Engineering 2D Multienzyme-Mimicking Pyroptosis Inducers for Ultrasound-Augmented Catalytic Tumor Nanotherapy

Spatial-Constraint Modulation of Intra/Extracellular Reactive Oxygen Species by Adaptive Hybrid Materials for Boosting Pyroptosis and Combined Immunotherapy of Breast Tumor

Pyroptosis-immunotherapy has potential for triple-negative breast cancer treatment, but its efficacy is limited by insufficient pyroptosis activation and the need for phased, balanced, and spatially controlled activation of active species during long-term treatment. To reconcile intracellular/extracellular demands in tumor ablation, a nanoparticle-hydrogel hybrid enabling spatiotemporal reactive oxygen species (ROS) modulation is engineered. An open-shell sonosensitizer with unpaired electrons in its molecular orbitals is prepared by chelating Cu2⁺ with TCPP. These sonosensitizers are undergoing bovine serum albumin mediated biomineralization to form calcium phosphate particles and are incorporated into an injectable hydrogel through Schiff base crosslinking between dopamine-functionalized oxidized hyaluronic acid and gallic acid-modified chitosan. After intratumoral injection, nanoparticles endocytosed into tumor cells undergo acidic degradation, releasing calcium ions and GSH-activatable sonosensitizers. Calcium overload synergizes with ultrasound-mediated oxidative stress to induce mitochondrial damage and pyroptosis, while adhesive hydrogels retained in the extracellular matrix control excessive secondary ROS levels to protect oxidation-sensitive entities. This dual-action mechanism enhances the overall therapeutic effect by combining immediate tumor killing with long-term immune activation. This study provides a new route to hybrid material design, addressing the conflicting demands of short-term tumor ablation and long-term immune activation, overcoming the limitations of current pyroptosis-based immunotherapies.

Microwave-Responsive AlEu-MOFs Potentiate NLRP3-Mediated Pyroptosis via a "Triple Initiating" Tactic for Breast Cancer Microwave-Immunotherapy

Microwave thermotherapy is favored in clinical practice for breast cancer conservation strategies due to its minimally invasive characteristic. Nevertheless, the immunosuppressive tumor microenvironment (TME) significantly attenuates the therapeutic efficacy of anti-tumor immune response, posing challenges in effectively preventing tumor recurrence and metastasis. Pyroptosis, a recently identified form of programmed cell death triggered by inflammasomes, presents unique inflammatory and immunogenic properties that hold promise for cancer immunotherapy. Herein, microwave-responsive AlEu-MOFs are designed and synthesized to boost NLRP3-mediated pyroptosis via a "Triple Initiating" tactic for breast cancer microwave-immunotherapy. The potent microwave thermal effect of AEM facilitates the up-regulation of HSP90, thereby initiating NLRP3 expression. Concurrently, it induces mitochondrial dysfunction to generate substantial quantities of ROS, further enhancing NLRP3 expression to achieve a targeted amplification of microwave thermotherapy-induced pyroptosis. Simultaneously, the microwave-responsive directed anchoring release of highly active metal ions promotes the activation of the NLRP3 inflammasome jointly, ultimately inducing high-efficiency pyroptosis. This innovative "2M" (materials and methods) dual-pronged strategy not only significantly inhibits primary tumor proliferation, but also further impedes distant tumor progression and lung metastasis. This work provides a novel strategy to accurately and effectively achieve pyroptosis and offers a new approach to overcome the obstacles of clinical microwave thermotherapy.

Gallium-Magnesium Layered Double Hydroxide for Elevated Tumor Immunotherapy Through Multi-Network Synergistic Regulation

Immunotherapeutic efficacy is often limited by poor immunogenicity, immunosuppressive tumor microenvironment (TME), and cytoprotective mechanisms, leading to low immune activation. To this end, here, L-amino acid oxidase (LAAO) loaded gallium-magnesium layered double hydroxide (MG-LAAO) is prepared for significantly enhanced tumor immunotherapy through multi-network synergistic regulation. First, MG-LAAO induces tumor cell pyroptosis by initiating caspase-1/GSDMD and caspase-3/GSDME pathways, further triggering immunogenic cell death (ICD). Then the released Ga3+ induces mitochondrial iron overload, resulting in ferroptosis. In addition, MG-LAAO also hinders autophagy of tumor cells, and reshapes the immunosuppressive tumor microenvironment (TME) by neutralizing H+ and inhibiting lactic acid accumulation, thus destroying the cytoprotective mechanism and avoiding immune escape. Furthermore, this multi-network synergy further activates the cGAS-STING signaling pathway, generating powerful antitumor immunotherapy. This work highlights the critical role of synergies between autophagy block, pyroptosis, ferroptosis, and ICD in tumor immunotherapy, demonstrating the important role of this multi-network synergy in effectively overcoming immunosuppressive TME and enhancing immunogenicity. In particular, the mechanism of gallium-induced pyroptosis is revealed for the first time, providing theoretical support for the design of new materials for tumor immunotherapy in the future.

Bioinspired Fe3O4@Ag@ indocyanine green/adenosine triphosphate nanoenzyme in synergistic antibacterial performance

Metal-based nanoenzymes with excellent biocompatibility and stable chemical properties are an effective antimicrobial agent against bacterial resistance due to their radical-mediated catalysis. In this work, due to the pH of most bacterial infection sites being close to neutral, targeting the problem of Fe3O4@Ag difficulty in maintaining the catalytic activity of nanoenzymes in neutral environments, we prepare a novel multifunctional Fe3O4@Ag@ indocyanine green/adenosine triphosphate peroxidase nanoenzymes for synergistic antibacterial activity. ICG (Indocyanine Green) and ATP (Adenosine triphosphate) are adsorbed on the surface of Fe3O4@Ag through electrostatic adsorption to form its structure. The cell viability remained above 90%, indicating its good biocompatibility. By complexing ATP with nanoenzymes to participate in single electron transfer and binding with Fe (II), ATP promotes the sudden release of hydroxyl radical (·OH) from the system, successfully transferring Fe3O4@Ag the peroxidase activity of nanoenzymes extends to neutral pH. By utilizing ICG as a photosensitizer and a sonosensitizer, under the combined treatment of near-infrared light and ultrasound, the photodynamic therapy (PDT)/photothermal therapy (PTT)/sonodynamic therapy (SDT) functions can be achieved, achieving multifunctional synergistic antibacterial effects. In a neutral environment, its bactericidal efficiency against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) is 99.9% and 99.7%, respectively, providing a new multi-mode synergistic antibacterial strategy for bacterial infections.

Rational Design of Nanozymes for Engineered Cascade Catalytic Cancer Therapy

Nanozymes have shown significant potential in cancer catalytic therapy by strategically catalyzing tumor-associated substances and metabolites into toxic reactive oxygen species (ROS) in situ, thereby inducing oxidative stress and promoting cancer cell death. However, within the complex tumor microenvironment (TME), the rational design of nanozymes and factors like activity, reaction substrates, and the TME itself significantly influence the efficiency of ROS generation. To address these limitations, recent research has focused on exploring the factors that affect activity and developing nanozyme-based cascade catalytic systems, which can trigger two or more cascade catalytic processes within tumors, thereby producing more therapeutic substances and achieving efficient and stable cancer therapy with minimal side effects. This area has shown remarkable progress. This Perspective provides a comprehensive overview of nanozymes, covering their classification and fundamentals. The regulation of nanozyme activity and efficient strategies of rational design are discussed in detail. Furthermore, representative paradigms for the successful construction of cascade catalytic systems for cancer treatment are summarized with a focus on revealing the underlying catalytic mechanisms. Finally, we address the current challenges and future prospects for the development of nanozyme-based cascade catalytic systems in biomedical applications.

Engineered Metal-Organic Framework with Stereotactic Anchoring and Spatial Separation of Porphyrins for Amplified Ultrasound-Mediated Pyroptosis and Cancer Immunotherapy

Ultrasound-mediated reactive oxygen species (ROS) generation is pivotal in specifically inducing pyroptosis of tumor cells. However, the effectiveness of pyroptosis is generally hindered by the constraints of ROS generation efficiency. Herein, a new porphyrin-based metal-organic framework (Fe(TCPP)-MOF) was rationally designed via an innovative dual-solvent strategy to amplify ROS generation for ultrasound-controlled pyroptosis. The crystal structure of Fe(TCPP)-MOF was elucidated by continuous rotation electron diffraction technique, revealing its regular and rigid conformation. The porphyrin molecules were precisely oriented and firmly confined within the scaffold, effectively restricting intramolecular motion. The ample distance of 6.8 Å between two porphyrin molecules, combined with the interaction region indicator visualization, confirmed the absence of π-π stacking interactions in the Fe(TCPP)-MOF framework, thereby avoiding the aggregation-caused quenching effect. Furthermore, the permanent porosity and expansive surface area of Fe(TCPP)-MOF enhanced its interaction with oxygen. These ingenious structural features endowed Fe(TCPP)-MOF with a unique ability to generate a large amount of singlet oxygen under ultrasound activation. Meanwhile, the impetus of ultrasound also accelerated the rate of the Fenton reaction catalyzed by iron ions, significantly boosting the generation of hydroxyl radicals. Benefiting from the dual amplification of ROS, Fe(TCPP)-MOF could efficiently induce tumor cells pyroptosis under ultrasound stimulation, thereby intensifying the potency of cancer immunotherapy.

GSDMD-mediated pyroptosis: molecular mechanisms, diseases and therapeutic targets

Pyroptosis is a regulated form of inflammatory cell death in which Gasdermin D (GSDMD) plays a central role as the key effector molecule. GSDMD-mediated pyroptosis is characterized by complex biological features and considerable heterogeneity in its expression, mechanisms, and functional outcomes across various tissues, cell types, and pathological microenvironments. This heterogeneity is particularly pronounced in inflammation-related diseases and tumors. In the context of inflammatory diseases, GSDMD expression is typically upregulated, and its activation in macrophages, neutrophils, T cells, epithelial cells, and mitochondria triggers both pyroptotic and non-pyroptotic pathways, leading to the release of pro-inflammatory cytokines and exacerbation of tissue damage. However, under certain conditions, GSDMD-mediated pyroptosis may also serve a protective immune function. The expression of GSDMD in tumors is regulated in a more complex manner, where it can either promote immune evasion or, in some instances, induce tumor cell death. As our understanding of GSDMD's role continues to progress, there have been advancements in the development of inhibitors targeting GSDMD-mediated pyroptosis; however, these therapeutic interventions remain in the preclinical phase. This review systematically examines the cellular and molecular complexities of GSDMD-mediated pyroptosis, with a particular emphasis on its roles in inflammation-related diseases and cancer. Furthermore, it underscores the substantial therapeutic potential of GSDMD as a target for precision medicine, highlighting its promising clinical applications.

Nanomaterials evoke pyroptosis boosting cancer immunotherapy

Cancer immunotherapy is currently a very promising therapeutic strategy for treating tumors. However, its effectiveness is restricted by insufficient antigenicity and an immunosuppressive tumor microenvironment (ITME). Pyroptosis, a unique form of programmed cell death (PCD), causes cells to swell and rupture, releasing pro-inflammatory factors that can enhance immunogenicity and remodel the ITME. Nanomaterials, with their distinct advantages and different techniques, are increasingly popular, and nanomaterial-based delivery systems demonstrate significant potential to potentiate, enable, and augment pyroptosis. This review summarizes and discusses the emerging field of nanomaterials-induced pyroptosis, focusing on the mechanisms of nanomaterials-induced pyroptosis pathways and strategies to activate or enhance specific pyroptosis. Additionally, we provide perspectives on the development of this field, aiming to accelerate its further clinical transition.

