Impedimetric Biosensor System for the On-line Analysis of Stimulated Neuronal Cells Embedded in Gel Matrices

In this contribution a novel biosensor system for the on-line analysis of stimulated neuronal cells embedded in gel matrices is presented. The system enables electrical impedance measurement of gel films in the range of 10 to 110 MHz, while cell culture medium is continuously flowing in parallel to the sensor surface. A technique for the immobilization of cells in bactoagar and the fabrication of thin films inside an impedimetric sensor was developed. The biosensor system was applied for the characterization of Neuro-2a neuroblastoma (N2a) cells in terms of dielectric and conductive properties. In addition, the kinetics of acetylcholine receptor triggering was studied by means of on-line impedance analysis. Even at frequencies >= 10 MHz, the cellular response is dominated by the conductive properties of the gel matrix, while measured kinetics are mainly limited by diffusion. Cell viability tests based on a modified MTT assay were conducted in parallel. Experimental results revealed that cell viability in the sensor remains stable at least for a period of 24 h.