Optical Single Cell Resolution Cytotoxicity Biosensor Based onSingle Cell Adhesion Dot Arrays

Abstract

Low cost easy to use cell viability tests are needed in the pharmaceutical, biomaterial and environmental industry to measure adverse cellular effects. Herein we present a new methodology to track cell death with high resolution. We achieved dynamic digital quantification of cell viability by simple optical imaging using “Single Cell Adhesion Dot Arrays” (SCADA). Fibronectin (FN) dot arrays were fabricated on cell culture multiwell plates. The dot array was designed to accomodate a single cell on each fibronectin dot. For cytotoxicity measurements, cell-filled SCADA substrates were exposed to K2CrO4, HgSO4 salts and dimethyl sulfoxide (DMSO). Adherent cells commonly detach from the surface when they die. Dynamic monitoring of the toxic effect of DMSO and K2CrO4 was done measuring cell detachment rate during more than 30 hours by quantifying the number of occupied dots in the SCADA array. HgSO4 inhibited cellular detachment from the surface, and cytotoxicity was monitored using Trypan Blue life/death assay directly on the surface. In all cases, the cytotoxicity effects were easily monitored with single cell resolution and the results were comparable to previous reports. Cytotoxicity SCADA tests require only a transparent substrate, with a patterned area of less than 1 mm2 and a reduced number of cells. SCADA enabled dynamic measurements at the highest resolution due to the digital measuring of this methodology. Integrated into microfluidic platforms, SCADA will provide a practical tool that will extent to fundamental research and commercial applications.