Plasmonic Chiral Nanoprobes for SERS-based Enantioselective Sensing of Fructose in Complex Food Matrices

Given that enantiomers can exhibit distinct biological activities, accurately measuring their content is of significant research importance. d-fructose is a sweetener widely used in food manufacturing in many countries, whereas its enantiomer l-fructose is biologically inert, affects normal human metabolism, and also poses challenges to food authenticity verification. In this study, plasmonic chiral nanoprobes were developed for surface-enhanced Raman scattering (SERS)-based enantioselective sensing of fructose. Herein, cysteine served as an inducer to synthesize gold nanoparticles with intricate surface structures. 4-Mercaptophenylboronic acid (4-MPBA) was introduced as a probe molecule. Leveraging the high binding affinity between 4-MPBA and fructose, fructose was effectively drawn into the near-field hotspot regions of the nanoparticles. This unique approach enabled the identification of fructose enantiomers even in complex environments. Notably, the complex surface architecture and needle-like tips of the nanoparticles contributed to exceptional electromagnetic enhancement performance, resulting in ultra-sensitive assay capabilities for fructose enantiomers. This study thus establishes an induction strategy for the rapid screening of food authenticity.