Surface stress-induced membrane biosensor based on double-layer stable gold nanostructures for E. coli detection

The surface stress-based biosensor has been applied in fast and sensitive identification of Escherichia coli (E. coli)with significance for public health, food, and water safety. However, the stable sensitive element of flexible biosensor based on surface stress is still crucial and challengeable. Here, the authors reported surface stress-induced biosensors based on double-layer stable gold nanostructures (D-AuNS-SSMB) for E. coli O157:H7 detection. Bacterial detection demonstrates the high stability of the biosensor. The resistance change of biosensor is linear to the logarithmic value of the E. coli O157:H7 concentrations ranging from 10³ to 10⁷ CFU/mL with a limit of detection (LOD) of 43 CFU/mL. The captured signals of D-AuNS-SSMB comes from surface stress generated by antigen-antibody binding. In addition, the biosensor exhibits good stability, reproducibility and specificity in detection of E. coli O157:H7 as well. This study provides a new preparation method of stable sensitive element for the E. coli detection.