Closing the Loop: Sustainable and Cost-Effective Glucose Biosensors Through a Circular and Digital Design

Electrochemical biosensors are becoming increasingly prevalent across medical, food, and bioprocessing industries for monitoring complex biological processes. However, their sensitivity to contamination and exposure to potentially hazardous biological species often necessitates single-use disposal, contributing to the release of high-value, high-demand, and environmentally damaging materials into the environment. This study investigates the feasibility of a closed-loop recycling process for single-use glucose biosensors, with a focus on the recovery and reuse of noble metals silver and gold. Guided by ecodesign principles and using low-impact materials, we developed a silver screen ink, gold syringe ink, and a poly(lactic acid) (PLA) substrate. Sensors were fabricated by additive manufacturing and screen printing—enabling the scalability afforded by screen printing to produce the high-coverage silver layer while also minimising gold ink waste using additive manufacturing. A low-energy recovery method that exploited selective solvent compatibility was developed to reclaim silver and gold. Second-generation devices were then fabricated, demonstrating performance comparable to commercial equivalents while achieving an 80% reduction in material usage, cost, and environmental impact across 16 categories using a life cycle assessment (LCA).