A multifunctional Pt/DMSN nanozyme-based colorimetric-fluorescence sensing platform for breast cancer detection

Nanozyme-linked immunosorbent assay has emerged as a promising strategy for sensitive biosensing. However, the catalytic activity and stability of nanozymes affect the accuracy of immunosorbent assays. In this study, we synthesized a Pt/DMSN nanozyme with peroxidase-mimicking activity, which effectively catalyzed the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidin (TMB) in the presence of hydrogen peroxide. Capitalizing on its peroxidase-like activity, the Pt/DMSN nanozyme was functionalized with dual-fluorescent recognition elements (HER2-mAbs and sk6Ea aptamers) to establish a nanozyme-linked immunosorbent assay platform, which exhibited catalytic stability and substrate affinity comparable to horseradish peroxidase. The resulting Multi-Pt/DMSN platform was used to selectively distinguish HER2-positive breast cancer cells from luminal A, triple-negative breast cancer subtypes, and non-neoplastic cells, achieving a detection limit of 50 HER2-positive cells within 30 min. The combination of robust enzyme-like activity and tumor-targeting properties enables fluorescence imaging, providing dual-mode diagnostic functionality. This work presents a prospective platform for differentiating breast cancer subtypes in early diagnosis.