Ir Cluster-Anchored MOFs as Peroxidase-Mimetic Nanoreactors for Diagnosing Hydrogen Peroxide-Related Biomarkers

Exploring multifaceted and highly sensitive biosensors is a major challenge in biotechnology and medical diagnosis. Here, we create a new iridium (Ir) cluster-anchored metal-organic framework (MOF, namely, IrNCs@Ti-MOF via a coordination-assisted strategy) as a peroxidase (POD)-mimetic nanoreactor for colorimetrically diagnosing hydrogen peroxide-related biomarkers. Owing to the IrNCs-N/O coordination of Ti-MOF and unique enzymatic properties of Ir clusters, the IrNCs@Ti-MOF exhibits exceptional and exclusive POD-mimetic activities (Km = 3.94 mM, Vmax = 1.70 mu M s-1, and turnover number = 39.64 x 10-3 s-1 for H2O2), thus demonstrating excellent POD-mimetic detecting activity and also super substrate selectivity, which is considerably more efficient than recently reported POD mimetics. Colorimetric studies disclose that this IrNCs@Ti-MOF-based nanoreactor shows multifaceted and efficient diagnosing activities and substrate selectivity, such as a limit of detection (LOD): 14.12 mu M for H2O2 at a range of 0-900 mu M, LOD: 3.41 mu M for L-cysteine at a range of 0-50 mu M, and LOD: 20.0 mu M for glucose at a range of 0600 mu M, which enables an ultrasensitive and visual determination of abundant H2O2-related biomarkers. The proposed design will not only provide highly sensitive and cheap colorimetric biosensors in medical resource-limited areas but also offer a new path to engineering customizable enzyme-mimetic nanoreactors as a powerful tool for accurate and rapid diagnosis.

Automated summary

In this study, a new nanoreactor was created by mimicking peroxidase to meet the needs of bio-diagnosis. The nanoreactor showed exceptional diagnostic activity and high substrate selectivity, enabling ultrasensitive and visual detection of various biomarkers.