Abstract: A pH sensitive microsensor which comprises a substrate on which a sensor membrane is formed by laser ablation of a target and depositing the target material on the substrate.

Abstract: In a biosensor system for detecting trace compounds resulting from a fire or from plants damaged by destructive insects, a live chemoreceptor is provided for sensing the trace compounds, and a semiconductor component is connected to the chemoreceptor for providing sensor signals when the chemoreceptor senses the presence of trace compounds.

Abstract: Biomaterial such as an enzyme, cell, antigen or antibody is immobilized by covalent bonding to a substrate having an Si.sub.3 N.sub.4 surface containing Si--NH.sub.2 groups that provide reactive NH.sub.2 groups. A heterobifunctional cross-linking agent having an NH.sub.2 -reactive group and a biomaterial-reactive group is reacted with the NH.sub.2 groups of the surface and then with the biomaterial or the heterobifunctional cross-linking agent is reacted with the biomaterial and then with the NH.sub.2 groups of the surface. The Si.sub.3 N.sub.4 surface containing Si--NH.sub.2 groups can be formed by precipitating on a substrate a 10-1000 nm thick Si.sub.3 N.sub.4 layer from a SiH.sub.4 /NH.sub.3 mixture, and providing reactive NH.sub.2 groups on the surface of the layer by subjecting the surface to hydrolyzing cleaning.

Abstract: A three-dimensional structure of porous silicon considerably improves the anchorage of sensor-active material such as, for example, enzymes, antibodies, etc., on or in the substrate surface of chemical sensors, in particular silicon-based biosensors. This structure is produced by means of suitable etching which forms pore apertures adapted to the penetrability of the sensor-active material. The pore walls advantageously receive a non-conductive boundary layer which consists of oxides of Si and/or Al or Ta or silicon nitride and are preferably 1-100 nm thick. The porous layer is advantageously between 10 nm and 100 .mu.m thick and the pores are preferably in the form of branched ducts whose average diameter is 1 nm-10 .mu.m and in particular 10-1000 nm. The sensor-active material can optionally be distributed in a glass, solid, plastics or polymer membrane.