"Electron Transport Chain Interference" Strategy of Amplified Mild-Photothermal Therapy and Defect-Engineered Multi-Enzymatic Activities for Synergistic Tumor-Personalized Suppression

A multifunctional cascade enzyme system for enhanced starvation/chemodynamic combination therapy against hypoxic tumors

Starvation therapy has shown promise as a cancer treatment, but its efficacy is often limited when used alone. In this work, a multifunctional nanoscale cascade enzyme system, named CaCO3@MnO2-NH2@GOx@PVP (CMGP), was fabricated for enhanced starvation/chemodynamic combination cancer therapy. CMGP is composed of CaCO3 nanoparticles wrapped in a MnO2 shell, with glucose oxidase (GOx) adsorbed and modified with polyvinylpyrrolidone (PVP). MnO2 decomposes H2O2 in cancer cells into O2, which enhances the efficiency of GOx-mediated starvation therapy. CaCO3 can be decomposed in the acidic cancer cell environment, causing Ca2+ overload in cancer cells and inhibiting mitochondrial metabolism. This synergizes with GOx to achieve more efficient starvation therapy. Additionally, the H2O2 and gluconic acid produced during glucose consumption by GOx are utilized by MnO2 with catalase-like activity to enhance O2 production and Mn2+ release. This process accelerates glucose consumption, reactive oxygen species (ROS) generation, and CaCO3 decomposition, promoting the Ca2+ release. CMGP can alleviate tumor hypoxia by cycling the enzymatic cascade reaction, which increases enzyme activity and combines with Ca2+ overload to achieve enhanced combined starvation/chemodynamic therapy. In vitro and in vivo studies demonstrate that CMGP has effective anticancer abilities and good biosafety. It represents a new strategy with great potential for combined cancer therapy.

MOF-Derived Oxygen-Deficient Titania-Mediated Photodynamic/Photothermal-Enhanced Immunotherapy for Tumor Treatment

Immunotherapy has emerged as a revolutionizing therapeutic modality for cancer. However, its efficacy has been largely limited by a weak immune response and an immunosuppressive tumor microenvironment. Herein, we report a metal-organic framework (MOF)-derived titanium oxide nanoparticle (MCTx NP) as an immune booster that can greatly improve the immunotherapy efficacy by inducing "immunogenic cell death" (ICD) and remodeling the tumor microenvironment. The NPs, inheriting the characteristic structure of MIL-125 and enriched with oxygen vacancies (OVs), demonstrate both high photothermal conversion efficiency and a reactive oxygen species (ROS) generation yield upon near-infrared (NIR) activation. Moreover, the NPs can release O2 and reduce glutathione (GSH) in the tumor environment, showcasing their potential to reverse the immunosuppressive microenvironment. In vitro/vivo results demonstrate that MCTx NPs directly kill tumor cells and effectively eliminate primary tumors by exerting dual photodynamic/photothermal therapy under a single NIR irritation. At the same time, MCTx NPs augment the PD-L1 blockade efficacy by potently inducing ICDs and reversing the immunosuppressive tumor microenvironment, including promoting dendritic cell (DC) maturation, decreasing regulatory T cells (Tregs)' infiltration, and increasing cytotoxic T lymphocytes (CTLs) and helper T cells (Ths), resulting in effective distant tumor suppression. This work highlights MCTx NP-mediated photodynamic- and photothermal-enhanced immunotherapy as an effective strategy for tumor treatment.

Potentiating dual-directional immunometabolic regulation with nanomedicine to enhance anti-tumor immunotherapy following incomplete photothermal ablation

Photothermal therapy (PTT) is a promising cancer treatment method due to its ability to induce tumor-specific T cell responses and enhance therapeutic outcomes. However, incomplete PTT can leave residual tumors that often lead to new metastases and decreased patient survival in clinical scenarios. This is primarily due to the release of ATP, a damage-associated molecular pattern that quickly transforms into the immunosuppressive metabolite adenosine by CD39, prevalent in the tumor microenvironment, thus promoting tumor immune evasion. This study presents a photothermal nanomedicine fabricated by electrostatic adsorption among the Fe-doped polydiaminopyridine (Fe-PDAP), indocyanine green (ICG), and CD39 inhibitor sodium polyoxotungstate (POM-1). The constructed Fe-PDAP@ICG@POM-1 (FIP) can induce tumor PTT and immunogenic cell death when exposed to a near-infrared laser. Significantly, it can inhibit the ATP-adenosine pathway by dual-directional immunometabolic regulation, resulting in increased ATP levels and decreased adenosine synthesis, which ultimately reverses the immunosuppressive microenvironment and increases the susceptibility of immune checkpoint blockade (aPD-1) therapy. With the aid of aPD-1, the dual-directional immunometabolic regulation strategy mediated by FIP can effectively suppress/eradicate primary and distant tumors and evoke long-term solid immunological memory. This study presents an immunometabolic control strategy to offer a salvage option for treating residual tumors following incomplete PTT.

Iron-Based Metal-Organic Frameworks as Multiple Cascade Synergistic Therapeutic Effect Nano-Drug Delivery Systems for Effective Tumor Elimination

Efforts have been made to improve the therapeutic efficiency of tumor treatments, and metal-organic frameworks (MOFs) have shown excellent potential in tumor therapy. Monotherapy for the treatment of tumors has limited effects due to the limitation of response conditions and inevitable multidrug resistance, which seriously affect the clinical therapeutic effect. In this study, we chose to construct a multiple cascade synergistic tumor drug delivery system MIL-101(Fe)-DOX-TCPP-MnO2@PDA-Ag (MDTM@P-Ag) using MOFs as drug carriers. Under near-infrared (NIR) laser irradiation, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Ag NPs loaded on MDTM@P-Ag can be activated to generate cytotoxic reactive oxygen species (ROS) and achieve photothermal conversion, thus effectively inducing the apoptosis of tumor cells and achieving a combined photodynamic/photothermal therapy. Once released at the tumor site, manganese dioxide (MnO2) can catalyze the decomposition of hydrogen peroxide (H2O2) in the acidic microenvironment of the tumor to generate oxygen (O2) and alleviate the hypoxic environment of the tumor. Fe3+/Mn2+ will mediate a Fenton/Fenton-like reaction to generate cytotoxic hydroxyl radicals (·OH), while depleting the high concentration of glutathione (GSH) in the tumor, thus enhancing the chemodynamic therapeutic effect. The successful preparation of the tumor drug delivery system and its good synergistic chemodynamic/photodynamic/photothermal therapeutic effect in tumor treatment can be demonstrated by the experimental results of material characterization, performance testing and in vitro experiments.

