Spoof-Surface Plasmon Polaritons and Surface-Enhanced Raman Spectroscopy Dual-Mode Detection of Multiple Biomarkers in Sweat

Surface-enhanced Raman spectroscopy (SERS) and spoof surface plasmon polaritons (spoof-SPPs) are two electromagnetic detection techniques that have received significant attention in recent years. In this work, a novel spoof-SPPs and SERS dual-mode detection of multiple biomarkers in sweat is introduced, which is based on an Archimedean spiral Cu patch integrated with a Ag nanocoral surface. As a spoof-SPPs sensor, the reflection spectrum of the Archimedean spiral Cu patch exhibits high sensitivity to target biomarkers, which also reveals significant shortcomings in the detection of multiple biomarkers with various proportions. With the help of Ag nanocoral surface on Cu patch, SERS spectrum of multiple biomarkers is also obtained on the same patch, which provides supplementary information about the proportions based on the intensities of their different characteristic Raman peaks. With the total amount of multiple biomarkers as the same, our data demonstrate that the variation of volume ratios (7:3, 5:5, and 3:7) between creatinine and urea in sweat at 100 nM could be accurately identified by spoof-SPPs and SERS spectra. Therefore, our novel spoof-SPPs and SERS dual-mode detection overcomes the deficiency of spoof-SPPs sensing on multiple targets and SERS sensing on quantitative analysis, which exhibits huge application prospective in accurate and reliable sensing on complex biochemical systems.