Catalytic hairpin assembly-powered nanozyme-SERS dual-function sensing system for ultrasensitive detection of gastric precancerous lesions.

In this study, we developed a target-mediated 3,3',5,5'-tetramethylbenzidine (TMB) responsive bifunctional sensing system. This work used Au nano pumpkin arrays (Au NPAs) as a high-performance plasma matrix and platinum coated Au nanorods (Au@Pt NRs) as nanoenzyme probes, a target triggered catalytic hairpin self-assembly (CHA) amplification strategy is introduced to construct a "dual functional" sensing system with efficient peroxidase (POD)-like activity and excellent surface-enhanced Raman scattering (SERS) enhancement ability. Au@Pt NRs were induced to be assembled on the surface of Au NPAs by CHA technique when the target was present. The sensing system catalyzed the TMB to generate oxidized TMB (oxTMB) with strong SERS signals, and the SERS signals were further amplified by CHA. The sensing system demonstrated excellent analytical performance, achieving ultrasensitive detection of miR-196b and miR-221, tumor markers of gastric precancerous lesions, with detection limit as low as aM level. It also had the capability of simultaneous dual-target detection, which had shown satisfactory clinical utility and accuracy in the detection of actual serum samples. Introducing Receiver Operating Characteristic (ROC) curves to evaluate the diagnostic efficacy of sensing system in detecting precancerous lesions of gastric cancer, the area under the curve (AUC) values for target combination diagnosis were 0.954 and 0.957, respectively. Therefore, the proposed dual function sensing system has broad application prospects in the clinical detection of precancerous lesions of gastric cancer.