Antimony Component Schottky Nanoheterojunctions as Ultrasound-Heightened Pyroptosis Initiators for Sonocatalytic Immunotherapy

Pyroptosis, an inflammatory modality of programmed cell death associated with the immune response, can be initiated by bioactive ions and reactive oxygen species (ROS). However, bioactive ion-induced pyroptosis lacks specificity, and further exploration of other ions that can induce pyroptosis in cancer cells is needed. Sonocatalytic therapy (SCT) holds promise due to its exceptional penetration depth; however, the rapid recombination of electron-hole (e--h+) pairs and the complex tumor microenvironment (TME) impede its broader application. Herein, we discovered that antimony (Sb)-based nanomaterials induced pyroptosis in cancer cells. Therefore, Schottky heterojunctions containing Sb component (Sb2Se3@Pt) were effectively designed and constructed via in situ growth of platinum (Pt) nanoparticles (NPs) on Sb2Se3 semiconductor with narrow band gaps, which were utilized as US-heightened pyroptosis initiators to induce highly effective pyroptosis in cancer cells to boost SCT-immunotherapy. Under US irradiation, excited electrons were transferred from Sb2Se3 nanorods (NRs) to the co-catalyst Pt via Schottky junctions, and band bending effectively prevented electron backflow and achieved efficient ROS generation. Moreover, the pores oxidized and depleted the overexpressed GSH in the TME, potentially amplifying ROS generation. The biological effects of the Sb2Se3@Pt nanoheterojunction itself combined with the sonocatalytic amplification of oxidative stress significantly induced Caspase-1/GSDMD-dependent pyroptosis in cancer cells. Therefore, SCT treatment with Sb2Se3@Pt not only effectively restrained tumor proliferation but also induced potent immune memory responses and suppressed tumor recurrence. Furthermore, the integration of this innovative strategy with immune checkpoint blockade (ICB) treatment elicited a systemic immune response, effectively augmenting therapeutic effects and impeding the growth of abscopal tumors. Overall, this study provides further opportunities to explore pyroptosis-mediated SCT-immunotherapy.

Progress in application of nanomedicines for enhancing cancer sono-immunotherapy

Cancer immunotherapy has significant potential as a cancer treatment since it boosts the immune system and prevents immune escape to get rid of or fight cancers. However, its clinical applicability is still limited because of the low response rate and immune-related side effects. Recently ultrasound has been shown to alter the tumor immune microenvironment, enhance the effectiveness of other antitumor therapies, and cause tumors to become more sensitive to immunotherapy, thus providing new insights into cancer treatment. Nanomedicines are also anticipated to have a positive impact on improving the immunological effects and enhancing ultrasound effect for cancer therapy. Therefore, designing effective nanomedicines enhanced ultrasound effect for augmenting sono-immunotherapy has been a pivot on anticancer therapy. In this review, the immunological impacts of various ultrasound therapeutic modalities, ultrasound parameters, and their underlying mechanisms are discussed. Moreover, we highlight the recent progress of nanomedicines synergistically enhancing sono-immunotherapy. Finally, we put forward opportunities and challenges on sono-immunotherapy.

Bacteria-Mediated Tumor-Targeting Delivery of Multienzyme-Mimicking Covalent Organic Frameworks Promoting Pyroptosis for Combinatorial Sono-Catalytic Immunotherapy

Pyroptosis, an inflammatory cell death, has attracted great attention for potentiating a strong immune response against tumor cells. However, developing powerful pyroptosis inducers and then activating specific pyroptosis still remains challenging. Herein, a PEG-CuP-COF@∆St nanosystem is rationally designed, consisting of PEG-CuP-COF nanozyme pyroptosis inducers and tumor-targeting bacteria of the Salmonella Typhimurium strain VNP20009 (ΔSt), with an affinity for the tumor hypoxic microenvironment. The PEG-CuP-COF nanozymes possessed excellent sonodynamic performance and multienzyme-mimicking activities to generate reactive oxygen species (ROS) and then induce potent pyroptosis. The superoxide dismutase- and peroxidase-mimicking activities of PEG-CuP-COF catalytically produced hydrogen peroxide (H2O2) and hydroxyl radicals (•OH) which have important value in triggering acute inflammatory responses and pyroptosis. Moreover, PEG-CuP-COF showed outstanding glutathione peroxidase-mimicking activities, impairing the antioxidant defense in tumor cells and enhancing sonodynamic efficiency by making them more vulnerable to ROS-induced damage. During in vivo studies, PEG-CuP-COF@∆St nanosystem with its self-driven property exhibited impressive tumor-targeting capability and activated Caspase-3/gasdermin E-dependent pyroptosis to inhibit tumor growth. More importantly, it induced a powerful immune memory effect to prevent bone metastasis. In summary, this study introduces an innovative approach for combinatorial sono-catalytic immunotherapy using bacteria-mediated tumor-targeting delivery of nanozymes as specific pyroptosis inducers.

