A dynamically optical and highly stable pNIPAM @ Au NRs nanohybrid substrate for sensitive SERS detection of malachite green in fish fillet.

A universal surface-enhanced Raman scattering (SERS) substrate with tuneable plasmonic behaviour and long-term stability was synthesized and characterized, and the substrate was applied in the sensitive detection of fungicide malachite green (MG) in fish fillets. Temperature-responsive poly (N-isopropyl acrylamide) (pNIPAM) template and anisotropic Au nanorods (NRs) were synthesized to prepare pNIPAM @ Au NRs nano-hybrids with dynamically optical and SERS properties and high stability. Results showed that excitation wavelength-dependent SERS efficiency could be tailored by temperature-induced swelling and collapse of the nano-hybrids, thus anticipated optical and SERS properties of the composites could be obtained. Furthermore, the SERS performance, uniformity, long-term stability analysis, and MG in fish evaluation showed that the detection of MG in fish tissues was realized with a limit of detection of 1.58 × 10-9 M (0.73 ng/g), and the pNIPAM @ Au NRs composites could serve as effective SERS substrates allowing trace level detection of contaminants for the food industry.