 20% increase of the impedance. We argue that at mitosis, the changes detected were due to the charge density distribution at the cell surface. Our data demonstrate subtle electrical changes associated with cell motility and for the first time with division at the single-cell level. We speculate that this could open up new avenues for characterizing healthy and pathological cells.
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Affiliation(s)
- Lamya Ghenim
- CEA, iRTSV, Laboratoire Biopuces, 17 Rue des Martyrs, 38054 Grenoble, France.
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Newbold C, Richardson R, Millard R, Huang C, Milojevic D, Shepherd R, Cowan R. Changes in biphasic electrode impedance with protein adsorption and cell growth. J Neural Eng 2010; 7:056011. [PMID: 20841637 PMCID: PMC3543851 DOI: 10.1088/1741-2560/7/5/056011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study was undertaken to assess the contribution of protein adsorption and cell growth to increases in electrode impedance that occur immediately following implantation of cochlear implant electrodes and other neural stimulation devices. An in vitro model of the electrode-tissue interface was used. Radiolabelled albumin in phosphate buffered saline was added to planar gold electrodes and electrode impedance measured using a charge-balanced biphasic current pulse. The polarization impedance component increased with protein adsorption, while no change to access resistance was observed. The maximum level of protein adsorbed was measured at 0.5 µg cm(-2), indicating a tightly packed monolayer of albumin molecules on the gold electrode and resin substrate. Three cell types were grown over the electrodes, macrophage cell line J774, dissociated fibroblasts and epithelial cell line MDCK, all of which created a significant increase in electrode impedance. As cell cover over electrodes increased, there was a corresponding increase in the initial rise in voltage, suggesting that cell cover mainly contributes to the access resistance of the electrodes. Only a small increase in the polarization component of impedance was seen with cell cover.
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Reybier K, Ribaut C, Coste A, Launay J, Fabre PL, Nepveu F. Characterization of oxidative stress in Leishmaniasis-infected or LPS-stimulated macrophages using electrochemical impedance spectroscopy. Biosens Bioelectron 2010; 25:2566-72. [DOI: 10.1016/j.bios.2010.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/14/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
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Ribaut C, Reybier K, Reynes O, Launay J, Valentin A, Fabre PL, Nepveu F. Electrochemical impedance spectroscopy to study physiological changes affecting the red blood cell after invasion by malaria parasites. Biosens Bioelectron 2008; 24:2721-5. [PMID: 19167879 DOI: 10.1016/j.bios.2008.12.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 11/28/2008] [Accepted: 12/03/2008] [Indexed: 11/27/2022]
Abstract
The malaria parasite, Plasmodium falciparum, invades human erythrocytes and induces dramatic changes in the host cell. The idea of this work was to use RBC modified electrode to perform electrochemical impedance spectroscopy (EIS) with the aim of monitoring physiological changes affecting the erythrocyte after invasion by the malaria parasite. Impedance cell-based devices are potentially useful to give insight into cellular behavior and to detect morphological changes. The modelling of impedance plots (Nyquist diagram) in equivalent circuit taking into account the presence of the cellular layer, allowed us pointing out specific events associated with the development of the parasite such as (i) strong changes in the host cell cytoplasm illustrated by changes in the film capacity, (ii) perturbation of the ionic composition of the host cell illustrated by changes in the film resistance, (iii) releasing of reducer (lactic acid or heme) and an enhanced oxygen consumption characterized by changes in the charge transfer resistance and in the Warburg coefficient characteristic of the redox species diffusion. These results show that the RBC-based device may help to analyze strategic events in the malaria parasite development constituting a new tool in antimalarial research.
