An electrochemical DNA biosensor based on gold nanoparticles/reduced graphene oxide nanocomposites for the detection of drug-resistant bacterial strain.

In recent years, gold nanoparticle-based biosensors have emerged as a rapid, specific, easy, and cost-effective alternative for detecting human, plant, and animal pathogens. Klebsiella pneumoniae (K. pneumoniae) is one of the most common drug-resistant pathogenic strains that cause nosocomial infections and outbreaks. Therefore, efforts to address the disease have focused on development of novel diagnostic technologies. The present study highlights the development of a sensitive electrochemical DNA biosensor for K. pneumoniae detection, fabricated on a glassy carbon electrode (GCE) modified with gold nanoparticles/reduced graphene oxide (AuNPs/rGO). Using greener methods to synthesize AuNPs promotes sustainability and enhances biocompatibility and environmental safety. By using an indicator-free approach, the current biosensor identifies K. pneumoniae infection and further minimizes the need for additional dyes to function as hybridization indicators. Square wave voltammetry (SWV) was used to characterize DNA immobilization and hybridization. The limit of detection (LOD) of the biosensor for the target K. pneumoniae DNA sequence was 0.16 pM with a detection range of 0.01-100 pM. The DNA biosensor facilitates rapid detection of target K. pneumoniae DNA, with 2-5 minutes of detection time. The DNA biosensor demonstrated high specificity in distinguishing complementary DNA sequences from interfering species. The results indicated that the AuNPs/rGO nanocomposite was a promising substrate for the development of high-throughput electrocatalysts for K. pneumoniae determination.