Photo-induced in-situ synthesized nanocellulose-based SERS substrate integrated with molecularly imprinted polymer for selective detection of pesticide residues

Surface-enhanced Raman scattering (SERS) is a highly sensitive technology to detect target analytes. Herein, we propose a novel nanocellulose-based SERS platform integrating SERS with molecular imprinting technology (MIP) for ultrasensitive and selective detection of pesticide residues. A uniform, dense, and surface-clean “hot spots” nanostructure was eco-friendly constructed based on cellulose nanofiber (CNF) films. The CNF film serves as a substrate for the photo-induced in-situ growth of silver nanoparticles without additional reducing agents and surfactants. By regulating pre-polymer viscosity (8.7 mPa·s at 2-hour pre-polymerization), a thin and uniform MIP layer was precisely coated on the “hot spots” via dip-coating, ensuring optimal balance between selectivity and SERS activity. The resulting SERS-MIP architecture increases the likelihood that target molecules penetrate MIP-covered “hot spots”, yielding high sensitivity, reproducibility, and specificity toward parathion-methyl. The SERS substrate exhibited excellent sensitivity, reproducibility and selectivity for parathion-methyl, with a limit of detection of 3.97 × 10 −11  g/L and relative standard deviation of 7.60%. Moreover, it demonstrated remarkable capability in detecting pesticide residues on irregular surfaces of real samples, using a wiping sampling method that fully leverages the flexibility of the CNF film. This approach successfully integrates MIP with SERS technology, offering a flexible SERS substrate for on-site food safety monitoring.