Wintersweet-like Nanohybrids of Titanium-doped Cerium Vanadate Loaded with Polypyrrole for Tumor Theranostic

Compromises between enhanced on-targeting reactivity and precise real-time monitoring in the tumor microenvironment (TME) are the main roadblocks for catalytic cancer therapy. The hallmark of a high level of hydrogen peroxide (H2O2) and acidic extracellular environment of the hypoxia solid tumor can underpin therapeutic and tracking performance. Herein, this work provides an activatable wintersweet-like nanohybrid consisting of titanium (Ti) doped cerium vanadate nanorods with the modification of polypyrrole (PPy) nanoparticles (CeVO4-Ti@PPy) for combinatorial therapies of breast carcinoma. The Ti dopants in the size-controllable CeVO4 nanorods lower the energy barrier (0.5 eV) of the rate-determining steps and elaborate peroxidase-like (POD-like) activities to improve the generation of toxic hydroxyl radical (·OH) according to the density functional theory (DFT) calculation. The multiple enzyme-like activities, including the intrinsic glutathione peroxidase (GPx) and catalase (CAT), achieve a record-high therapeutic efficiency. Coupling this oxidative stress with the photothermal effects of PPy enables enhanced catalytic tumor necrosis. The exterior PPy heterogeneous structure can be further doped with protons in the local acidic environment to intensify photoacoustic signals, allowing the non-invasive accurate tracking of tumors. The theranostic performance displayed negligible attenuated signals in near-infrared (NIR) windows. This organic-inorganic nanohybrid with a heterogeneous structure provides the potential to improve the overall outcomes of catalytic therapy.

Sulfated Chitosan-Modified CuS Nanocluster: A Versatile Nanoformulation for Simultaneous Antibacterial and Bone Regenerative Therapy in Periodontitis

Periodontitis, a prevalent chronic inflammatory disease worldwide, is triggered by periodontopathogenic bacteria, resulting in the progressive destruction of periodontal tissue, particularly the alveolar bone. To effectively address periodontitis, this study proposed a nanoformulation known as CuS@MSN-SCS. This formulation involves coating citrate-grafted copper sulfide (CuS) nanoparticles with mesoporous silica (MSNs), followed by surface modification using amino groups and sulfated chitosan (SCS) through electrostatic interactions. The objective of this formulation is to achieve efficient bacteria removal by inducing ROS signaling pathways mediated by Cu2+ ions. Additionally, it aims to promote alveolar bone regeneration through Cu2+-induced pro-angiogenesis and SCS-mediated bone regeneration. As anticipated, by regulating the surface charges, the negatively charged CuS nanoparticles capped with sodium citrate were successfully coated with MSNs, and the subsequent introduction of amine groups using (3-aminopropyl)triethoxysilane was followed by the incorporation of SCS through electrostatic interactions, resulting in the formation of CuS@MSN-SCS. The developed nanoformulation was verified to not only significantly exacerbate the oxidative stress of Fusobacterium nucleatum, thereby suppressing bacteria growth and biofilm formation in vitro, but also effectively alleviate the inflammatory response and promote alveolar bone regeneration without evident biotoxicity in an in vivo rat periodontitis model. These findings contribute to the therapeutic effect on periodontitis. Overall, this study successfully developed a nanoformulation for combating bacteria and facilitating alveolar bone regeneration, demonstrating the promising potential for clinical treatment of periodontitis.

Self-Regenerating Photothermal Agents for Tandem Photothermal and Thermodynamic Tumor Therapy

Small molecule-based photothermal agents (PTAs) hold promising future for photothermal therapy; however, unexpected inactivation exerts negative impacts on their application clinically. Herein, a self-regenerating PTA strategy is proposed by integrating 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+) with a thermodynamic agent (TDA) 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPH). Under NIR laser, the photothermal effect of ABTS•+ accelerates the production of alkyl radicals by AIPH, which activates the regeneration of ABTS•+, thus creating a continuous positive feedback loop between photothermal and thermodynamic effects. The combination of ABTS•+ regeneration and alkyl radical production leads to the tandem photothermal and thermodynamic tumor therapy. In vitro and in vivo experiments confirm that the synergistic action of thermal ablation, radical damage, and oxidative stress effectively realizes tumor suppression. This work offers a promising approach to address the unwanted inactivation of PTAs and provides valuable insights for optimizing combination therapy.

An ATPase-Mimicking MXene nanozyme pharmacologically breaks the ironclad defense system for ferroptosis cancer therapy

Anticancer nanomedicines used for ferroptosis therapy generally rely on the direct delivery of Fenton catalysts to drive lipid peroxidation in cancer cells. However, the therapeutic efficacy is limited by the ferroptosis resistance caused by the intracellular anti-ferroptotic signals. Herein, we report the intrinsic ATPase-mimicking activity of a vanadium carbide MXene nanozyme (PVCMs) to pharmacologically modulate the nuclear factor erythroid 2-related factor 2 (Nrf2) program, which is the master anti-ferroptotic mediator in the ironclad defense system in triple-negative breast cancer (TNBC) cells. The PVCMs perform high ATPase-like activity that can effectively and selectively catalyze the dephosphorylation of ATP to generate ADP. Through a cascade mechanism initiated by falling energy status, PVCMs can powerfully hinder the Nrf2 program to selectively drive ferroptosis in TNBC cells in response to PVCMs-induced glutathione depletion. This study provides a paradigm for the use of pharmacologically active nanozymes to moderate specific cellular signals and elicit desirable pharmacological activities for therapeutic applications.

