Microfabrication and characterization of an ion-selective microelectrode array platform

The design and the fabrication of an ion-selective electrode array platform aimed at in vitro intracellular recording are presented. The platform is composed of two parts: (i) a glass chip with microchannels whose bottom part is patterned with a platinum layer and (ii) a silicon chip in which an array of 50 μm long silicon nitride micropipettes with an inner diameter of 5 μm are structured. The 24 micropipettes are individually filled with a Ca²⁺ selective membrane, based on the neutral ionophore ETH 129. Preliminary tests in Ca²⁺ buffered solutions have shown a linear range from 10⁻⁶ to 0.1 M Ca²⁺ with a sensitivity of 27 mV/decade.