Fabrication of a Silk-Glycerol-Based Flexible Electrode Decorated with WO3 Nanorods for Ultrasensitive Electrochemical Detection of Bacteria.

This paper reports the preparation and characterization of a silk-glycerol composite-based, biocompatible, optically transparent, and flexible substrate. Blending glycerol with silk not only eliminates the brittleness of pure silk films but also enhances flexibility and long-term mechanical stability. Its applicability in the electrochemical detection of Escherichia coli (E. coli) bacteria on a screen-printed electrode system is a testament to the robustness of the substrate. To improve the sensitivity and selectivity of E. coli detection, the working electrode is modified with amine-functionalized WO3 nanorods. The developed flexible biosensor platform selectively detects the targeted E. coli bacteria sample, even in mixed bacterial cultures and fungal strains, with an ultralow detection limit of 0.15 CFU/mL, and at the same time, it has a wide detection range starting from 0.15 to 1.5 × 104 CFU/mL. The repeatability, stability, and specificity studies in real samples affirmatively indicate its potential for usage in clinical applications.