ИСТИНА

The growing concerns about environmental safety have promoted an intensive development of rapid, simple and sensitive methods for the detection of microorganisms to ensure occupational and public health. Conventional microbiological methods are laborious, time-consuming or expensive, and usually unsuitable for on-site analysis. To overcome most of these drawbacks it is possible to use synthetic receptors instead of biorecognition elements. The developed sensing material – poly(3-aminophenylboronic acid) or poly(3-APBA) – is able to selectively bind compounds possessing 1,2- or 1,3-diol moiety which are common part of sugars and hydroxyacids. In previous work we reported on the novel reagentless and label-free detection principle of the above-mentioned small molecules allowing discrimination of specific binding over non-specific interactions [1]. Specific and unspecific signals of majority of impedimetric and conductometric (bio)sensors are directed in the same way of decrease in conductivity making doubtful their real applications. In contrast, the response of the reported sensing material poly(3-APBA) results in resistance decrease, which is directed oppositely to the background. However, a diversity of potential analytes for the polymer is not limited to sugars and hydroxyacids. It seems that poly(3-APBA) is able to bind to fungal cell wall surface, which consists mainly of β-1,3-glycan. The glycan contains repeating units of glucose with 1,3-cis-diol fragments which are known to selectively bind to phenylboronic acid. Apparently, boronate groups of poly(3-APBA) binds to diols within cell wall which causes doping of conducting polymer in solution [2]. In this work, we elaborated microsensor for direct, rapid, reagentless and label-free detection of Penicillium chrysogenum in air [3]. It was first shown that the presence of the microorganism in air led to conductivity increase of electropolymerized 3-APBA (see the figure). We believe that spores of Penicillium chrysogenum with sizes of 2–4 μm undergo sorption on the surface of poly(3- APBA) due to specific interaction of the cell wall functional groups with boronic acid moiety which cause increase in conductivity of the polymer. Effect of poly(3-APBA) conductivity increase as a result of polymer self-doping in the presence of the fungi was confirmed by Raman spectroscopy. Detection of fungi with microsensor requires less than 20 minutes which is approximately 100 times faster than agar plate cultivation. Furthermore, microsensor is applicable to monitor hygienic standard of fungal content in air. Reagentless operation in air and compact size of microsensors opens the possibility to create embedded systems of air control in manufacturing processes and even in everyday life. The reported application of reagentless sensing principle is upcoming approach to detect complex analytical objects such as microorganisms in a simple manner opening new prospects for health care. References: [1] Andreyev E.A., Komkova M.A., Nikitina V.N., Zaryanov N.V., Voronin O.G., Karyakina E.E., Yatsimirsky A.K., Karyakin A.A. Analytical Chemistry 2014, 86, 11690–11695 [2] Komkova M.A., Andreyev E.A., Nikitina V.N., Krupenin V.A., Presnov D.E., Karyakina E.E., Yatsimirsky A.K., Karyakin A.A., Electroanalysis 2015, 27, 2055–2062 [3] Andreev E.A., Komkova M.A., Shavokshina V.A., Presnov D.E., Krupenin V.A., Karyakin A.A. Electroanalysis, 2018, 30, 602-606