Nanozyme-catalyzed SERS sensor combined with a competitive recognition strategy for diabetic retinopathy-associated...

This study developed a new type of sensor that integrates the bifunctional characteristics of nanozymes with surface-enhanced Raman scattering (SERS) technology for the efficient detection of vascular endothelial growth factor (VEGF) associated with diabetic retinopathy (DR). The sensor uses Au-coated Si nanopillar arrays (Au/SiNPA) as a substrate, whose high-density nanostructure can produce uniform SERS "hot spots", significantly improving signal stability. Additionally, Au@Pd nanorods (Au@Pd NRs) have both peroxidase (POD)-like activity and SERS enhancement effects, which can efficiently catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to generate the characteristic Raman signal molecule oxTMB. This study employs a competitive recognition strategy, achieving VEGF detection through a simple sample addition reaction, thereby avoiding the complex labeling steps and invasive procedures associated with traditional methods. When VEGF in serum competitively displaces the probe, the oxTMB signal correspondingly weakens. By quantifying this signal change, rapid and highly sensitive detection can be achieved within 12 min, with a detection limit as low as 0.583 pg/mL. Validation using a DR rat model confirmed the sensor's accuracy, with results highly consistent with enzyme-linked immunosorbent assay (ELISA). This sensor offers a rapid, convenient, and highly sensitive solution for early screening of DR and dynamic monitoring of VEGF, demonstrating significant clinical application potential.