HIGHLY SENSITIVE LABEL-FREE ELECTROCHEMICAL DETECTION OF HEAT SHOCK PROTEIN WITH LOW-COST SCREEN-PRINTED ELECTRODES

Abstract

Heat shock proteins (HSPs) are produced when organisms are exposed to various environmental stress conditions such as extreme temperatures, light, and toxins. It is a known fact that in bacteria which have the HSP gene (hsp), antibiotics can trigger the expression of these proteins. However, the response of HSP genes to antibiotics has not been fully clarified in the literature, with studies still ongoing. In this work, a novel method of detecting heat shock protein 65 (HSP65) was investigated using electrochemical impedance spectroscopy (EIS) due to its sensitivity and selectivity. To do so, a specific HSP65 probe and target were designed and their hybridization behaviour was studied using low-cost screen-printed electrodes (SPEs). Cyclic voltammetry was performed to analyse surface characteristics of the SPEs and the performance of the electrodes was tested using EIS, by measuring changes in the charge transfer resistance upon probe binding and target hybridization. Increases in charge transfer resistance were measured and observed to be in-line with literature. Based on these results, the designed HSP65 probe was confirmed to bind the target sequence and proved that the EIS can be effectively used to detect HSP65 label-free. Results presented here could lead to development of antibiotic susceptibility assays based on hsp genes in future and provide a quicker test for the detection of many slow-growing bacteria.