DNA Origami-Assembled Bimetallic Gold–Silver Nanobipyramids: Enhanced Surface-Enhanced Raman Scattering for Thiram Pesticide Detection

Bimetallic nanostructures are a promising avenue for enhancing the capabilities of surface-enhanced Raman scattering (SERS), particularly those that incorporate a hybrid of gold and silver. Anisotropic hybrid plasmonic nanostructures with sharp edges hold great promise for tremendous electric field enhancement at specific locations, known as hotspots. In this study, nanoscale assembly of Ag-coated Au nanobipyramid (Au@Ag NBP) dimers with a controlled nanogap was achieved using an elegant deoxyribonucleic acid (DNA) origami technique. We have explored these Au@Ag NBPs-DNA origami assemblies for the SERS-based detection of thiram pesticide. The detection of thiram pesticides is significantly important due to their widespread use in agricultural practices and their potential environmental and health impacts. The monomer assemblies were able to detect thiram with 1 aM sensitivity, whereas the dimer assemblies showed SERS sensitivity of 0.5 aM with a limit of detection of 0.45 aM. Additionally, the designed SERS substrate was successfully employed to detect thiram on apple peel surfaces, further confirming its highly sophisticated sensing capability in real-world applications. Overall, our research underscores the potential of DNA origami-templated bimetallic nanobipyramids for detecting pesticides, contributing to the development of advanced sensing platforms for environmental monitoring and agricultural management, further enhancing our ability to detect and address pesticide-related risks.