Electrochemical diode biosensor for glucose detection and method for producing the same

Abstract

The subject of the application is a flexible polymer-carbon electrochemical biosensor with diode-type current-voltage characteristics (diode biosensor), used to detect glucose in aqueous solutions, and a method for its preparation, consisting in first preparing a substrate (1) made of polydimethylsiloxane constituting a template in which a set of two empty channels corresponding in shape to the polymer-carbon electrodes (2) which will be made in them, odd-fingered, at least three-fingered, is made, wherein: the channels for the polymer-carbon electrodes are arranged so that they interlock with each other, i.e. their fingers are arranged alternately, but with the distance between them maintained, the distance between the channels for the polymer-carbon electrodes is in the range from 10 to 600 µm, and the thickness of the channels for the electrodes does not exceed three times the value of the distance between them,then the channels are filled with a previously prepared liquid mixture constituting a dispersion of multi-walled carbon nanotubes in a polydimethylsiloxane-based matrix, in the nanotube to matrix proportions ranging from 0.5% to 25% by weight, and then - before cross-linking the polydimethylsiloxane - multi-walled carbon nanotubes composite - a wire (3) for transporting an electric charge, made of highly conductive carbon fibers impregnated with polydimethylsiloxane, i.e. covered with an insulating layer of polydimethylsiloxane with a thickness of 2 to 60 µm, is inserted into each of the channels, then the biosensor thus obtained is subjected to a thermal cross-linking process at a temperature of 60°C to 90°C, for a time of 1 to 8 hours,