An Au@NH₂-MIL-125(Ti)-based multifunctional platform for colorimetric detections of biomolecules and Hg²

In this report, a novel nanocomposite of highly dispersed Au nanoparticles deposited on NH₂-MIL-125(Ti) was designed and proposed as a peroxidase-like mimic. Compared with individual Au nanoparticles and NH₂-MIL-125(Ti), the peroxidase-like nanozyme exhibits enhanced peroxidase-like activity. Moreover, kinetic analysis reveals that the as-prepared nanozyme has lower K_m values and stronger affinity towards both substrates than the natural horseradish peroxidase (HRP). The detection limits of the multifunctional platform for H₂O₂, cysteine and Hg²⁺ are down to 0.24 μM, 0.14 μM and 100 nM, respectively. This work provides rapid and sensitive colorimetric detection strategies for small biomolecules and Hg²⁺, which have great potential for application in biosensors and biotechnology.