SERS Activity of Ag Nanoparticles Modified Ag–Cu Alloy Nanopillar Array Towards Creatinine Detection

Surface-enhanced Raman scattering (SERS) sensors are ideal for point-of-care testing (POCT) of disease markers; the key to practical applications lies in their quantitative detection capabilities and high sensitivity. In this study, We propose a simple method to develop a high-sensitivity composite SERS substrate using physical vapor deposition (PVD) technology. This SERS substrate, utilizing 4-aminothiophenol (4-ATP) as the detection molecule, demonstrated a high enhancement factor (~ 10⁶) and a low detection limit (10⁻¹⁰ M). The corrected linearity problem achieved good linear correlation (R² = 0.988) by using 4-ATP. In the trace detection process of creatinine, when creatinine is dissolved in goat serum solution diluted 1000 times, there is still a clear SERS signal at the characteristic peak when the concentration is only 10⁻⁴ g/l, further demonstrating the potential of SERS sensors in the detection of renal disease biomarkers.