Flower-Like Nanozymes with Large Accessibility of Single Atom Catalysis Sites for ROS Generation Boosted Tumor Therapy

The use of reactive oxygen species (ROS) generators based on single-atom catalysts (SACs) has been an emerging strategy for mediating tumor therapy, however, the current systems suffer from low mass transport efficiency. Here, a novel strategy of morphology fragmentation is developed to fabricate flower-like SAC nanozymes with greatly improved 3D accessibility of active sites. Specifically, the coordinationally polymerized zeolite imidazole framework acts as a polyphenol oxidase-like enzyme to catalyze the in situ polymerization of polydopamine (PDA) which leads to blockage of micropores and crosslinking of the morphology-deteriorated ZIF nanosheets. The protective carbonization by PDA results in SAC nanozymes (C-NFs) with plenty of reopened micropores and defect mesopores (approximate to 4 nm) in the nanopetals, large interpetal pore space (approximate to 39 nm), high surface area (388 m(2) g(-1)), as well as an ultrahigh loading metal atoms (27.3 wt%). Subsequently, a superior peroxidases-like activity (36.6-fold increment in the turnover frequency) facilitates significantly strengthened ROS generation and damage of biomolecules. Moreover, the employment of apoferritin modification/loading leads to particle dispersion in solution and concomitant drug loading. The following cancer cell re-sensitization is proven to be advantageous for boosting ROS-facilitated treatment of drug-resistant tumors, opening up new avenues for ROS therapy.

Automated summary

Utilizing a novel morphology fragmentation strategy, flower-like SAC nanozymes were fabricated with improved 3D accessibility of active sites, enhancing ROS generation and biomolecule damage. This approach opens up new avenues for ROS therapy by promoting re-sensitization of drug-resistant tumors.