Bimetallic core-shell nano-architecture of Au@Pt as an effective electrochemical mediator for ultrasensitive detection of Listeria monocytogenes in cerebrospinal fluid

Bacterial infections related to Listeria monocytogenes can lead to serious pathological conditions such as meningitis and meningoencephalitis in humans. Therefore, the detection of Listeria particles and byproducts is a very important issue in clinical settings. Nanostructures have been broadly utilized in different areas because of their unique physicochemical properties. Specifically, bimetallic nanostructures have been employed in the development of smart biosensor types. In the study, a simple and efficient platform utilizing bimetallic nanostructures was developed to create a diagnostic system for Listeria monocytogenes. The Au@Pt core-shell structure was synthesized and electrodeposited the glassy carbon electrode (GCE). A 24-mer thiolated single-strand probe, targeting the hly gene, was immobilized on the Au@Pt modified GCE to hybridize with the target sequence. Then, the electrochemical measurement with square wave voltammetry (SWV) technique was done to ensure the hybridization reaction. The biosensor's efficiency was validated using standard addition in real cerebrospinal fluid (CSF) samples, to assess biosensor specificity in the detection of bacterial genomics in biofluids. The obtained results indicate that the designed biosensor was able to detect the target genomic sequences. This platform was capable of detecting targets in 5 to 60 attomolar and was proved as a practical detection limit. It is suggested that the designed platform with high sensitivity and specificity for the detection of target gene sequences in biofluids.