title: Electrokinetic measurements of dielectric properties of membrane for apoptotic HL-60 cells on chip-based device.
abstract: The specific membrane capacitance and conductance of mammalian cells reflect the surface morphological complexities and barrier functions of cell membrane, respectively, and could potentially respond to cell physiological and pathological changes in a measurable manner. In this study, an electrokinetic system was developed by using negative dielectrophoretic force (nDEP force) assisted positioning and electroroation (ROT) measurement. Numerical simulations regarding the geometric model of the electrode were performed primarily for the electric field analysis. The dielectric responses of membrane for apoptotic HL-60 cells induced by bufalin were detected. The membrane capacitance of the cells was found to fall from an initial value of 15.6 +/- 0.9 mF/cm(2) to 6.4 +/- 0.6 mF/cm(2) after a 48 h treatment with 10 nM bufalin. However, the membrane conductance remained almost constant at (2.25 +/- 1.1) x 10(3) S/m(2) during the first 12 h of bufalin treatment and then increased distinctly to (4.2 +/- 1.3) x 10(3) S/m(2) thereafter. Scan electron microscopy (SEM) studies of the cells revealed a decreased complexity in cell membrane morphology following bufalin treatments, suggesting that the observed changes in the membrane capacitance was dominated by the alterations of cell surface structures. The results demonstrate that the ROT technique gives a quantitative analysis of the toxic damage by chemicals to cells and can be exploited in the testing and development of new pharmaceuticals and active cell agents.
authors.affiliation: Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Chengjun
authors.initials: C
authors.lastname: Huang
authors.forename: Ailiang
authors.initials: A
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
mesh_terms: D000818:Animals; D017209:Apoptosis; D002452:Cell Count / Q000295:instrumentation / Q000379:methods; D002462:Cell Membrane / Q000528:radiation effects*; D025802:Electric Capacitance; D017097:Electric Impedance; D004586:Electrophoresis / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005434:Flow Cytometry / Q000295:instrumentation* / Q000379:methods; D018922:HL-60 Cells; D006801:Humans; D007700:Kinetics; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods