Mn-doped single atom nanozyme composited Au for enhancing enzymatic and photothermal therapy

As an emerging technology, nanocatalytic medicine attracts much attention, especially the ones according to the enzymatic reaction by using excess H₂O₂ in the tumor. Among various candidates, single-atom catalyst (SAC) revealed unique and outstanding redox reaction performance, since the active sites consisting of single metal atoms may achieve the maximum utilization of metal atoms and emerge obviously amplified reaction rate. Here we developed an M-N_x (M = Mn, Zn) center-based SAC with a hollow structure by calcination of Mn²⁺-doped zeolitic imidazolate frameworks (ZIF-8), and PEGylation was applied to improve the hydrophilicity. According to the enzymatic reaction, the M-N_x (M = Mn, Zn) centers have an inherent peroxidase-like activity to catalyze over-expressed H₂O₂ in the weak acidic tumor microenvironment and generate a large amount of toxic reactive oxygen species (ROS) like hydroxyl radicals for therapy. To keep efficient therapeutic output, we integrated the hollow SAC with Au which could expend the glucose in tumor and supply H₂O₂ as the substrate of peroxidase-like activity. Better yet, Au may boost the photothermal effect of SAC and offer another non-invasive photothermal therapy (PTT) to promote the effect of tumor removal. This platform provided a new idea for the construction of more efficient peroxidase-like activity in tumor therapy.