Highly reproducible nanofilms assembled from quaternary ammonium polymer-functionalized graphene oxide and gold nanoparticles for sensitive SERS detection of antibiotics

Surface-enhanced Raman scattering (SERS) stands out as a valuable tool for the rapid and precise detection of trace antibiotics. However, preparing SERS substrates with high sensitivity, homogeneity, and good stability remains a great challenge. In this study, we chemically functionalized graphene oxide (GO) with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) through surface-initiated atom transfer radical polymerization (SI-ATRP) technique. Then, GO- g - q PDMAEMA was obtained by quaternization (the quaternized PDMAEMA is denoted as q PDMAEMA). Using a water/oil interface self-assembly approach, we fabricated GO- g - q PDMAEMA/AuNPs nanofilms by interfacial assembly between GO- g - q PDMAEMA in chloroform and AuNPs in water. The nanofilms exhibited remarkable SERS characteristics, including exceptional sensitivity, good homogeneity, reproducibility, and stability. Additionally, two commonly used antibiotics, i.e., sulfamonomethoxine (SMM) and enrofloxacin (ENR) were rapidly and sensitively detected using the prepared GO- g - q PDMAEMA/AuNPs nanofilms as a SERS platform. The developed GO- g - q PDMAEMA/AuNPs nanofilms hold significant promise for food safety monitoring and environmental analysis.