Abstract
The rapid progress in biosensing technologies has intensified the demand for platforms that exhibit high sensitivity, selectivity, portability, cost-effectiveness and robustness in complex real-world environments. This thesis address the challenges through the development of biosensors based on organic-inorganic hybrid (OIH) nanomaterials, specifically engineered to bridge the gap between high-precision laboratory electrochemical techniques and point-of-care diagnostic applications. The research utilizes the electrocatalytic activity of nanostructured metal oxides, noble metals and inorganic nanomaterials, integrated within conductive and chemically stable organic matrices. This hybrid approach effectively avoids the reliance on enzymatic components, while preserving high analytical reliability and operational robustness. The study is structured around three major contributions. First, the synthesis and comprehensive characterization of OIH nanomaterials are reported, with particular focus on controlling morphology, surface chemistry and electronic structure to maximize catalytic performance. Second, these engineered materials are deployed in multiple sensor architectures, including disposable paper-based electrodes and extended-gate field-effect transistors (EGFETs), demonstrating their compatibility with scalable and adaptable fabrication strategies. Third, the functional validation of the sensors is carried out through the detection of clinically relevant analytes such as glucose, dopamine, epinephrine, iodide and cysteine, where they achieve high sensitivity, reproducibility, and long-term stability under physiologically relevant conditions. Beyond material and device optimization, the thesis extends into system-level integration by coupling the sensors with microcontroller-based platforms and Internet of Things (IoT) infrastructures, enabling wireless, real-time acquisition, processing, and transmission of electrochemical signals. This convergence of hybrid nanomaterials, electroanalytical sensing, and digital communication technologies show the potential of the developed biosensors for next-generation telemedicine and personalized. Collectively, the findings provide a generalizable framework for enzyme-free biosensing and outline a roadmap for converting laboratory-scale innovations into practical, scalable technologies capable of addressing pressing global challenges in health and environmental sustainability.