Silicate sol-gels are chemically inert, exhibit good mechanical and thermal stability, are biocompatible and relatively low-cost . They were shown to inhibit settlement of zoospores . Due to high porosity they are often used for enzyme immobilization for sensors and fuel cell applications. In this work electrodes were coated with porous layers of silicate matrix formed as a result of cross-linking of tetramethoxysilane (TMOS) (Figure ) or tetramethoxysilane and N-Trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMA). The addition of the TMA cation results in higher porosity due to presence of ordered defects . Initial results were similar for both layers, however after just 1 day of incubation in cell culture medium a complete signal loss was observed for the TMA/TMOS modification. For the TMOS modification peaks were significantly reduced but still observable after 3 week of incubation in cell medium. The pH dependence was close to the theoretical value (~60 mV/dec for reduction). It was one of the few modifications that withstood cell culture treatment during the whole time frame of the experiment.