A porous membrane-based microelectroanalytical technique for evaluating locally stimulated culture cells

We have investigated a technique for the local stimulation of cultured cells by considering the combination of electrochemical bioassay using scanning electrochemical microscopy (SECM). The device for the local stimulation was prepared by binding a permeable substrate made of a microporous alumina membrane (pore size 0.02 μm, surface porosity 50%) and a micromask made of an elastomeric poly-(dimethylsiloxane) (PDMS) (40 μm thickness having a 50 μm diameter hole). HeLa cells were cultured on the membrane and a chemical (ethanol, in this study) was locally delivered from the opposite phase. The live-dead staining experiments showed that the ethanol stimulation was applied only to the cells in the area defined by the micromask. The electroactive species around the stimulated and non-stimulated cells were simultaneously measured by SECM using a 5.0 μm-radius Pt microelectrode as a probe at -0.5 V versus Ag/AgCl and comparatively evaluated.