Microbial Sensor for Determination of Amoxicillin Activity

Abstract

A sensor based on the electrodynamic microwave resonator has been developed to determine the antibacterial activity of antibiotics using amoxicillin as an example. Microbial cells immobilized on the polystyrene film surface were used as a sensitive element of the sensor. The optimal conditions for the immobilization of Escherichia coli Xl-1 microbial cells on the surface of a thin polystyrene film modified in high-frequency argon discharge plasma and deposited on a lithium niobate plate were determined. The effect of amoxicillin on immobilized microbial cells was studied using the developed sensor. It has been established that the increase in con- centration of amoxicillin from 5 to 50 μg/ml leads to a significant change in the reflection coefficient S11 at the resonance frequency from the lithium niobate plate in the range of -12.6 dB — -15.1 dB. It has been shown that the developed sensor allows determining the antibacterial activity of drugs in the studied concentration range with an analysis time of 15 min.