LAUSR

The reliable sensing of bacteria by surface-enhanced Raman scattering (SERS) technology necessitates a rational design of substrate with high sensitivity, stability and minimal invasion. Hence, a bimetallic Ta@Ag film with porous array is developed by magnetron sputtering technique, and the structure could be controlled by Ta dopant. Porous array connected by ligaments with compact granular nano-protrusion is a fascinating substrate for SERS sensing. It makes steady SERS signals even in harsh chemical environments, due to its high structural and chemical stability. The configuration of binary Ta@Ag has higher surface free energy than that of pure Ag, and the strong bactericidal activity of Ag is suppressed effectually. Using E. coli as a model pathogen, the Ta@Ag porous film could maintain the long-term survival rate of E. coli up to 95%, limit of SERS detection of E. coli down to 102 CFU/mL, which is measured by standard colony-counting method. In sum, this work provides a promising strategy to fabricate corrosion-resistant and biocompatible bimetallic Ta@Ag film with porous array, availing for the SERS sensing of microbial cell.