A stable photoactive metal–organic framework UiO-66(Zr) sensitized by adsorbed or directly added rhodamine B dye exhibited photocatalytic activity for hydrogen evolution under visible-light illumination (λ ≥ 420 nm). Using Pt as a co-catalyst, the adsorbed and directly added dye extremely enhanced the photocatalytic activity to 30 and 26 times the value afforded by bare Pt@UiO-66(Zr), respectively.
We demonstrated that embedding of CdS on MOFs could significantly increase the photocatalytic efficiency of CdS for visible light-driven hydrogen production.
The construction of efficient enzyme mimetics for the hydrolysis of peptide bonds in proteins is challenging due to the high stability of peptide bonds and the importance of proteases in biology and industry. Metal-organic frameworks (MOFs) consisting of infinite crystalline lattices with metal clusters and organic linkers may provide opportunities for protease mimic which has remained unknown. Herein, we report that Cu2(C9H3O6)4/3 MOF (which is well known as HKUST-1 and denoted as Cu-MOF here), possesses an intrinsic enzyme mimicking activity similar to that found in natural trypsin to bovine serum albumin (BSA) and casein. The Michaelis constant (Km) of Cu-MOF is about 26,000-fold smaller than that of free trypsin indicating a much higher affinity of BSA for Cu-MOF surface. Cu-MOF also exhibited significantly higher catalytic efficiency than homogeneous artificial metalloprotease Cu(II) complexes and could be reused for ten times without losing in its activity. Moreover, Cu-MOF was successfully used to simulate trypsinization in cell culture since it dissociated cells in culture even without EDTA.
Early diagnosis and the timely treatment of cancer are key to improving patient survival rates at present. Metal–organic frameworks (MOFs) consisting of infinite crystalline lattices with metal clusters and organic linkers may provide opportunities for the detection of cancer cells which have remained undiagnosed. Herein, we report that Fe-MIL-101 possesses an intrinsic enzyme mimicking activity similar to that found in natural horseradish peroxidase and shows highly catalytic activity even at neutral pH. The Michaelis constant (Km) of Fe-MIL-101 with H2O2 as the substrate is about 616-fold (at pH 4.0) and 20-fold (at pH 7.0) smaller than free natural horseradish peroxidase (HRP), indicating a much higher affinity for H2O2 than HRP and most of the peroxidase mimetics. Moreover, Fe-MIL-101 was successfully used to detect cancer cells by conjugating folic acid onto Fe-MIL-101 without any surface modification. The detection limit of the method for HeLa cells was estimated to be 50 cells and the reaction colour produced with 10 cells could also be observed by the naked eye. The proposed method holds considerable potential for simple, sensitive, universal, and specific cancer cell detection.