Biosensors based on conductometric detection

Abstract

The present paper is a self-review on the development of about 20 conductometric biosensors based on planar electrodes and containing different biological material (enzymes, cells, antibodies), bio-mimics or synthetic membranes, including Imprinting polymers, as a sensitive element. Highly specific, sensitive, simple, fast and cheap determination of different analytes makes them promising for needs of medicine, biotechnology, environmental control, agriculture and food industry. Non-specific interference of back­ ground ions may be overcome by the differential mode of measurement, the usage of rather concentrated sample buffer and additional negatively or positively charged membranes, which decrease buffer capacity influence and extend a dynamic range of sensors response. For development of easy-to-use small conductometric immunosensors several approaches seem to be promising: i) the usage of polyaniline as electroconductive label for antibodies detection in competitive electroimmunoassay; ii) the elaboration of multilayer structures with phtalocyanine films; Hi) the usage of acrylic copolymeric membranes. The advantages and disadvantages of conductometric biosensors created are discussed. For future commer­ cialisation our effort are aimed to unite a thin-film technology with membranes deposition and to find the ways of membrane stabilisation, including bio-mimics creation, utilisation of bioaffinity polymeric membranes, imprinting polymers etc.