A Miniaturised Electrochemical Platform for Rapid Detection of Insulin.

The development of biosensors has revolutionized medical diagnostics and healthcare monitoring. Integration of nanomaterials, such as gold nano-islands (Au NIs), enhances the performance of electrochemical biosensors by increasing the active sites for biomolecular reception and the transduction of binding events into electrical signals. Insulin detection is critically required for automated type 1 diabetes management. Here, we report an aptamer-based electrochemical biosensor design for the rapid, sensitive, and selective detection of insulin. Au NIs are deposited on screen-printed carbon electrodes (SPCEs) using a flame-based aerosol approach. The Au NIs are functionalised with an insulin-specific DNA aptamer, and the residual sensor surface is passivated with 6-mercapto-1-hexanol and bovine serum albumin. Our biosensor exhibits a linear response to insulin concentrations from 1 to 100 µM and demonstrates excellent selectivity for insulin as tested against glycine, glucose, ampicillin, glycated and non-glycated human serum albumin. Our biosensor's performance is validated in spiked mice serum exhibiting high recovery rates, thereby indicating its sensitivity and accuracy in real clinical scenarios. The selectivity of this biosensor is also assessed in mice serum to further emphasise on its clinical potential, demonstrating the potential for point-of-care diagnostics, wearable health monitoring devices, and personalised medicine for diabetes management.