Highly sensitive and repeatable DNA-SERS detection system using silver nanowires-glass fiber filter substrate

This paper describes a new simple DNA detection method based on surface-enhanced Raman scattering (SERS) technology using a silver nanowire stacked-glass fiber filter substrate. In this system, DNA-intercalating dye (EVAGreen) and reference dye (ROX) are used together to improve the repeatability and reliability of the SERS signals. We found that the SERS signal of EVAGreen was reduced by intercalation into DNA amplicons of a polymerase chain reaction on the silver nanowire stacked-glass fiber filter substrate, whereas that of ROX stayed constant. The DNA amplicons could be quantified by correcting the EVAGreen-specific SERS signal intensity with the ROX-specific SERS signal intensity. Multivariate analysis by partial least square methods was also successfully performed. And we further applied it to loop-mediated isothermal amplification with potential use for on-site diagnostics. The sensitivities of the DNA-SERS detection showed about 100 times higher than those of conventional fluorescence-based detection methods. The DNA-SERS detection method can be applied to various isothermal amplification methods, which is expected to realize on-site molecular diagnostics with high sensitivity, repeatability, simplicity, affordability, and convenience.