Light-Responsive Metal-Organic Framework as an Oxidase Mimic for Cellular Glutathione Detection.

Nanomaterials with enzyme-like characteristics (nanozymes) have been developed to mimic enzymes because of their low cost, high stability, and large-scale production. By using light as an external stimulation, one can modulate nanozymes' catalytic activities with controlled spatial and temporal precision. A few inorganic photoactive materials have been investigated to construct light-responsive oxidase-like nanozymes. However, these materials suffered from limited absorbance of visible light. To address this challenge, herein we have developed a photosensitized metal-organic framework (PSMOF) by using a derivative of Ru(bpy)32+ with stronger visible-light absorption as a PS linker. The PSMOF exhibited excellent oxidase-like activity, which could be modulated by switching light on and off. Moreover, the PSMOF was used to detect glutathione levels in both normal and cancer cells with good selectivity and high sensitivity. This study not only provides a smart strategy to modulate nanozymes' activities but also broadens the sensing applications of nanozymes.