Progress and Challenges in Tumor Ferroptosis Treatment Strategies: A Comprehensive Review of Metal Complexes and Nanomedicine

Ferroptosis is a new form of regulated cell death featuring iron-dependent lipid peroxides accumulation to kill tumor cells. A growing body of evidence has shown the potential of ferroptosis-based cancer therapy in eradicating refractory malignancies that are resistant to apoptosis-based conventional therapies. In recent years, studies have reported a number of ferroptosis inducers that can increase the vulnerability of tumor cells to ferroptosis by regulating ferroptosis-related signaling pathways. Encouraged by the rapid development of ferroptosis-driven cancer therapies, interdisciplinary fields that combine ferroptosis, pharmaceutical chemistry, and nanotechnology are focused. First, the prerequisites and metabolic pathways for ferroptosis are briefly introduced. Then, in detail emerging ferroptosis inducers designed to boost ferroptosis-induced tumor therapy, including metal complexes, metal-based nanoparticles, and metal-free nanoparticles are summarized. Subsequently, the application of synergistic strategies that combine ferroptosis with apoptosis and other regulated cell death for cancer therapy, with emphasis on the use of both cuproptosis and ferroptosis to induce redox dysregulation in tumor and intracellular bimetallic copper/iron metabolism disorders during tumor treatment is discussed. Finally, challenges associated with clinical translation and potential future directions for potentiating cancer ferroptosis therapies are highlighted.

Engineering Phage Nanocarriers Integrated with Bio-Intelligent Plasmids for Personalized and Tunable Enzyme Delivery to Enhance Chemodynamic Therapy

Customizable and number-tunable enzyme delivery nanocarriers will be useful in tumor therapy. Herein, a phage vehicle, T4-Lox-DNA-Fe (TLDF), which adeptly modulates enzyme numbers using phage display technology to remodel the tumor microenvironment (TME) is presented. Regarding the demand for lactic acid in tumors, each phage is engineered to display 720 lactate oxidase (Lox), contributing to the depletion of lactic acid to restructure the tumor's energy metabolism. The phage vehicle incorporated dextran iron (Fe) with Fenton reaction capabilities. H2O2 is generated through the Lox catalytic reaction, amplifying the H2O2 supply for dextran iron-based chemodynamic therapy (CDT). Drawing inspiration from the erythropoietin (EPO) biosynthetic process, an EPO enhancer is constructed to impart the EPO-Keap1 plasmid (DNA) with tumor hypoxia-activated functionality, disrupting the redox homeostasis of the TME. Lox consumes local oxygen, and positive feedback between the Lox and the plasmid promotes the expression of kelch ECH Associated Protein 1 (Keap1). Consequently, the downregulation of the antioxidant transcription factor Nrf2, in synergy with CDT, amplifies the oxidative killing effect, leading to tumor suppression of up to 78%. This study seamlessly integrates adaptable T4 phage vehicles with bio-intelligent plasmids, presenting a promising approach for tumor therapy.

Single-Atom Cu Nanozyme-Loaded Bone Scaffolds for Ferroptosis-Synergized Mild Photothermal Therapy in Osteosarcoma Treatment

The rapid multiplication of residual tumor cells and poor reconstruction quality of new bone are considered the major challenges in the postoperative treatment of osteosarcoma. It is a promising candidate for composite bone scaffold which combines photothermal therapy (PTT) and bone regeneration induction for the local treatment of osteosarcoma. However, it is inevitable to damage the normal tissues around the tumor due to the hyperthermia of PTT, while mild heat therapy shows a limited effect on antitumor treatment as the damage can be easily repaired by stress-induced heat shock proteins (HSP). This study reports a new type of single-atom Cu nanozyme-loaded bone scaffolds, which exhibit exceptional photothermal conversion properties as well as peroxidase and glutathione oxidase mimicking activities in vitro experiments. This leads to lipid peroxidation (LPO) and reactive oxygen species (ROS) upregulation, ultimately causing ferroptosis. The accumulation of LPO and ROS also contributes to HSP70 inactivation, maximizing PTT efficiency against tumors at an appropriate therapeutic temperature and minimizing the damage to surrounding normal tissues. Further, the bone scaffold promotes bone regeneration via a continuous release of bioactive ions (Ca2+, P5+, Si4+, and Cu2+). The results of in vivo experiments reveal that scaffolds inhibit tumor growth and promote bone repair.

A Versatile Nanozyme-Based NADH Circulating Oxidation Reactor for Tumor Therapy through Triple Cellular Metabolism Disruption

Nanozyme-based metabolic regulation triggered by tumor-specific endogenous stimuli has emerged as a promising therapeutic strategy for tumors. The current efficacy, however, is constrained by the limited concentration of endogenous substrates and the metabolic plasticity of tumors. Consequently, the implementation of efficient metabolic regulation in tumor therapy is urgently needed. Herein, a versatile nanozyme-based nicotinamide adenine dinucleotide (NADH) circulating oxidation nanoreactor is reported. First, the synthesized cobalt-doped hollow carbon spheres (Co-HCS) possess NADH oxidase (NOX)-mimicking activity for the NADH oxidation to disrupt oxidative phosphorylation (OXPHOS) pathway of tumor cells. Second, the substrate-cycle manner of Co-HCS can be used for NADH circulating oxidation to overcome the limitation of substrate deficiency. Finally, 2-Deoxy-D-glucose (2-DG) and 6-aminonicotinamide (6-AN) are introduced to block glycolysis and pentose phosphate pathway (PPP), thus creating a versatile nanozyme-based NADH circulating oxidation nanoreactor (Co-HCS/D/A) for tumor therapy through triple cellular metabolism disruption. In vitro and in vivo results demonstrate that the designed nanoreactor not only enhances the catalytic efficiency but also disrupts the tumor metabolic homeostasis, leading to efficient therapy outcome. This study develops a novel NADH circulating oxidation nanoreactor for tumor therapy through triple cellular metabolism disruption, which addresses the limitations of current nanozyme-based metabolism regulation for tumor therapy.

