ИСТИНА

Microbial contamination of indoor air is important for occupational and public health. Among different microorganisms the microscopic fungi Penicillium, Aspergillus etc. are most common airborne genera. They can cause mycosis, mycogenic food or drug allergies, rhinosinusitis and bronchial asthma. Beside the harm to the human health there is also a negative influence of microorganisms on manufacturing processes of medicines, foods and microelectronics. Previously we reported on the novel reagentless and label-free detection principle allowing discrimination of specific binding over non-specific interactions [1]. Unlike majority of impedimetric and conductometric (bio)sensors, which specific and unspecific signals are directed in the same way (resistance increase), making doubtful their real applications, the response of the reported sensing material poly(3-aminophenylboronic acid) or poly(3-APBA) results in resistance decrease, which is directed oppositely to the background. The developed sensing material – poly(3-APBA) – is able to selectively bind compounds possessing 1,2- or 1,3-diol functions which are common part of sugars and hydroxyacids. However, a diversity of potential analytes for the polymer is not limited to above-mentioned small molecules. It seems that poly(3-APBA) is able to bind to fungal cell wall surface, which consists mainly of b-1,3-glycan. The glycan contains repeating units of glucose with 1,3-cis-diol functions 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 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. We believe that spores of Penicillium chrysogenum with sizes of 2–4 mm 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 not only to detect complex analytical objects such as microorganisms in a simple manner but also for elaboration of non-enzymatic selective sensors for key metabolites (possessing diol functions such as glucose or lactate etc.) that open 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. Anal. Chem. 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.