Carbon dot-based nanomaterials with enzyme-like activity for fluorescence imaging and potential combination with therapy of cancer

Carbon dot-based nanomaterials (o-CDs@Mn) were fabricated by assembling fluorescent o-CDs with enzyme-like activity and Mn nanoparticles with photothermal properties for realizing fluorescence imaging and combined therapy of cancer. Due to the inherent optical properties of o-CDs, o-CDs@Mn can be effectively used for bioimaging. In addition, o-CDs@Mn possess peroxidase-like (POD-like) and glutathione (GSH) degradation capabilities, which can effectively deplete excessive H2O2 and GSH in the tumor microenvironment (TME), generating ·OH and reduced GSSH for regulating the TME and triggering ROS-mediated apoptosis in cancer cells. More importantly, it is synergistically supplemented with fluorescence imaging and photothermal therapy (PTT), which realizes the integration of monitoring and combined treatment, providing a promising potential pathway for accurate and efficient cancer treatment.

Tunable Structured 2D Nanobiocatalysts: Synthesis, Catalytic Properties and New Horizons in Biomedical Applications

2D materials have offered essential contributions to boosting biocatalytic efficiency in diverse biomedical applications due to the intrinsic enzyme-mimetic activity and massive specific surface area for loading metal catalytic centers. Since the difficulty of high-quality synthesis, the varied structure, and the tough choice of efficient surface loading sites with catalytic properties, the artificial building of 2D nanobiocatalysts still faces great challenges. Here, in this review, a timely and comprehensive summarization of the latest progress and future trends in the design and biotherapeutic applications of 2D nanobiocatalysts is provided, which is essential for their development. First, an overview of the synthesis-structure-fundamentals and structure-property relationships of 2D nanobiocatalysts, both metal-free and metal-based is provided. After that, the effective design of the active sites of nanobiocatalysts is discussed. Then, the progress of their applied research in recent years, including biomedical analysis, biomedical therapeutics, pharmacokinetics, and toxicology is systematically highlighted. Finally, future research directions of 2D nanobiocatalysts are prospected. Overall, this review to provide cutting-edge and multidisciplinary guidance for accelerating future developments and biomedical applications of 2D nanobiocatalysts is expected.

Enhanced pyroptosis induction with pore-forming gene delivery for osteosarcoma microenvironment reshaping

Osteosarcoma is the most common malignant bone tumor without efficient management for improving 5-year event-free survival. Immunotherapy is also limited due to its highly immunosuppressive tumor microenvironment (TME). Pore-forming gasdermins (GSDMs)-mediated pyroptosis has gained increasing concern in reshaping TME, however, the expressions and relationships of GSDMs with osteosarcoma remain unclear. Herein, gasdermin E (GSDME) expression is found to be positively correlated with the prognosis and immune infiltration of osteosarcoma patients, and low GSDME expression was observed. A vector termed as LPAD contains abundant hydroxyl groups for hydrating layer formation was then prepared to deliver the GSDME gene to upregulate protein expression in osteosarcoma for efficient TME reshaping via enhanced pyroptosis induction. Atomistic molecular dynamics simulations analysis proved that the hydroxyl groups increased LPAD hydration abilities by enhancing coulombic interaction. The upregulated GSDME expression together with cleaved caspase-3 provided impressive pyroptosis induction. The pyroptosis further initiated proinflammatory cytokines release, increased immune cell infiltration, activated adaptive immune responses and create a favorable immunogenic hot TME. The study not only confirms the role of GSDME in the immune infiltration and prognosis of osteosarcoma, but also provides a promising strategy for the inhibition of osteosarcoma by pore-forming GSDME gene delivery induced enhanced pyroptosis to reshape the TME of osteosarcoma.

