Conventional biosensors frequently rely on biological enzymes such as glucose oxidase and peroxidase to catalyse specific biochemical reactions. While effective, these enzymes present several critical limitations, including limited operational stability, high production and storage costs, and sensitivity to environmental conditions. These drawbacks significantly hinder their practical application in long-term diagnostics, portable sensing devices, and resource-limited settings.

This project proposes the development of enzyme-free biosensors using silver nanoparticles (AgNPs) as catalytic substitutes. AgNPs exhibit unique and advantageous physicochemical properties, including a large surface area, excellent electrical conductivity, and intrinsic peroxidase-like activity. These features make them ideal nanozyme candidates for next-generation biosensors that are both efficient and stable under diverse conditions.

This study involves the synthesis and characterisation of AgNPs via chemical and environmentally friendly (green) methods, followed by their integration into both electrochemical and colorimetric biosensing platforms. The biosensors are tested for their ability to detect clinically and industrially relevant biomolecules, particularly glucose and hydrogen peroxide.

Key performance metrics such as the biosensors' sensitivity, detection limit, response time, selectivity, and long-term operational stability are systematically evaluated and compared with those of their conventional enzyme-based counterparts. The ultimate goal is to develop a cost-effective, reusable, and robust biosensor suitable for applications in medical diagnostics, food safety analysis, and environmental monitoring.

This work contributes to the growing field of nanozyme technology by offering an innovative, enzyme-free solution to overcome the limitations of traditional biosensors, paving the way for the development of more durable and accessible sensing platforms.