Multiplex Surface-Enhanced Raman Scattering Identification and Quantification of Urine Metabolites in Patient Samples within 30 Minutes

Successful translation of laboratory-based surface-enhanced Raman scattering (SERS) platforms to clinical applications requires multiplex and ultratrace detection of small metabolites from a complex biofluid. However, these metabolites exhibit low Raman scattering cross-sections and do not possess specific affinity to plasmonic nanoparticle surfaces, significantly increasing the challenge of detecting them at low concentrations. Herein, a ‘confine-and-capture’ approach is demonstrated for multiplex detection of two families of urine metabolites correlated with miscarriage risks, 5β-pregnane-3α,20α-diol-3α-glucuronide and tetrahydrocortisone. To enhance SERS signals by 1012-fold, specific nanoscale surface chemistry is used for targeted metabolite capture from a complex urine matrix prior to confining them on a superhydrophobic SERS platform. Applying chemometrics, including principal component analysis and partial least square regression, enables conversion of molecular fingerprint information into quanti...