ИСТИНА

Synthetic receptors are promising alternatives to biorecognition elements as sensing materials. They possess some important advantages such as low cost, high operational and storage stability. For example, boronic acids selectively binding to 1,2- or 1,3-diols are alternative to lectines that possess high affinity to saccharides. Since the latter is one of major components of cell wall or cell membrane, "synthetic lectins" are able to solve some important medical or biotechnological objectives including air and product purity. However, existing methods of microorganism detection usually consist of additional pretreatment steps or require expensive equipment and reagents. Here we demonstrate reagentless sensor based on boronate-substituted polyaniline that generates electrochemical signal in the course of specific interactions with 1,2- or 1,3-diol moiety. Developed system is applicable for microorganism's detection in water and aerosol. The reported sensor allows discrimination of specific affinity interactions from non-specific binding. Underlying mechanism consists in self-doping phenomenon originating upon formation of negatively charged complex between boronate substituent of boronate-substituted polyaniline and diol fragments of saccharides and hydroxyacids. Sensor applicability to microorganisms' detection was proved on the base of impedimetric detection of Penicillium chrysogenum. We have chosen interdigitated microelectrode arrays (IDMEAs) that are among the most sensitive electrode structures used for this aim. Impedance spectra of boronate-substituted polyaniline-modified IDMEAs were recorded in liquid and aerosol. Impedance data in Nyquist plots demonstrate decrease of film resistance (discovered from the diameter of high-frequency semicircle, starting from the bottom left part) as a function of mold concentration. As seen, polymer film conductivity increases together with mold concentration. Microsensors are applicable for express analysis of air since they take less than 20 minutes to perform the measurements. Financial support through Russian Science Foundation grant #16-13-00010 is greatly acknowledged