Piezoelectric Catalysis Induces Tumor Cell Senescence to Boost Chemo-Immunotherapy

Cellular senescence, a vulnerable state of growth arrest, has been regarded as a potential strategy to weaken the resistance of tumor cells, leading to dramatic improvements in treatment efficacy. However, a selective and efficient strategy for inducing local tumor cellular senescence has not yet been reported. Herein, piezoelectric catalysis is utilized to reduce intracellular NAD+ to NADH for local tumor cell senescence for the first time. In detail, a biocompatible nanomedicine (BTO/Rh-D@M) is constructed by wrapping the piezoelectric BaTiO3/(Cp*RhCl2)2 (BTO/Rh) and doxorubicin (DOX) in the homologous cytomembrane with tumor target. After tumors are stimulated by ultrasound, negative and positive charges are generated on the BTO/Rh by piezoelectric catalysis, which reduce the intracellular NAD+ to NADH for cellular senescence and oxidize H2O to reactive oxygen species (ROS) for mitochondrial damage. Thus, the therapeutic efficacy of tumor immunogenic cell death-induced chemo-immunotherapy is boosted by combining cellular senescence, DOX, and ROS. The results indicate that 23.9% of the piezoelectric catalysis-treated tumor cells senesced, and solid tumors in mice disappeared completely after therapy. Collectively, this study highlights a novel strategy to realize cellular senescence utilizing piezoelectric catalysis and the significance of inducing tumor cellular senescence to improve therapeutic efficacy.

Copper peroxide nanodot-decorated gold nanostar/silica nanorod Janus nanostructure with NIR-II photothermal and acid-triggered hydroxyl radical generation properties for the effective treatment of wound infections

Recently, bacterial infections have become a global crisis, greatly threatening the health of human beings. The development of a non-antibiotic biomaterial is recognized as an alternative way for the effective treatment of bacterial infections. In the present work, a multifunctional copper peroxide (CP) nanodot-decorated gold nanostar (GNS)/silica nanorod (SiNR) Janus nanostructure (GNS@CP/SiNR) with excellent antibacterial activity was reported. Due to the formation of the Janus nanostructure, GNS@CP/SiNR displayed strong plasmonic resonance absorbance in the near infrared (NIR)-II region that enabled the nanosystem to achieve mild photothermal therapy (MPTT). In acidic conditions, CP decorated on GNS@CP/SiNR dissociated rapidly by releasing Cu2+ and H2O2, which subsequently transformed to ˙OH via the Fenton-like reaction for chemodynamic therapy (CDT). As a result, GNS@CP/SiNR could effectively inhibit both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), and eradicate the associated bacterial biofilms by exerting the synergistic MPTT/CDT antibacterial effect. Moreover, GNS@CP/SiNR was also demonstrated to be effective in treating wound infections, as verified on the S. aureus-infected full thickness excision wound rat model. Our mechanism study revealed that the synergistic MPTT/CDT effect of GNS@CP/SiNR firstly caused bacterial membrane damage, followed by boosting intracellular ROS via the severe oxidative stress effect, which subsequently caused the depletion of intracellular GSH and DNA damage, finally leading to the death of bacteria.

Photothermal therapy: a novel potential treatment for prostate cancer

Prostate cancer (PCa) is a leading cause of cancer-related death in men, and most PCa patients treated with androgen deprivation therapy will progress to metastatic castration-resistant prostate cancer (mCRPC) due to the lack of efficient treatment. Recently, lots of research indicated that photothermal therapy (PTT) was a promising alternative that provided an accurate and efficient prostate cancer therapy. A photothermic agent (PTA) is a basic component of PPT and is divided into organic and inorganic PTAs. Besides, the combination of PTT and other therapies, such as photodynamic therapy (PDT), immunotherapy (IT), chemotherapy (CT), etc., provides an more efficient strategy for PCa therapy. Here, we introduce basic information about PTT and summarize the PTT treatment strategies for prostate cancer. Based on recent works, we think the combination of PPT and other therapies provides a novel possibility for PCa, especially CRPC clinical treatment.

Revealing the Optimization Route of Piezoelectric Sonosensitizers: From Mechanism to Engineering Methods

Piezoelectric catalysis is a novel catalytic technology that has developed rapidly in recent years and has attracted extensive interest among researchers in the field of tumor therapy for its acoustic-sensitizing properties. Nevertheless, researchers are still controversial about the key technical difficulties in the modulation of piezoelectric sonosensitizers for tumor therapy applications, which is undoubtedly a major obstacle to the performance modulation of piezoelectric sonosensitizers. Clarification of this challenge will be beneficial to the design and optimization of piezoelectric sonosensitizers in the future. Here, the authors start from the mechanism of piezoelectric catalysis and elaborate the mechanism and methods of defect engineering and phase engineering for the performance modulation of piezoelectric sonosensitizers based on the energy band theory. The combined therapeutic strategy of piezoelectric sonosensitizers with enzyme catalysis and immunotherapy is introduced. Finally, the challenges and prospects of piezoelectric sonosensitizers are highlighted. Hopefully, the explorations can guide researchers toward the optimization of piezoelectric sonosensitizers and can be applied in their own research.

