A Novel SERS Substrate Containing Silver Nanoparticle-Deposited Photoresist Microcone Array for Sensitive Biosensing

In this study, we developed a novel surface-enhanced Raman scattering (SERS) substrate formed by depositing silver nanoparticles (AgNPs) on a silver thin film-coated photoresist (PR) microcone array. The semiconductor photolithographic process was adopted for fabricating the PR microcone array. The hotspot enhancement effect of the SERS substrates was optimized by adjusting the concentration of the trisodium citrate, which was used as a reducing agent and a stabilizing agent for the synthesis of AgNPs. Experimental results showed that the proposed SERS substrate could detect the indicating peaks of Rhodamine 6G (R6G) at a relatively low concentration of 10 -12 M. A standard detection curve for HbA1c detection with a linear detection range of 5000-20000 ng/mL with a good linearity of 0.994 and a limit of detection (LOD) of 850.2 ng/mL was further established by adding HbA1c agent to artificial blood to simulate a real environmental condition. Recovery rate detection experiments confirmed the reproducibility of the established standard detection curve.