Reactive oxygen species (ROS) are generated and consumed in living organism for normal metabolism. Paradoxically, the overproduction and/or mismanagement of ROS have been involved in pathogenesis and progression of various human diseases. Here, we reported a two-dimensional (2D) vanadium carbide (V2C) MXene nanoenzyme (MXenzyme) that can mimic up to six naturally-occurring enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione peroxidase (GPx), thiol peroxidase (TPx) and haloperoxidase (HPO). Based on these enzyme-mimicking properties, the constructed 2D V2C MXenzyme not only possesses high biocompatibility but also exhibits robust in vitro cytoprotection against oxidative stress. Importantly, 2D V2C MXenzyme rebuilds the redox homeostasis without perturbing the endogenous antioxidant status and relieves ROS-induced damage with benign in vivo therapeutic effects, as demonstrated in both inflammation and neurodegeneration animal models. These findings open an avenue to enable the use of MXenzyme as a remedial nanoplatform to treat ROS-mediated inflammatory and neurodegenerative diseases.

The intrinsic deficiencies of nanoparticle‐initiated catalysis for biomedical applications promote the fast development of alternative versatile theranostic modalities. The catalytic performance and selectivity are the critical issues that are challenging to be augmented and optimized in biological conditions. Single‐atom catalysts (SACs) featuring atomically dispersed single metal atoms have emerged as one of the most explored catalysts in biomedicine recently due to their preeminent catalytic activity and superior selectivity distinct from their nanosized counterparts. Herein, an overview of the pivotal significance of SACs and some underlying critical issues that need to be addressed is provided, with a specific focus on their versatile biomedical applications. Their fabrication strategies, surface engineering, and structural characterizations are discussed briefly. In particular, the catalytic performance of SACs in triggering some representative catalytic reactions for providing the fundamentals of biomedical use is discussed. A sequence of representative paradigms is summarized on the successful construction of SACs for varied biomedical applications (e.g., cancer treatment, wound disinfection, biosensing, and oxidative‐stress cytoprotection) with an emphasis on uncovering the intrinsic catalytic mechanisms and understanding the underlying structure–performance relationships. Finally, opportunities and challenges faced in the future development of SACs‐triggered catalysis for biomedical use are discussed and outlooked.

The hypoxic tumor microenvironment severely lowers the therapeutic efficacy of oxygen-dependent anticancer modalities because tumor hypoxia hinders the generation of toxic reactive oxygen species. Here we report a thermodynamic cancer-therapeutic modality that employs oxygen-irrelevant free radicals generated from thermo-labile initiators for inducing cancer cell death. A free radical nanogenerator was engineered via direct growth of mesoporous silica layer onto the surface of two-dimensional Nb 2 C MXene nanosheets toward multifunctionality, where the mesopore provided the reservoirs for initiators and the MXene core acted as the photonicthermal trigger at the near-infrared-II biowindow (NIR-II). Upon illumination by a 1064 nm NIR-II laser, the photothermal-conversion effect of Nb 2 C MXene induced the fast release and quick decomposition of the encapsulated initiators (AIPH) to produce free radicals, which promoted cancer cell apoptosis in both normoxic and hypoxic microenvironment. Systematic in vitro and in vivo evaluations have demonstrated the synergistic-therapeutic outcome of this intriguing photonic nanoplatform-enabled thermodynamic cancer therapy for completely eradicating the 4T1 tumors without recurrence by NIR-II laser irradiation. This work pioneers the thermodynamic therapy for oxygen-independent cancer treatment by photonic triggering at the NIR-II biowindow.

A novel cancer cell lysosome-targetable multifunctional NO-delivery nanoplatform (Lyso-Ru-NO@FA@C-TiO2) (1) was developed. It selectively targets folate-receptor overexpressed cancer cells and specifically locates within the lysosome organelle to which NO and reactive oxygen species are simultaneously released upon 808 nm NIR light irradiation. The dual-targeted nanoplatform (1) demonstrated the highest anticancer efficacy compared with nontargeted counterparts under NIR light sensitization.

Malignant bone tumors are one of the major serious diseases in clinic. Inferior reconstruction of new bone and rapid propagation of residual tumor cells are the main challenges to surgical intervention. Herein, a bifunctional DTC@BG scaffold for near‐infrared (NIR)‐activated photonic thermal ablation of osteosarcoma and accelerated bone defect regeneration is engineered by in situ growth of NIR‐absorbing cocrystal (DTC) on the surface of a 3D‐printing bioactive glass (BG) scaffold. The prominent photothermal conversion performance and outstanding bone regeneration capability of DTC@BG scaffolds originate from the precise tailoring of the bandgap between the electron donors and acceptors of DTC and promote new bone growth performance of BG scaffolds. DTC@BG scaffolds not only significantly promote tumor cell ablation in vitro, but also effectively facilitate bone tumor suppression in vivo. In particular, DTC@BG scaffolds exhibit excellent capability in stimulating osteogenic differentiation and angiogenesis, and finally promote newborn bone formation in the bone defects. This research represents the first paradigm for ablating osteosarcoma and facilitating new bone formation through precise modulation of electron donors and acceptors in the cocrystal, which offers a new avenue to construct high‐efficiency therapeutic platforms based on cocrystal strategy for ablation of malignant bone tumor.

