Confinement effect of zirconium metal–organic frameworks derived enhanced oxidase-like activity and stability of gold nanoclusters for biosensing

Gold nanoclusters (AuNCs), as an attractive material in heterogeneous catalysis, exhibit great potential in biosensing and biomedicine. However, controllable regulation of catalytic activity and preferable stabilization of AuNCs remain challenging. Benefiting from porous structures and ultrahigh specific surfaces, metal–organic frameworks (MOFs) have shown promising potential in the tailoring of catalytic activity and improving the stability of AuNCs. However, preferable catalytic activity and excellent stability are still challenging, due to the easy leaching of AuNCs from MOFs. Enhancing the combination between AuNCs and MOFs is of great significance. Herein, biomimic nanozymes of AuNCs@UiO-68 were designed through strong coordination between Zr atoms of the MOFs and phosphonate O atoms of DNA backbones from the DNA-templated AuNCs. Compared with control materials of AuNCs and AuNCs/UiO-68, a significant enhancement of oxidase-mimicking activity was achieved in AuNCs@UiO-68, owing to the confinement effect of Zr-MOFs. Additionally, it was found that the catalytic activity of AuNCs could be regulated by altering ligands of the Zr-MOFs. Based on the favorable catalytic activity of AuNCs@UiO-68, a highly sensitive and selective detecting platform for small uremic toxin molecule of hydroquinone was established, with a low detection limit of 0.85 μM. The stability of AuNCs was greatly improved by the proposed synthetic strategy. Besides, preferable and controllable catalytic activity was also obtained, attributed to the confinement effect of MOFs. This work provides a new way for rational regulation of catalytic activity and ameliorating the stability of metal clusters based nanozymes.