Biomimetic Nano-Pine-Pollen Structure-Based Surface-Enhanced Raman Spectroscopy Sensing Platform for the Hypersensitive Detection of Toxicants: Cadmium and Amyloid

In the field of surface-enhanced Raman scattering (SERS) sensors, biomimetic micro/nanostructures have been fabricated to improve sensing performance. In this study, we developed a biomimetic nano-pine-pollen nanostructure (NPP-NS)-based SERS sensing platform that enables the hypersensitive detection of toxicants, such as toxic heavy metal ions and amyloid-β oligomers. The secondary gold nanostructures of NPP-NS were formed on the silver nanostructure through a galvanic replacement reaction, which increased the surface area and created electromagnetic hotspots, enhancing the SERS responses. Specifically, NPP-NS exhibited the most effective SERS performance with an analytical enhancement factor of 3.86 × 1013. Through experimental analysis and computational simulations, NPP-NS was optimized as a SERS sensing platform. Additionally, the sensing performance of NPP-NS was consistently highly stable for several days without structural oxidative degradation, despite being in the harsh oxidation state, owing to the secondary gold nanostructure. Moreover, we utilized the NPP-NS SERS sensor for biosensor applications capable of detecting toxicants, such as cadmium ions and amyloid-β oligomers with a detection limit of up to 10 pM, in drinking water and human plasma samples, respectively. As a pilot study, the biomimetic NPP-NS could be used as a hypersensitive SERS sensing platform to detect other biological and chemical toxicants.