Investigation\nfor Regulation of a DNA-Programmed Bimetallic\nNanozyme and Its Biosensing Applications

The DNA-mediated growth strategy of bimetallic nanozymes\nis considered\nas an effective approach to regulate their peroxidase activity via\ntuning the morphology and nanostructure. Albeit important, its biosensing\napplication in rational methods’ design and performance improvement\nis limited due to the deficiency of a systematic understanding of\nthe interactions between DNA and nanomaterials used. Herein, four\nhomo-oligonucleotides as capping ligands were employed to functionalize\nthe bimetallic nanozymes, where Pt nanoparticles (PtNPs) were in situ\nsynthesized onto DNA-bound Au nanorods (AuNRs), and the effects of\nDNA with different lengths on the state of bimetallic nanozymes were\ninvestigated in detail. It was found that the aggregation of AuNRs\nobviously depended on the variety and number of DNA oligonucleotides\nwith the absorbance ratio at 810 and 525 nm (A810/A525), ranking as\nfollows: AuNRs/A10/PtNPs > AuNRs/G10/PtNPs > AuNRs/C10/PtNPs\n≫\nAuNRs/T10/PtNPs, which is consistent with the value of <i>K</i><sub>m</sub> for TMB, indicating that the dispersal/aggregation of\nthe AuNRs is closely related to the deposition and growth of PtNPs,\nthereby significantly influencing their peroxidase activity. According\nto our discoveries, a novel colorimetric array platform was fabricated\nusing the above four types of DNA-encoded Pt–Au bimetallic\nnanozymes as sensing elements for sensitively discriminating the five\nbiological thiols (l-cys, GSH, Hcy, DTT, and Cys–Gly)\nand identifying the normal cells/tumor cells, respectively. Our work\nprovides a new insight into DNA-programmed bimetallic nanozyme regulation\nand broadens its sensing applications.