Understanding the Novel Approach of Nanoferroptosis for Cancer Therapy

As a new form of regulated cell death, ferroptosis has unraveled the unsolicited theory of intrinsic apoptosis resistance by cancer cells. The molecular mechanism of ferroptosis depends on the induction of oxidative stress through excessive reactive oxygen species accumulation and glutathione depletion to damage the structural integrity of cells. Due to their high loading and structural tunability, nanocarriers can escort the delivery of ferro-therapeutics to the desired site through enhanced permeation or retention effect or by active targeting. This review shed light on the necessity of iron in cancer cell growth and the fascinating features of ferroptosis in regulating the cell cycle and metastasis. Additionally, we discussed the effect of ferroptosis-mediated therapy using nanoplatforms and their chemical basis in overcoming the barriers to cancer therapy.

PEGylated chitosan-coated nanophotosensitizers for effective cancer treatment by photothermal-photodynamic therapy combined with glutathione depletion

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has emerged as a promising strategy for cancer treatment. However, the poor photostability and photothermal conversion efficiency (PCE) of organic small-molecule photosensitizers, and the intracellular glutathione (GSH)-mediated singlet oxygen scavenging largely decline the antitumor efficacy of PTT and PDT. Herein, a versatile nanophotosensitizer (NPS) system is developed by ingenious incorporation of indocyanine green (ICG) into the PEGylated chitosan (PEG-CS)-coated polydopamine (PDA) nanoparticles via multiple π-π stacking, hydrophobic and electrostatic interactions. The PEG-CS-covered NPS showed prominent colloidal and photothermal stability as well as high PCE (ca 62.8 %). Meanwhile, the Michael addition between NPS and GSH can consume GSH, thus reducing the GSH-induced singlet oxygen scavenging. After being internalized by CT26 cells, the NPS under near-infrared laser irradiation produced massive singlet oxygen with the aid of thermo-enhanced intracellular GSH depletion to elicit mitochondrial damage and lipid peroxide formation, thus leading to ferroptosis and apoptosis. Importantly, the combined PTT and PDT delivered by NPS effectively inhibited CT26 tumor growth in vivo by light-activated intense hyperthermia and redox homeostasis disturbance. Overall, this work presents a new tactic of boosting antitumor potency of ICG-mediated phototherapy by PEG-CS-covered NPS.

Nanozymes with biomimetically designed properties for cancer treatment

Nanozymes, as a type of nanomaterials with enzymatic catalytic activity, have demonstrated tremendous potential in cancer treatment owing to their unique biomedical properties. However, the heterogeneity of tumors and the complex tumor microenvironment pose significant challenges to the in vivo catalytic efficacy of traditional nanozymes. Drawing inspiration from natural enzymes, scientists are now using biomimetic design to build nanozymes from the ground up. This approach aims to replicate the key characteristics of natural enzymes, including active structures, catalytic processes, and the ability to adapt to the tumor environment. This achieves selective optimization of nanozyme catalytic performance and therapeutic effects. This review takes a deep dive into the use of these biomimetically designed nanozymes in cancer treatment. It explores a range of biomimetic design strategies, from structural and process mimicry to advanced functional biomimicry. A significant focus is on tweaking the nanozyme structures to boost their catalytic performance, integrating them into complex enzyme networks similar to those in biological systems, and adjusting functions like altering tumor metabolism, reshaping the tumor environment, and enhancing drug delivery. The review also covers the applications of specially designed nanozymes in pan-cancer treatment, from catalytic therapy to improved traditional methods like chemotherapy, radiotherapy, and sonodynamic therapy, specifically analyzing the anti-tumor mechanisms of different therapeutic combination systems. Through rational design, these biomimetically designed nanozymes not only deepen the understanding of the regulatory mechanisms of nanozyme structure and performance but also adapt profoundly to tumor physiology, optimizing therapeutic effects and paving new pathways for innovative cancer treatment.

Glutathione Induced In situ Synthesis of Cu Single-Atom Nanozymes with Anaerobic Glycolysis Metabolism Interference for Boosting Cuproptosis

Single-atom nanozyme (SAzyme) has sparked increasing interest for catalytic antitumor treatment due to their more tunable and diverse active sites than natural metalloenzymes in complex physiological conditions. However, it is usually a hard task to precisely conduct catalysis at tumor sites after intravenous injection of those SAzyme with high reactivity. Moreover, the explorations of SAzymes in the anticancer application are still in its infancy and need to be developed. Herein, an in situ synthesis strategy for Cu SAzyme was constructed to convert adsorbed copper ions into isolated atoms anchored by oxygen atoms (Cu-O2/Cu-O4) via GSH-responsive deformability of supports. Our results suggest that the in situ activation process could further facilitate the dissociation of copper ions and the consumption of glutathione, thereby leading to copper deposition in cytoplasm and triggering cuproptosis. Moreover, the in situ synthesis of Cu SAzyme with peroxidase-like activity enabled the intracellular reactive oxygen species production, resulting in specifically disturbance of copper metabolism pathway. Meanwhile, the in situ exposed glucose transporter (GLUT) inhibitor phloretin (Ph) can block the glycose uptake to boost cuproptosis efficacy. Overall, this in situ activation strategy effectively diminished the off-target effects of SACs-induced catalytic therapies and introduced a promising treatment paradigm for advancing cuproptosis-associated therapies.

A Macrophage Membrane-Coated Cu-WO3-x-Hydro820 Nanoreactor for Treatment and Photoacoustic/Fluorescence Dual-Mode Imaging of Inflamed Liver Tissue

A disease-targeting nanoplatform that integrates imaging with therapeutic activity would facilitate early diagnosis, treatment, and therapeutic monitoring. To this end, a macrophage membrane-coated Cu-WO3-x-Hydro820 (CWHM) nanoreactor was prepared. This reactor was shown to target inflammatory tissues. The reactive oxygen species (ROS) such as H2O2 and ·OH in inflammatory tissues can react with Hydro820 in the reactor to form the NIR fluorophore IR820. This process allowed photoacoustic/fluorescence dual-mode imaging of H2O2 and ·OH, and it is expected to permit visual diagnosis of inflammatory diseases. The Cu-WO3-x nanoparticles within the nanoreactor shown catalase and superoxide enzyme mimetic activity, allowing the nanoreactor to catalyze the decomposition of H2O2 and ·O2- in inflammatory cells of hepatic tissues in a mouse model of liver injury, thus alleviating the oxidative stress of damaged liver tissue. This nanoreactor illustrates a new strategy for the diagnosis and treatment of hepatitis and inflammatory liver injury.

