Ru Atoms and Human Hemoglobin Confined in Nanoporous ZIF-67 as a Peroxidase-Mimicking Nanozyme for Cancer Identification

Precise diagnosis of a malignant tumor of a high degree is vital for highly effective prevention and the treatment of quality of human life, and abnormal levels of glucose or H2O2 have been regarded as potential biomarkers for their functions in cancer origin, progression, and occurrence of metastasis. The levels of glucose and H2O2 are remarkably different in cancer cells than in normal cells. Herein, an on-site colorimetric biosensor for cancer-related glucose and H2O2 is developed utilizing a porous ruthenium (Ru) and hemoglobin human (HSA)-doped imidazole-based metal–organic framework (Ru0.13/HSA0.06/ZIF-67) as an outstanding peroxidase-mimicking nanozyme. Specifically, Ru0.13/HSA0.06/ZIF-67 nanohybrids are prepared by in situ doping of HSA into ZIF-67 followed by an ion-exchange process. Taking advantage of the unique structures of natural enzymes and interface engineering, HSA and Ru are confined in continuous porous ZIF-67 to largely expose the active sites for the created nanopores. The obtained distinct structure considerably boosts peroxidase-mimicking activity. The colorimetric assay reveals that the peroxidase-mimicking capability of the Ru0.13/HSA0.06/ZIF-67 nanohybrid is superior to that of Fe-based natural enzymes and other Ru catalysts. Moreover, a Ru0.13/HSA0.06/ZIF-67 nanozyme-based colorimetric assay is constructed for detecting glucose and H2O2 via a visible signal readout. The developed toolkit for the preparation of Ru0.13/HSA0.06/ZIF-67 nanozymes with peroxidase-mimicking performance offers an avenue for rationally designing distinct nanozymes and has the potential perspectives for clinical transformation in colorimetric analysis.