Engineering polymeric substrates: how sustainable and active materials enhance electrochemical point-of-need devices

: The widespread use of petroleum-based polymer substrates in point-of-need (PON) electrochemical sensors and biosensors raises significant environmental sustainability concerns, particularly in the context of large-scale deployment and single-use devices. Beyond environmental impact, substrate selection critically influences analytical performance, sampling efficiency, and long-term operational stability. In this context, sustainable polymeric materials, including natural polymers ( e.g. , cellulose, silk fibroin, and chitosan), and biodegradable synthetic polymers ( e.g. , polylactic acid, polycaprolactone, and polyethylene glycol), have emerged as promising alternatives to conventional substrates. These materials combine biocompatibility, mechanical robustness, flexibility, and tunable surface chemistry, while enabling substrate-driven functionalities such as integrated sample handling, enhanced mass transport, and improved bio-interface stability in complex biological fluids. However, despite these advantages, challenges related to manufacturing reproducibility, scalability, and standardization remain critical barriers to field-translation. The review examines how sustainable polymer substrates are advancing electrochemical PON devices beyond the state of the art, analyzing performance benefits and drawbacks and highlighting future directions for the development of environmentally responsible and analytically robust diagnostic platforms.