Investigation on the Peroxidase-Like Activity of Co₃O₄ Nanoparticles Adsorbed with Diverse DNA

In recent years, nanozymes have increasingly attracted the attention of researchers due to their low cost, high stability, and straightforward preparation when compared with natural enzymes. Furthermore, the biocompatibility of nanozymes has been enhanced through surface adsorption, hence broadening their application scope. In this work, Co₃O₄ nanozyme was adsorbed with diverse DNA, and the catalytic performance was significantly boosted compared with the pure Co₃O₄ nanozyme. Peroxidase-like activity assays revealed three key findings. First, the adsorption of single-stranded DNA proved to be more effective than that of double-stranded DNA. Second, the 50-nucleotide single-stranded DNA sequence yielded the stronger catalytic signal. Ultimately, guanine rich nucleotide exhibited the higher catalytic efficiency in single-stranded DNA and cytosine-guanine rich nucleotide exhibited the stronger catalytic efficiency in double-stranded DNA. The kinetic results of its catalytic activity showed that the catalysis of the adsorbed Co₃O₄ nanozyme followed the Michaelis-Menten kinetics. In parallel, the K_m value of 50-nucleotide single-stranded DNA adsorption was the lowest of diverse DNA, which was 6.11 mM and 54.8% of the pure Co₃O₄ nanozyme. These findings establish DNA adsorption as an effective strategy for enhancing the catalytic activity of Co₃O₄ nanozymes, presenting significant potential for applications in medical diagnostics and antioxidant-related fields.