Moisture-resistant and green cyclodextrin metal-organic framework nanozyme based on cross-linkage for visible detection of cellular hydrogen peroxide.

A moisture-resistant and green cyclodextrin metal-organic framework (CD-MOF) nanosheet has been prepared via an one-pot antisolvent synthesis procedure. After the treatment of in situ chemical cross-linkage, the two-dimensional (2D) cross-linked CD-MOF exhibited both peroxidase (POD) and oxidase (OXD) enzymatic activities, as well as hydrolytic stability. On the basis of its POD mimics function, the proof-of-concept biosensors were constructed to realize the colorimetric detection for HO and glucose, respectively. In vitro cytotoxicity experiments showed that the 2D cross-linked CD-MOF nanozymes still maintained excellent biocompatibility even at a concentration reaching up to several mg/mL. The in situ colorimetric detection of HO secreted by HepG2 cells further confirmed its promising biocompatibility, showing its great promises as label-free colorimetric probe in early cancer detection and pathological process monitoring.