Monitoring motility, spreading, and mortality of adherent insect cells using an impedance sensor

An emerging sensor technology referred to as electric cell-substrate impeda nce sensing (ECIS) has been extended for monitoring the behavior of insect cells including attachment, motility, and mortality. In ECIS, adherent cell s were cultured on an array of eight small gold electrodes deposited on the bottom of tissue culture wells and immersed in a culture medium. Upon the attachment and spreading of cells on the gold electrode, the impedance incr eased because the cells acted as insulating particles to restrict the curre nt flow. Experimental data revealed that insect cells interacted differentl y with various proteins used to precoat the gold electrode with concanavali n A as the best promoter to accelerate the rate of cell attachment. After t he cells were fully spread, the measured impedance continued to fluctuate t o reflect the constant motion and metabolic activity of the cells. As the c ell behavior was sensitive to external chemicals, the applicability of ECIS for inhibition assays was demonstrated with HgCl2, trinitrotoluene, trinit robenzene (TNB), and 2-amino-4,6-dinitrotoluene as model systems. Unlike co nventional assays, the quantitative data obtained in this study are taken i n real time and in a continuous fashion to depict cell motility and mortali ty.