Multienzyme-Like Polyoxometalate-Based Single-Atom Enzymes for Cancer-Specific Therapy Through Acid-Triggered Nontoxicity-to-Toxicity Transition

Single-atom enzymes (SAzymes) exhibit great potential for chemodynamic therapy (CDT); while, general application is still challenged by their instability and unavoidable side effects during delivery. Herein, a manganese-based polyoxometalate single-atom enzyme (Mn-POM SAE) is first introduced into tumor-specific CDT, which exhibits tumor microenvironment (TME)-activated transition of nontoxicity-to-toxicity. Different from traditional POM materials, the aggregates of low-toxic Mn-POM SAE nanospheres are obtained at neutral conditions, facilitating efficient delivery and avoiding toxicity problems in normal tissues. Under acid TME conditions, these nanospheres are degraded into smaller units of toxic Mn(II)-PW11; thus, initiating cancer cell-specific therapy. The released active units of Mn(II)-PW11 exhibit excellent multienzyme-like activities (including peroxidase (POD)-like, oxidase (OXD)-like, catalase (CAT)-like, and glutathione peroxidase (Gpx)-like activities) for the synergistic cancer therapy due to the stabilized high valence Mn species (MnIII/MnIV). As demonstrated by both intracellular evaluations and in vivo experiments, ROS is generated to cause damage to lysosome membranes, further facilitating acidification and impaired autophagy to enhance cancer therapy. This study provides a detailed investigation on the acid-triggered releasing of active units and the electron transfer in multienzyme-mimic-like therapy, further enlarging the application of POMs from catalytical engineering into cancer therapy.

Microneedle-mediated nanomedicine to enhance therapeutic and diagnostic efficacy

Nanomedicine has been extensively explored for therapeutic and diagnostic applications in recent years, owing to its numerous advantages such as controlled release, targeted delivery, and efficient protection of encapsulated agents. Integration of microneedle technologies with nanomedicine has the potential to address current limitations in nanomedicine for drug delivery including relatively low therapeutic efficacy and poor patient compliance and enable theragnostic uses. In this Review, we first summarize representative types of nanomedicine and describe their broad applications. We then outline the current challenges faced by nanomedicine, with a focus on issues related to physical barriers, biological barriers, and patient compliance. Next, we provide an overview of microneedle systems, including their definition, manufacturing strategies, drug release mechanisms, and current advantages and challenges. We also discuss the use of microneedle-mediated nanomedicine systems for therapeutic and diagnostic applications. Finally, we provide a perspective on the current status and future prospects for microneedle-mediated nanomedicine for biomedical applications.

OXPHOS-targeted nanoparticles for boosting photodynamic therapy against hypoxia tumor

Hypoxia as an inherent feature in tumors is firmly associated with unsatisfactory clinical outcomes of photodynamic therapy (PDT) since the lack of oxygen leads to ineffective reactive oxygen species (ROS) productivity for tumor eradication. In this study, an oxidative phosphorylation (OXPHOS) targeting nanoplatform was fabricated to alleviate hypoxia and enhance the performance of PDT by encapsulating IR780 and OXPHOS inhibitor atovaquone (ATO) in triphenylphosphine (TPP) modified poly(ethylene glycol) methyl ether-block-poly(L-lactide-co-glycolide) (mPEG-PLGA) nanocarriers (TNPs/IA). ATO by interrupting the electron transfer in OXPHOS could suppress mitochondrial respiration of tumor cells, economising on oxygen for the generation of ROS. Benefiting from the mitochondrial targeting function of TPP, ATO was directly delivered to its site of action to obtain highlighted effect at a lower dosage. Furthermore, positioning the photosensitizer IR780 to mitochondria, a more vulnerable organelle to ROS, was a promising method to attenuate the spatiotemporal limitation of ROS caused by its short half-life and narrow diffusion radius. As a result, TNPs/IA exhibited accurate subcellular localization, lead to the collapse of ATP production by damaging mitochondrion and elicited significant antitumor efficacy via oxygen-augmented PDT in the HeLa subcutaneous xenograft model. Overall, TNPs/IA was a potential strategy in photodynamic eradication of tumors.

Engineering Nanozymes for Tumor Therapy via Ferroptosis Self-Amplification

Ferroptosis induction is an emerging strategy for tumor therapy. Reactive oxygen species (ROS) can induce ferroptosis but are easily consumed by overexpressed glutathione (GSH) in tumor cells. Therefore, achieving a large amount of ROS production in tumor cells without being consumed is key to efficiently inducing ferroptosis. In this study, a self-amplifying ferroptosis-inducing therapeutic agent, Pd@CeO2-Fe-Co-WZB117-DSPE-PEG-FA (PCDWD), is designed for tumor therapy. PCDWD exhibits excellent multi-enzyme activities due to the loading of Fe-Co dual atoms with abundant active sites, including peroxidase-like enzymes, catalase-like enzymes, and glutathione oxidases (GSHOx), which undergo catalytic reactions in the tumor microenvironment to produce ROS, thereby inducing ferroptosis. Furthermore, PCDWD can also deplete GSH in tumor cells, thus reducing the consumption of ROS by GSH and inhibiting the expression of GSH peroxidase 4. Moreover, the photothermal effect of PCDWD can not only directly kill tumor cells but also further enhance its own enzyme activities, consequently promoting ferroptosis in tumor cells. In addition, WZB117 can reduce the expression of heat shock protein 90 by inhibiting glucose transport, thereby reducing the thermal resistance of tumor cells and further improving the therapeutic effect. Finally, X-ray computed tomography imaging of PCDWD guides it to achieve efficient tumor therapy.

