Aptamer-Driven Nanozyme-SERS Bifunctional Sensors with Enrichment Separation Effect for Ultrasensitive Detection of Liver-Fibrosis-Related Biomarkers.

Liver fibrosis represents the earliest and most critical pathological stage in the progression of various liver diseases. Its accurate detection is paramount for preventing transformation into cirrhosis and hepatocellular carcinoma. Here, we report an aptamer-driven nanozyme-catalyzed surface-enhanced Raman scattering (SERS) dual-functionality sensor. By integrating magnetic enrichment and separation effects, we achieve multiple signal amplification, enabling the ultrasensitive detection of fibrosis-associated miR-34a. In this study, we synthesized gold-platinum nanoparticles (Au@Pt NPs) exhibiting high peroxidase activity and intrinsic surface-enhanced Raman scattering (SERS) properties. These were surface-modified with the complementary strand (H₁) of an aptamer to serve as nanozyme probes. Fe₃O₄ modified with an aptamer (cDNA) was employed as the capture substrate. The assembly and dissociation of Au@Pt NPs with Fe₃O₄ are driven by the competitive binding of the target and H₁ to the cDNA. The degree of aggregation of Au@Pt NPs on Fe₃O₄ directly enhances the catalytic oxidation of oxTMB. Moreover, the synergistic interaction between the local surface plasmon resonance effect of nanozyme probes and capture substrates with external magnetic enrichment achieves exponential amplification of oxTMB signals. Based on this strategy, the dual-functional sensor demonstrates robust detection performance, with a limit of detection (LOD) as low as 0.27 fM and a detection time of merely 12 min. Moreover, this nanozyme-SERS dual-functional sensor exhibits strong specificity and resistance to interference, with detection results demonstrating high concordance with qRT-PCR. This research provides a robust method for detecting serum miRNAs in liver fibrosis and paves new pathways for the clinical translation of the SERS-nanozyme combined technology.