Design and Fabrication of Honeycomb-Structured Surface Enhanced Raman Scattering (SERS) Substrate for DNA Detection

The sensitivity of conventional flat SERS substrates for DNA detection by the “sandwich” strategy is limited due to the insufficient conformal gaps between metal surfaces. This paper introduces the design and fabrication of a honeycomb-structured highly sensitive SERS substrate created by silica-inverse opal photonic crystals. Gold nanoparticles (AuNPs) are aligned within the gold-coated honeycomb cavities with good conformity, providing sufficient hot spots for surface-enhanced Raman scattering (SERS) signaling, thereby achieving high sensing sensitivity. The design of the SERS system is symmetrically investigated through numerical simulations, and the fabrication of honeycomb cavities is optimized by tuning the size of sacrificial polystyrene nanospheres and the content of ethyl silicate. Detection of target DNA sequences of Escherichia coli (E. coli) as low as 0.1 nM is achieved by using the SERS substrate, indicating its potential applications in disease diagnosis and environmental monitoring in the future.