Prepared MW-Immunosensitizers Precisely Release NO to Downregulate HIF-1α Expression and Enhance Immunogenic Cell Death

Microwave thermotherapy (MWTT) has limited its application in the clinic due to its high rate of metastasis and recurrence after treatment. Nitric oxide (NO) is a gaseous molecule that can address the high metastasis and recurrence rates after MWTT by increasing thermal sensitivity, down-regulating the expression of hypoxia-inducible factor-1 (HIF-1), and inducing the immunogenic cell death (ICD). Therefore, GaMOF-Arg is designed, a gallium-based organic skeleton material derivative loaded with L-arginine (L-Arg), and coupled the mitochondria-targeting drug of triphenylphosphine (TPP) on its surface to obtain GaMOF-Arg-TPP (GAT) MW-immunosensitizers. When GAT MW-immunosensitizers are introduced into mice through the tail vein, reactive oxygen species (ROS) are generated and L-Arg is released under MW action. Then, L-Arg reacts with ROS to generate NO, which not only downregulates HIF-1 expression to improve tumor hypoxia exacerbated by MW, but also enhances immune responses by augment calreticulin (CRT) exposure, high mobility group box 1 (HMGB1) release, and T-cell proliferation to achieve prevention of tumor metastasis and recurrence. In addition, NO can induce mitochondria damage to increase their sensitivity to MWTT. This study provides a unique insight into the use of metal-organic framework MW-immunosensitizers to enhance tumor therapy and offers a new way to treat cancer efficiently.

Injectable Conductive Hydrogel with Self-Healing, Motion Monitoring, and Bacteria Theranostics for Bioelectronic Wound Dressing

Wounds at joints are difficult to treat and tend to recover more slowly due to the frequent motions. When using traditional hydrogel dressings, they are easy to crack and undergo bacterial infection, difficult to match and monitor the irregular wounds. Integrating multiple functions within a hydrogel dressing to achieve intelligent wound monitoring and healing remains a significant challenge. In this research, a multifunctional hydrogel is developed based on polysaccharide biopolymer, poly(vinyl alcohol), and hydroxylated graphene through dynamic borate ester bonding and supramolecular interaction. The prepared hydrogel not only exhibits rapid self-healing (within 60 s), injectable, conductive and motion monitoring properties, but also realizes in situ bacterial sensing and killing functions. It shows excellent bacterial sensitivity (within 15 min) and killing ability via the changes of electrical signals and photothermal therapy, avoiding the emergence of drug-resistant bacteria. In vivo experiments prove that the hydrogel can promote wound healing effectively. In addition, it displays great electromechanical performance to achieve real-time monitoring and prevent re-tearing of the wound at human joints. The injectable pH-responsive hydrogel with good biocompatibility demonstrates considerable potential as multifunctional bioelectronic dressing for the detection, treatment, management, and healing of infected joint wounds.

Spatiotemporal Synergism in Osteomyelitis Treatment with Photoactivated Core-Shell Zinc Oxide/Silver Sulfide Heterogeneous Nanoparticles

Osteomyelitis is primarily caused by bacterial infections, and treatment requires precise sequential therapy, including antibacterial therapy in the early stages and bone defect reconstruction in later stages. We aimed to synthesize core-shell-structured zinc oxide/silver sulfide heterogeneous nanoparticles (ZnO/Ag2S NPs) using wet chemical methods. Using density functional theory and ultraviolet photoelectron spectroscopy, we showed that the optimized band structure endowed ZnO/Ag2S NPs with photodynamic properties under near-infrared (NIR) irradiation. Moreover, ZnO/Ag2S NPs exhibited a distinguished and stable photothermal performance within the same wavelength range. With single-wavelength irradiation, ZnO/Ag2S NPs achieved a bifunctional antibacterial effect during the acute stage of osteomyelitis. Antibacterial action was confirmed through colony-forming unit (CFU) counting assays, scanning electronic microscopy (SEM) observations, live-dead staining, growth curves, and quantitative real-time polymerase chain reaction (qPCR) assays. The Ag2S coating on the NPs realized the sustained release of zinc ions, thereby controlling the zinc ion concentration. Alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, and qPCR assays confirmed that the ZnO/Ag2S NPs exhibited good osteogenic effects in vitro. These effects were verified in an in vivo mouse femur model during chronic stages using micro-computed tomography (micro-CT) and histological analysis. This study provides a novel biocompatible core-shell nanomaterial for the two-phase treatment of osteomyelitis, contributing to versatile nanotherapies for infections and inflammation.

Leveraging Radiation-triggered Metal Prodrug Activation Through Nanosurface Energy Transfer for Directed Radio-chemo-immunotherapy

Metal-based drugs currently dominate the field of chemotherapeutic agents; however, achieving the controlled activation of metal prodrugs remains a substantial challenge. Here, we propose a universal strategy for the radiation-triggered activation of metal prodrugs via nanosurface energy transfer (NSET). The core-shell nanoplatform (Ru-GNC) is composed of gold nanoclusters (GNC) and ruthenium (Ru)-containing organic-inorganic hybrid coatings. Upon X-ray irradiation, chemotherapeutic Ru (II) complexes were released in a controlled manner through a unique NSET process involving the transfer of photoelectron energy from the radiation-excited Ru-GNCs to the Ru-containing hybrid layer. In contrast to the traditional radiation-triggered activation of prodrugs, such an NSET-based system ensures that the reactive species in the tumor microenvironment are present in sufficient quantity and are not easily quenched. Additionally, ultrasmall Ru-GNCs preferably target mitochondria and profoundly disrupt the respiratory chain upon irradiation, leading to radiosensitization by generating abundant reactive oxygen species. Consequently, Ru-GNC-directed radiochemotherapy induces immunogenic cell death, resulting in significant therapeutic outcomes when combined with the programmed cell death-ligand 1 (PD-L1) checkpoint blockade. This NSET strategy represents a breakthrough in designing radiation-triggered nanoplatforms for metal-prodrug-mediated cancer treatment in an efficient and controllable manner.