Layered Double Hydroxide-Based PdCux@LDH Alloy Nanozyme for a Singlet Oxygen-Boosted Sonodynamic Therapy

Redox nanozymes have demonstrated tremendous promise in disrupting cellular homeostasis toward cancer therapy, but a dysfunctional competition of diverse activities makes it normally restricted by the complex tumor microenvironment (TME). As palladium nanocrystals can achieve the precise regulation of the enzyme-like activity by regulating exposed crystal planes, noble metal nanoalloys can enhance the enzyme-like activity by promoting electron transfer and enhanced active sites. Herein, bimetallic nanoalloys with optimized enzymatic activity were intelligently designed via the interaction between the Pd and layered double hydroxide, denoted as PdCux@LDH. This PdCux@LDH is able to produce long-lived singlet oxygen (1O2) with high efficiency and selectivity for ultrasound-improved cancer therapy. In addition, this PdCux@LDH nanozyme demonstrated unique surface-dependent multienzyme-mimicking activities for catalyzing cascade reactions: oxidase (OXD)- and catalase (CAT)-mimicking activities. Interestingly, ultrasound (US) stimulation can further improve the dual-enzyme-mimicking activities and impart superior reactive oxygen species (ROS) generation activity, thereby further consuming nicotinamide adenine dinucleotide (NADH) to cause mitochondrial dysfunction, resulting in a highly efficient alloy nanozyme-mediated cancer therapy. This work opens a new research avenue to apply nanozymes for effective sonodynamic therapies (SDT).

Oxygen-Vacancy-Engineered W18 O49-x Nanobrush with a Suitable Band Structure for Highly Efficient Sonodynamic Therapy

With the rapid development of external minimally invasive or noninvasive therapeutic modalities, ultrasound-based sonodynamic therapy (SDT) is a new alternative for treating deep tumors. However, inadequate sonosensitizer efficiency and poor biosecurity limit clinical applications. In this study, we prepared an oxygen-vacancy-engineered W18 O49-x nanobrush with a band gap of 2.79 eV for highly efficient SDT using a simple solvothermal method. The suitable band structures of the W18 O49-x nanobrush endows it with the potential to simultaneously produce singlet oxygen (1 O2 ), superoxide anions (⋅O2 - ), and hydroxyl radicals (⋅OH) under ultrasound irradiation. Additionally, abundant oxygen vacancies that serve as further charge traps that inhibit electron-hole recombination are incidentally introduced through one-step thermal reduction. Collectively, the in vitro and in vivo results demonstrate that the oxygen-vacancy-engineered W18 O49-x nanobrush delivers highly efficient reactive oxygen species (ROS) for SDT in a very biosafe manner. Overall, this study provides a new avenue for discovering and designing inorganic nanosonosensitizers with enhanced therapeutic efficiencies for use in SDT.

Oxygen self-supplying small size magnetic nanoenzymes for synergistic photodynamic and catalytic therapy of breast cancer

In recent years, tumor catalytic therapy based on nanozymes has attracted widespread attention. However, its application is limited by the tumor hypoxic microenvironment (TME). In this study, we developed oxygen-supplying magnetic bead nanozymes that integrate hemoglobin and encapsulate the photosensitizer curcumin, demonstrating reactive oxygen species (ROS)-induced synergistic breast cancer therapy. Fe3O4 magnetic bead-mediated catalytic dynamic therapy (CDT) generates hydroxyl radicals (˙OH) through the Fenton reaction in the tumor microenvironment. The Hb-encapsulated Fe3O4 magnetic beads can be co-loaded with the photosensitizer/chemotherapeutic agent curcumin (cur), resulting in Fe3O4-Hb@cur. Under hypoxic conditions, oxygen molecules are released from Fe3O4-Hb@cur to overcome the TME hypoxia, resulting in comprehensive effects favoring anti-tumor responses. Upon near-infrared (NIR) irradiation, Fe3O4-Hb@cur activates the surrounding molecular oxygen to generate a certain amount of singlet oxygen (1O2), which is utilized for photodynamic therapy (PDT) in cancer treatment. Meanwhile, we validated that the O2 carried by Hb significantly enhances the intracellular ROS level, intensifying the catalytic therapy mediated by Fe3O4 magnetic beads and inflicting lethal damage to cancer cells, effectively inhibiting tumor growth. Therefore, significant in vivo synergistic therapeutic effects can be achieved through catalytic-photodynamic combination therapy.

