Graphene-gold nanoparticle composite-based electrochemical biosensor for human papilomavirus detection

A novel electrochemical biosensor was developed for ultrasensitive detection of DNA HPV using graphene-gold nanoparticle composites combined with a self-assembled DNA nanostructure amplification strategy. The biosensor construction involved a two-step synthesis of G-AuNP composites, characterized by UV–visible spectroscopy showing characteristic absorption peaks at 230 nm and 525 nm. The biosensor employed strategically designed auxiliary probes (AP1 and AP2) that enabled extended DNA nanostructure formation through programmed self-assembly, significantly enhancing detection sensitivity. Under optimized conditions, including 0.5 μM auxiliary probe concentration and 37°C hybridization temperature, the biosensor showed exceptional performance with a detection limit of 0.31 fM and reproducibility of 3.8 % RSD. The system demonstrated robust stability, maintaining 95.2 % of initial response after 14 days at 4°C. Clinical validation using cervical specimens showed excellent correlation with qPCR (R 2 = 0.997) and recovery rates between 95.8 % and 103.2 %. The biosensor's total analysis time of 65 minutes represented a significant improvement over conventional methods, while maintaining high selectivity against base mismatches and common interferents, making it suitable for rapid point-of-care diagnostics.