One-Pot Synthesis of a Three-Dimensional Au-Decorated Cellulose Nanocomposite as a Surface-Enhanced Raman Scattering Sensor for Selective Detection and in Situ Monitoring

Abstract

Metal nanoparticles (NPs) have been commonly introduced onto flexible platforms for improving their exploitation. However, such an introducing process of NPs is hard to achieve, and additional dispersants and high-energy consumption are largely required in existing studies. In this study, a one-pot method was developed to synthesize Au NPs in a cellulose dope. The dissolved cellulose chains acted as a green reductant as well as a stabilizer. As the polysaccharide dope coagulated, a three-dimensional (3D) regenerated cellulose nanocomposite decorated with 0.29–1.07 wt % Au NPs was successfully synthesized. As supported by the “hot spot” effect among the Au NPs embedded in the 3D structure, the nanocomposite could act as a sensitive surface-enhanced Raman scattering (SERS) substrate. Accordingly, this study achieved an enhancement factor of 2.8 × 107 and a limit of detection of 10–9 M when R6G was employed as a probe molecule. Moreover, as impacted by the porous structure of the SERS substrate, 2.5 mg/kg melamine in milk could be directly detected. Furthermore, organic contaminants were catalytically reduced, and the process of catalytic reduction underwent in situ SERS monitoring with excellent sensitivity.