Dendritic Mesoporous Silica Nanoparticle-Tuned High-Affinity MnO2 Nanozyme for Multisignal GSH Sensing and Target Cancer Cell Detection

Development of multifunctional enzymatic nanomaterials with rapid and sensitive characteristics for glutathione determination is extremely urgent for early cancer diagnosis. Herein, a core–shell ultrasensitive nanozyme (denoted as CPT/DM-FA) for triple-mode glutathione sensing and specific in vitro cancer detection is constructed. The dendritic mesoporous silica nanoparticle (DMSN) core not only acts as a camptothecin carrier, but also offers the nanoplatform to synthesize the MnO2 shell. Due to the DMSN-regulated high dispersion of MnO2, the atomic utilization efficiency of MnO2 is surprisingly enhanced, and leads to notable enzymatic activity with Km 0.136 μM and Vmax 0.59 μM/s. In addition, by integrating the quenching ability based on fluorescence resonance energy transfer and oxidase-mimic-mediated 1O2, O2– generation of MnO2, the fluorescence, UV–vis, and colorimetric method for glutathione sensing is established with a comprehensive linear range from 2 to 250 μM and a limit of detection of 0.654 μM. Besides, after surface folic acid modification, the CPT/DM-FA could also specifically detect cancer cells from 25 to 1 50 000 through the color reaction of 3,3′,5,5′-tetramethylbenzidine. We believe this nanozyme could afford a potential strategy to amplify the nanozyme activity for further biomedical applications.