The potential of the cluster regularly interspaced short palindromic repeat (CRISPR)‐associated protein 9 (Cas9)‐based therapeutic genome editing is severely hampered by the difficulties in precise regulation of the in vivo activity of the CRISPR‐Cas9 system. Herein, sono‐controllable and reactive oxygen species (ROS)‐sensitive sonosensitizer‐integrated metal–organic frameworks (MOFs), denoted as P/M@CasMTH1, are developed for augmented sonodynamic therapy (SDT) efficacy using the genome‐editing technology. P/M@CasMTH1 nanoparticles comprise singlet oxygen (1O2)‐generating MOF structures anchored with CRISPR‐Cas9 systems via 1O2‐cleavable linkers, which serve not only as a delivery vector of CRISPR‐Cas9 targeting MTH1, but also as a sonoregulator to spatiotemporally activate the genome editing. P/M@CasMTH1 escapes from the lysosomes, harvests the ultrasound (US) energy and converts it into abundant 1O2 to induce SDT. The generated ROS subsequently trigger cleavage of ROS‐responsive thioether bonds, thus inducing controllable release of the CRISPR‐Cas9 system and initiation of genome editing. The genomic disruption of MTH1 conspicuously augments the therapeutic efficacy of SDT by destroying the self‐defense system in tumor cells, thereby causing cellular apoptosis and tumor suppression. This therapeutic strategy for synergistic MTH1 disruption and abundant 1O2 generation provides a paradigm for augmenting SDT efficacy based on the emerging nanomedicine‐enabled genome‐editing technology.

The integration of chemotherapy and photodynamic therapy (PDT) in a single delivery system is highly desirable for enhancing anticancer therapeutic efficacy. Herein, two cyclometalated Ir(III) complex-constructed micelles FIr-1 and FIr-2 were demonstrated for glutathione (GSH) activated targeted chemotherapy and PDT. The cyclometalated Ir(III) complexes were prepared by conjugating phosphorescent Ir(III) compounds with chemotherapeutic drug camptothecin (CPT) through GSH responsive disulfide bond linkages, and the Ir(III) complexes were then assembled with amphiphilic surfactant pluronic F127 via noncovalent encapsulation to afford micelles. The surfaces of the micelles were further decorated with folic acid as a targeting group. The micelles showed intense fluorescence that renders them with excellent real-time imaging capability. The release of free anticancer drug CPT from the micelles was realized through GSH-activated disulfide bond cleavage in tumor cells. In addition, the micelles were capable of generating singlet oxygen used for PDT upon visible light irradiation. On account of having folic acid targeting ligand, the micelles displayed greater cellular accumulation in folate receptor (FR) overexpressed HeLa cells than FR low-expressed MCF-7 cells, leading to selective cancer cell killing effect. As compared with solo therapeutic systems, the micelles with targeted combinational chemotherapy and PDT presented superior potency and efficacy in killing tumor cells at a low dosage. On the basis of these findings, the multifunctional micelles could serve as a versatile theranostic nanoplatform for cancer cell targeted imaging and combinational therapy.

Development of organic theranostic agents that are active in the second near-infrared (NIR-II, 1000–1700 nm) biowindow is of vital significance for treating deep-seated tumors. However, studies on organic NIR-II absorbing agents for photo-to-heat energy-converting theranostics are still rare simply because of tedious synthetic routes to construct extended π systems in the NIR-II region. Herein, we design a convenient strategy to engineer highly stable organic NIR-II absorbing theranostic nanoparticles (Nano-BFF) for effective phototheranostic applications via co-assembling first NIR (NIR-I, 650–1000 nm) absorbing boron difluoride formazanate (BFF) dye with a biocompatible polymer, endowing the Nano-BFF with remarkable theranostic performance in the NIR-II region. In vitro and in vivo investigations validate that Nano-BFF can serve as an efficient theranostic agent to achieve photoacoustic imaging guided deep-tissue photonic hyperthermia in the NIR-II biowindow, achieving dramatic inhibition toward orthotopic hepatocellular carcinoma. This work thus provides an insight into the exploration of versatile organic NIR-II absorbing nanoparticles toward future practical applications.