Single‐atom nanozymes (SAzymes) can effectively mimic the metal active centers of natural enzymes at the atomic level owing to their atomically dispersed active sites, thereby maximizing atom utilization efficiency and density of active sites. Hence, SAzymes can be considered the most promising candidates to replace natural enzymes. Herein, a PEGylated mesoporous Mn‐based single‐atom nanozyme (PmMn/SAE) employing a coordination‐assisted polymerization pyrolysis strategy that uses polydopamine for photothermal‐augmented nanocatalytic therapy is designed. PmMn/SAE exhibits excellent multiple enzymatic performance, including catalase‐like, oxidase‐like, and peroxidase (POD)‐like performance, due to the atomically dispersed Mn active species. As a result, PmMn/SAE not only catalyzes the decomposition of endogenous H2O2 to generate O2 for relieving hypoxia inside the tumor but also transfers electrons to O2 to produce superoxide radicals to kill tumor cells. Meanwhile, PmMn/SAE is able to trigger Fenton‐like reactions to generate highly toxic hydroxyl radicals to induce cancer cell apoptosis. The POD‐like catalytic mechanism of mMn/SAE is revealed using experimental results and density functional theory. Furthermor, PmMn/SAE shows good photothermal conversion efficiency (η = 22.1%) in the second near‐infrared region (1064 nm). Both the in vitro and in vivo experimental results indicate that PmMn/SAE can effectively kill cancer cells through photothermal‐enhanced catalytic therapy.

Utilizing semiconductors to catalyze N2 into NH3 has brought great promise in alleviating the issue of energy shortage. However, the wide band gap and high recombination rate of photogenerated (e-/h+)...

Biomimetic nanozyme with natural enzyme-like activities has drawn extensive attention in cancer therapy, while its application was hindered by the limited catalytic efficacy in the complicated tumor microenvironment (TME). Herein, a hybrid biomimetic nanozyme combines polydopamine-decorated CuO with a natural enzyme of glucose oxidase (GOD), among which CuO is endowed with a high loading rate (47.1%) of GOD due to the elaborately designed hollow mesoporous structure that is constructed to maximize the cascade catalytic efficacy. In the TME, CuO could catalyze endogenous H2O2 into O2 for relieving tumor hypoxia and improving the catalytic efficacy of GOD. Whereafter, the amplified glucose oxidation induces starvation therapy, and the generated H2O2 and H+ enhance the catalytic activity of CuO. Significantly, the tumor-specific chemodynamic therapy (CDT) could be realized when CuO degraded into Cu2+ in acidic and reductive TME. Furthermore, the photothermal therapy with high photothermal conversion efficiency (30.2%) is achieved under NIR-II laser (1064 nm) excitation, which could reinforce the generation of reactive oxygen species (•OH and •O2 –). The TME initiates the biochemical reaction cycle of CuO, O2, and GOD, which couples with an NIR-II-induced thermal effect to realize O2-promoted starvation and photothermal–chemodynamic combined therapy. This hybrid biomimetic nanozyme enlightens the further development of nanozymes in multimodal cancer therapy.

Rare earth (RE)-based inorganic upconversion nanoparticles (UCNPs) have huge potency for applications varying from bioimaging to theranostics of tumors. For these applications, it is of great importance that UCNPs be expelled innocuously from a living body during a rational period of time after executing their diagnostic and/or therapeutic tasks. Despite great efforts to modulate biodegradability, a reasonable biodegradation rate for currently available UCNPs in weakly alkaline physiochemical buffers has not yet been realized. Herein, to achieve a tunable biodegradation rate for UCNPs, a class of core–shell-structured nanoparticles is invented by heteroepitaxially growing a CaF2:Yb shell with varying Zr4+ doping content on a biodegradable Na3ZrF7:Yb,Er core. The CaF2:Yb,Zr shell can not only enhance the emission intensity but also ensure the overall biodegradation of the nanocrystals. The degradation rate of core–shell UCNPs can be easily modulated by changing the Zr4+ doping content in the shell, and the degradation rate is pH-responsive; thus, tumor acidity-triggered degradation can be realized. When sodium alginate (SA)-modified UCNPs are used for the bioimaging of tumors, the intracellularly degraded metal ions and the released SA molecules can self-assemble through a coordination cross-linking effect, thereby improving the tumor retention of the nanosystems. These discoveries will unequivocally promote the future clinical applications of RE-based UCNPs.

The lanthanide-doped nanoparticles with upconversion and NIR-II downconversion dual-mode emissions were coated with copper and manganese silicate nanospheres and modified with sodium alginate for NIR-II imaging and dynamic therapy.