Polyaniline-graphene oxide (PANI/GO)-grafted paper-based nanosensor for the detection of Helicobacterpylori

A polyaniline-graphene oxide (PANI-GO) nanocomposite-grafted DNA biosensor for detecting Helicobacter pylori-specific toxins, oncoprotein cytotoxin-associated gene A (CagA), has been reported. The nanocomposite was fabricated on Screen printed paper electrode (SPPE) and modified with a 5'NH₂-labelled single-stranded DNA (ssDNA) probe specific to the CagA gene via an EDC/NHS cross-linker. Under optimized electrochemical experimental conditions, CV and DPV were used to analyse the performance of the developed biosensor. A linear dynamic range for H. pylori ssDNA was established between 0.00001 ng/microl and 0.1 ng/microl, with correlation coefficients of R² = 0.9813 for the CV and R² = 0.9343 for the DPV. The sensitivities of the developed sensor in the CV studies were 50.261 microA microL/ng∙mm² and 66.5 microA microL/ng∙mm² in the DPV studies. CV demonstrated an LOD of 0.0026 ng/microL, whereas the LOD of the DPV studies was 0.001 ng/microL. The developed sensor was validated using different concentrations of H. pylori ssDNA spiked in human stool samples. The results highlight the potential of the developed biosensor to detect and quantify H. pylori genomic DNA in a sensitive and reliable manner to aid in clinical diagnostics and pathogen detection applications.