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Affiliation(s)
- Clotilde Ribaut
- Université de Toulouse, UPS, INP, INSA, Laboratoire pharmacochimie des substances naturelles et pharmacophores redox, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
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Juzenas P, Chen W, Sun YP, Coelho MAN, Generalov R, Generalova N, Christensen IL. Quantum dots and nanoparticles for photodynamic and radiation therapies of cancer. Adv Drug Deliv Rev 2008; 60:1600-14. [PMID: 18840487 PMCID: PMC2695009 DOI: 10.1016/j.addr.2008.08.004] [Citation(s) in RCA: 341] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 08/16/2008] [Indexed: 12/18/2022]
Abstract
Semiconductor quantum dots and nanoparticles composed of metals, lipids or polymers have emerged with promising applications for early detection and therapy of cancer. Quantum dots with unique optical properties are commonly composed of cadmium contained semiconductors. Cadmium is potentially hazardous, and toxicity of such quantum dots to living cells, and humans, is not yet systematically investigated. Therefore, search for less toxic materials with similar targeting and optical properties is of further interest. Whereas, the investigation of luminescence nanoparticles as light sources for cancer therapy is very interesting. Despite advances in neurosurgery and radiotherapy the prognosis for patients with malignant gliomas has changed little for the last decades. Cancer treatment requires high accuracy in delivering ionizing radiation to reduce toxicity to surrounding tissues. Recently some research has been focused in developing photosensitizing quantum dots for production of radicals upon absorption of visible light. In spite of the fact that visible light is safe, this approach is suitable to treat only superficial tumours. Ionizing radiation (X-rays and gamma rays) penetrate much deeper thus offering a big advantage in treating patients with tumours in internal organs. Such concept of using quantum dots and nanoparticles to yield electrons and radicals in photodynamic and radiation therapies as well their combination is reviewed in this article.
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Affiliation(s)
- Petras Juzenas
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Rikshospitalet University Hospital, Montebello, 0310 Oslo, Norway.
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15
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Ribaut C, Reybier K, Torbiero B, Launay J, Valentin A, Reynes O, Fabre PL, Nepveu F. Strategy of red blood cells immobilisation onto a gold electrode: Characterization by electrochemical impedance spectroscopy and quartz crystal microbalance. Ing Rech Biomed 2008. [DOI: 10.1016/j.rbmret.2007.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Monitoring viral-induced cell death using electric cell-substrate impedance sensing. Biosens Bioelectron 2007; 23:536-42. [PMID: 17826975 DOI: 10.1016/j.bios.2007.06.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 06/11/2007] [Accepted: 06/27/2007] [Indexed: 11/29/2022]
Abstract
Using an electrical measurement known as electric cell-substrate impedance sensing (ECIS), we have recorded the dynamics of viral infections in cell culture. With this technique, cells are cultured on small gold electrodes where the measured impedance mirrors changes in attachment and morphology of cultured cells. As the cells attach and spread on the electrode, the measured impedance increases until the electrode is completely covered. Viral infection inducing cytopathic effect results in dramatic impedance changes, which are mainly due to cell death. In the current study, two different fish cell lines have been used: chinook salmonid embryonic (CHSE-214) cells infected with infectious pancreatic necrosis virus (IPNV) and epithelioma papulosum cyprini (EPC) carp cells infected with infectious hematopoeitic necrosis virus (IHNV). The impedance changes caused by cell response to virus are easily measured and converted to resistance and capacitance. An approximate linear correlation between log of viral titer and time of cell death was determined.
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Cheran LE, Cheung S, Al Chawaf A, Ellis JS, Belsham DD, MacKay WA, Lovejoy D, Thompson M. Label-free detection of neuron–drug interactions using acoustic and Kelvin vibrational fields. Analyst 2007; 132:242-55. [PMID: 17325758 DOI: 10.1039/b615476j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Kelvin and acoustic fields of high-frequency have been employed in the non-invasive investigation of immortalized hypothalamic neurons, in order to assess their response to different concentrations of specific drugs, toxins, a stress-reducing hormone and neurotrophic factors. In an analytical systems biology approach, this work constitutes a first study of living neuron cultures by scanning Kelvin nanoprobe (SKN) and thickness shear mode (TSM) acoustic wave techniques. N-38 hypothalamic mouse neurons were immobilized on the gold electrode of 9 MHz TSM acoustic wave devices and gold-coated slides for study by SKN. The neurons were exposed to the neurochemicals betaseron, forskolin, TCAP, and cerebrolysin. Signals were collected with the TSM in real-time mode, and with the SKN in scanning and real-time modes, as the drugs were applied at biologically significant concentrations. With the TSM, for all drugs, some frequency and resistance shifts were in the same direction, contrary to normal functioning for this type of instrument. Possible mechanisms are presented to explain this behaviour. An oscillatory signal with periodicity of approximately 2 min was observed for some neuron-coated surfaces, where the amplitude of these oscillations was altered upon application of certain neurotrophic factors. These two new techniques present novel and non-invasive electrodeless methods for detecting changes at the cellular level caused by a variety of neuroactive compounds, without killing or destroying the neurons.
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Affiliation(s)
- Larisa-Emilia Cheran
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
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