Non-invasive monitoring of hyperuricemia via a flexible SERS sensor with ultrahigh sensitivity

A high-performance, flexible surface-enhanced Raman scattering (SERS) sensing platform designed to detect key hyperuricemia (HUA) biomarkers in non-invasive biofluids is presented. The platform employs a bimetallic nanocomposite hydrogel fabricated via a semi-interpenetrating polymer network, wherein hydroxyethyl cellulose-stabilized gold nanorods are integrated with in situ-reduced silver nanoparticles from oxidized sodium alginate within a sodium alginate/polyacrylamide hybrid network. The hydrogel SERS substrate exhibits outstanding mechanical properties with a tensile strain of up to 911.37% and excellent swelling behavior, achieving equilibrium swelling ratios of 1919.74% in deionized water and 1822.97% in artificial urine. It achieves detection limits of 2.09 × 10^- 10 M for uric acid, 1.70 × 10^- 10 M for xanthine, and 2.14 × 10^- 9 M for hypoxanthine. Spike-and-recovery experiments in artificial urine confirm recoveries consistently above 90%, validating the substrate's excellent accuracy and reproducibility in complex biological matrices. Collectively, this work provides a novel and reliable approach for advancing non-invasive, real-time monitoring of HUA.