Substrate addition and matrix optimization increased sensitivity and selectivity of the PLGA sensor, resulting in a stronger detection signal toward bacterial contaminations

摘要

The aim of this work was to contribute to the development of a simple and cheap biomimetic sensor, providing a higher sensitivity and selectivity toward microbiological contaminations in a test product. The biosensor is composed of two different layers: a) mirror layer and b) biomimetic poly (lactic-coglycolic acid) (PLGA) layer that can be degraded by microbial lypolitic enzymes. Changes in the thickness of the polymer layer are resulting in a colour change of the biosensor's surface. We have investigated the biology and propagation of several bacteria (Pseudomonas, Enterobacter, Proteus and Salmonella) and their metabolitic pathways. Not all bacteria produced an equal amount of lipolytic enzymes at the same stage of their reproduction, and there was no connection with a total bacterial counts. Under addition of certain substrates in the matrix of the biosensor, it was possible to stimulate the bacteria for better enzyme production, resulting higher sensitivity of the PLGA biosensor.