Colorimetric Biosensor For Fast Detection Of Staphylococcus Aureus Based On Catalytic Gold Nanoparticles

Abstract

Staphylococcus aureus (S. aureus) is the most prevalent cause of hospitalacquired infections and is regarded as one of the leading bacteria contributing to foodborne diseases. Numerous techniques have been developed for S. aureus detection and quantification. Nevertheless, the majority of these techniques often require laborious sample preparation processes and take a long time. Thus, the development of a quick, easy, and sensitive detection technique is very desirable. A colorimetric biosensor based on catalytic gold nanoparticles was created to overcome these restrictions. In this study, a colorimetric biosensor for fast detection of S. aureus based on catalytic gold nanoparticles was developed, which is based on an RNA of bacteria, single-stranded specific cleavage activity of Mung bean nuclease enzyme, and peroxidase-like activity of AuNPs on TMB. Without the use of an analytical tool, it is possible to quantify the response signals with the naked eye and determine the outcomes. The presence of target RNA is implied by the fact that the DNA-RNA hybrid, once created, resists the cleavage of the Mung bean nuclease enzyme and maintains its red color in the solution. When an RNA target is not present, this prevents DNA-RNA hybridization from occurring, singlestranded DNA probes are vulnerable to enzymatic breakage by Mung bean nuclease, which leaves the unprotected nanoparticles. Unprotected AuNPs may oxidize 3,3,5,5- tetramethylbenzidine (TMB) and cause it to become blue in aqueous solutions by catalyzing the reaction with H2O2. In short, the nanosensor simply changed color, when the RNA non-target was present in the samples. The biosensor findings were visually inspected and subjected to UV-Vis spectroscopic analysis. The specificity of the method is demonstrated by the absence of false positive results. The naked eye detection limit of this method is 107 CFU/ml. The total analysis time for this method is approximately two and a half hours after RNA extraction. This sensing tool requires a minute to obtain the results. This nanosensor platform, when compared to conventional techniques, could offer a fresh approach and satisfy the pressing need to improve pathogenic bacterial detection, which includes making it easy, affordable, rapid, and suitable for in situ detection.