Nanozymes With Osteochondral Regenerative Effects: An Overview of Mechanisms and Recent Applications

With the discovery of the intrinsic enzyme-like activity of metal oxides, nanozymes garner significant attention due to their superior characteristics, such as low cost, high stability, multi-enzyme activity, and facile preparation. Notably, in the field of biomedicine, nanozymes primarily focus on disease detection, antibacterial properties, antitumor effects, and treatment of inflammatory conditions. However, the potential for application in regenerative medicine, which primarily addresses wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment, is garnering interest as well. This review introduces nanozymes as an innovative strategy within the realm of bone regenerative medicine. The primary focus of this approach lies in the facilitation of osteochondral regeneration through the modulation of the pathological microenvironment. The catalytic mechanisms of four types of representative nanozymes are first discussed. The pathological microenvironment inhibiting osteochondral regeneration, followed by summarizing the therapy mechanism of nanozymes to osteochondral regeneration barriers is introduced. Further, the therapeutic potential of nanozymes for bone diseases is included. To improve the therapeutic efficiency of nanozymes and facilitate their clinical translation, future potential applications in osteochondral diseases are also discussed and some significant challenges addressed.

PdMo nanoflowers for endogenous/exogenous-stimulated nanocatalytic therapy

The clinical application of reactive oxygen species (ROS)-mediated tumor treatment has been critically limited by inefficient ROS generation. Herein, we rationally synthesized and constructed the three-dimensional PdMo nanoflowers through a one-pot solvothermal reduction method for elaborately regulated peroxidase-like enzymatic activity and glutathione peroxidase-like enzymatic activity, to promote oxidation ROS evolvement and antioxidation glutathione depletion for achieving intensive ROS-mediated tumor therapy. The three-dimensional superstructure composed of two-dimensional nanosheet subunits can solve the issues by avoiding the appearance of tightly stacked crystalline nanostructures. Significantly, Mo is chosen as a second metal to alloy with Pd because of its more chemical valence and negative ionization energy than Pd for improved electron transfer efficiencies and enhanced enzyme-like activities. In addition, the photothermal effect generated by PdMo nanoflowers could also enhance its enzymatic activities. Thus, this work provides a promising paradigm for achieving highly ROS-mediated tumor therapeutic efficacy by regulating the multi-enzymatic activities of Pd-based nanoalloys.

Advances in the two-dimensional layer materials for cancer diagnosis and treatment: unique advantages beyond the microsphere

In recent years, two-dimensional (2D) layer materials have shown great potential in the field of cancer diagnosis and treatment due to their unique structural, electronic, and chemical properties. These non-spherical materials have attracted increasing attention around the world because of its widely used biological characteristics. The application of 2D layer materials like lamellar graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BPs) and so on have been developed for CT/MRI imaging, serum biosensing, drug targeting delivery, photothermal therapy, and photodynamic therapy. These unique applications for tumor are due to the multi-variable synthesis of 2D materials and the structural characteristics of good ductility different from microsphere. Based on the above considerations, the application of 2D materials in cancer is mainly carried out in the following three aspects: 1) In terms of accurate and rapid screening of tumor patients, we will focus on the enrichment of serum markers and sensitive signal transformation of 2D materials; 2) The progress of 2D nanomaterials in tumor MRI and CT imaging was described by comparing the performance of traditional contrast agents; 3) In the most important aspect, we will focus on the progress of 2D materials in the field of precision drug delivery and collaborative therapy, such as photothermal ablation, sonodynamic therapy, chemokinetic therapy, etc. In summary, this review provides a comprehensive overview of the advances in the application of 2D layer materials for tumor diagnosis and treatment, and emphasizes the performance difference between 2D materials and other types of nanoparticles (mainly spherical). With further research and development, these multifunctional layer materials hold great promise in the prospects, and challenges of 2D materials development are discussed.