title: Real-time characterization of cytotoxicity using single-cell impedance monitoring.
abstract: Cellular impedance sensors have attracted great attention as a powerful characterization tool for real-time, label-free detection of cytotoxic agents. However, impedance measurements with conventional cell-based sensors that host multiple cells on a single electrode neither provide optimal cell signal sensitivity nor are capable of recording individual cell responses. Here we use a single-cell based platform to monitor cellular impedance on planar microelectrodes to characterize cellular death. In this study, individual cells were selectively patterned on microelectrodes with each hosting one live cell through ligand-mediated natural cell adhesion. Changes in cellular morphology and cell-electrode adherence were monitored after the patterned cells were treated with varying concentrations of hydrogen peroxide, sodium arsenite, and disodium hydrogen arsenate, three potent toxicants related to neurotoxicity and oxidative stress. At low toxicant concentrations, impedance waveforms acquired from individual cells showed variable responses. A time- and concentration-dependent response was seen in the averaged single-cell impedance waveform for all three toxicants. The apoptosis and necrosis characterizations were performed to validate cell impedance results. Furthermore, time constants of apoptosis and necrosis in response to toxicant exposure were analytically established using an equivalent circuit model that characterized the mechanisms of cell death.
authors.affiliation: Department of Materials Science & Engineering, University of Washington, Seattle, Washington 98195-2120, USA.
authors.forename: Fareid
authors.initials: F
authors.lastname: Asphahani
authors.forename: Myo
authors.initials: M
authors.lastname: Thein
authors.forename: Kui
authors.initials: K
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Wood
authors.forename: Sau Shun
authors.initials: SS
authors.lastname: Wong
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Miqin
authors.initials: M
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis; D017097:Electric Impedance; D005434:Flow Cytometry; D008839:Microelectrodes; D059010:Single-Cell Analysis