ИСТИНА

Conventional methods of microorganism detection have limited application for medical, urban and industrial and environmental purposes. They often include time-consuming steps with special sampling and pretreatment. Investigation of reagentless, express, reliable, sensitive and on-site method of detection is therefore of great importance. Phenylboronic acids are known to form stable esters with cell wall polyol components and were successively applied for direct sensing of microorganisms. However, developed electrochemical systems often lack practical importance due to several drawbacks such as generally low stability, high cost, and restricted mass production. Some systems are able to overcome above listed drawbacks, however, the major one remains – specific and non-specific signals (background) are directed in resistance increase. Boronate-substitued polyaniline is a promising material for microorganism detection. On the one hand, boronate residue does not require pretreatment and reagents prior to sensing making the whole procedure reagentless and express. On the other hand, polyaniline chain serves as advanced transducer possessing high conductivity and chemical stability. We present novel reagentless principle of microorganism detection which allows discriminating specific and non-specific interactions. This feature is provided by boronate-substituted polyaniline conductivity change. Specific binding results in conductivity increase in the course self-doping phenomenon which coincides with formation of negatively charged substituent in polymer chain [1]. Non-specific interactions on the contrary lead to decrease of conductivity. We tested investigated system in detection of microorganism Penicillium chrysogenum. Interdigitated electrode arrays were modified with investigated polymer. Interdigitated structures were found to be among the most sensitive electrode structures used for sensing application [2]. We observed continuous increase of conductivity with increasing concentration of cells in liquid media. Limit of detection is approximately 1000 CFU/ml. The authors acknowledge the financial support from joint MSU-LGE lab. References: 1. E.A. Andreyev, M.A. Komkova, V. N. Nikitina, N.V. Zaryanov, O.G. Voronin, E.E. Karyakina, A.K. Yatsimirsky, A.A. Karyakin, Analytical Chemistry 2014, 86(23), 11690-11695 2. M. Varshney, Y. B. Li, Biosensors & Bioelectronics 2009, 24, 2951-2960