Nanomaterials applied in biosensor development

Nanomaterials have significantly advanced biosensor development by enabling highly efficient sensing interfaces with enhanced sensitivity, selectivity, signal amplification, and analytical performance. This narrative review provides a comprehensive overview of the main classes of nanomaterials used in biosensing, including metallic nanoparticles, carbon-based nanomaterials, quantum dots, and hybrid nanocomposites. This review focuses on the physicochemical mechanisms by which these materials improve biosensor performance, including increased electroactive surface area, accelerated electron transfer, electrocatalytic activity, optical signal enhancement, and stable biofunctionalization of recognition elements. This review discusses key immobilization strategies in relation to their effects on sensitivity, selectivity, reproducibility, and operational stability. Representative biosensor platforms are critically evaluated according to their detection mechanisms, analytical performance, advantages, limitations, and applications in clinical diagnostics, environmental monitoring, food safety, and pharmaceutical analysis. Hybrid nanomaterials emerge as particularly promising because they combine complementary properties within a single sensing interface, enabling improved electron transfer, greater active surface area, enhanced bioreceptor immobilization, reduced overpotentials, and amplified analytical signals. Despite substantial progress, important challenges remain regarding reproducibility, long-term stability, biocompatibility, selectivity in complex matrices, standardized fabrication, large-scale manufacturing, and regulatory validation. Future research should therefore prioritize translating high-performance laboratory prototypes into robust, scalable analytical platforms validated on complex real samples. Integrating nanomaterials with screen-printed electrodes, paper-based devices, wearable sensors, microfluidics, smartphone-assisted platforms, and artificial intelligence is expected to drive the next generation of biosensing technologies. These advances may enable more accessible, portable, cost-effective, and reliable biosensors for point-of-care diagnostics, personalized healthcare, environmental monitoring, food safety, and pharmaceutical analysis. Graphical Abstract