Structure Engineered High Piezo-Photoelectronic Performance for Boosted Sono-Photodynamic Therapy

Sono-photodynamic therapy is hindered by the limited tissue penetration depth of the external light source and the quick recombination of electron-hole owing to the random movement of charge carriers. In this study, orthorhombic ZnSnO3 quantum dots (QDs) with piezo-photoelectronic effects are successfully encapsulated in hexagonal upconversion nanoparticles (UCNPs) using a one-pot thermal decomposition method to form an all-in-one watermelon-like structured sono-photosensitizer (ZnSnO3 @UCNPs). The excited near-infrared light has high penetration depth, and the watermelon-like structure allows for full contact between the UCNPs and ZnSnO3 QDs, achieving ultrahigh Förster resonance energy transfer efficiency of up to 80.30%. Upon ultrasonic and near-infrared laser co-activation, the high temperature and pressure generated lead to the deformation of the UCNPs, thereby driving the deformation of all ZnSnO3 QDs inside the UCNPs, forming many small internal electric fields similar to isotropic electric domains. This piezoelectric effect not only increases the internal electric field intensity of the entire material but also prevents random movement and rapid recombination of charge carriers, thereby achieving satisfactory piezocatalytic performance. By combining the photodynamic effect arising from the energy transfer from UCNPs to ZnSnO3 , synergistic efficacy is realized. This study proposes a novel strategy for designing highly efficient sono-photosensitizers through structural design.

Recent advances in metal-organic frameworks for stimuli-responsive drug delivery

After entering the human body, drugs for treating diseases, which are prone to delivery and release in an uncontrolled manner, are affected by various factors. Based on this, many researchers utilize various microenvironmental changes encountered during drug delivery to trigger drug release and have proposed stimuli-responsive drug delivery systems. In recent years, metal-organic frameworks (MOFs) have become promising stimuli-responsive agents to release the loaded therapeutic agents at the target site to achieve more precise drug delivery due to their high drug loading, excellent biocompatibility, and high stimuli-responsiveness. The MOF-based stimuli-responsive systems can respond to various stimuli under pathological conditions at the site of the lesion, releasing the loaded therapeutic agent in a controlled manner, and improving the accuracy and safety of drug delivery. Due to the changes in different physical and chemical factors in the pathological process of diseases, the construction of stimuli-responsive systems based on MOFs has become a new direction in drug delivery and controlled release. Based on the background of the rapidly increasing attention to MOFs applied in drug delivery, we aim to review various MOF-based stimuli-responsive drug delivery systems and their response mechanisms to various stimuli. In addition, the current challenges and future perspectives of MOF-based stimuli-responsive drug delivery systems are also discussed in this review.

Self-Destructive Copper Carriers Induce Pyroptosis and Cuproptosis for Efficient Tumor Immunotherapy Against Dormant and Recurrent Tumors

Activating the strong immune system is a key initiative to counteract dormant tumors and prevent recurrence. Herein, self-destructive and multienzymatically active copper-quinone-GOx nanoparticles (abbreviated as CQG NPs) have been designed to induce harmonious and balanced pyroptosis and cuproptosis using the "Tai Chi mindset" to awaken the immune response for suppressing dormant and recurrent tumors. This cleverly designed material can disrupt the antioxidant defense mechanism of tumor cells by inhibiting the nuclear factor-erythroid 2-related factor 2 (NRF2)-quinone oxidoreductase 1 (NQO1) signaling pathway. Furthermore, combined with its excellent multienzyme activity, it activates NOD-like receptor protein 3 (NLRP3)-mediated pyroptosis. Meanwhile, cuproptosis can be triggered by copper ions released from the self-destructive disintegration of CQG NPs and the sensitivity of cancer cells to cuproptosis is enhanced through the depletion of endogenous copper chelators via the Michael addition reaction between glutathione (GSH) and quinone ligand, oxygen production from catalase-like reaction, and starvation-induced glucose deficiency. More importantly, CQG NPs-induced pyroptosis and cuproptosis can promote immunosuppressive tumor microenvironment (TME) remodeling, enhance the infiltration of immune cells into the tumor, and activate robust systemic immunity. Collectively, this study provides a new strategy to resist tumor dormancy, prevent tumor recurrence, and improve the clinical prognosis of tumors.

Near-Infrared Light-Triggered Thermoresponsive Pyroptosis System for Synergistic Tumor Immunotherapy

Pyroptosis, as an inflammatory cell death, has been widely applied in tumor therapy, but its systemic adverse reactions caused by nonspecific activation still seriously hinder its application. Herein, a near-infrared (NIR) light-triggered thermoresponsive pyroptosis strategy is designed for on-demand initiation of pyroptosis and synergistic tumor immunotherapy. Specifically, glucose oxidase (GOx) loaded and heat-sensitive material p(OEOMA-co-MEMA) (PCM) modified mesoporous Pt nanoparticles (abbreviated as PCM Pt/GOx) are prepared as the mild-temperature triggered pyroptosis inducer. Pt nanoparticles can not only serve as nanozyme with catalase-like activity to promote GOx catalytic reaction, but also act as photothermal agent to achieve mild-temperature photothermal therapy (PTT) and thermoresponsive GOx release on-demand under the irradiation of NIR light, thereby activating and promoting pyroptosis. In vitro and in vivo experiments prove that NIR light-triggered thermoresponsive pyroptosis system exhibits excellent antitumor immunity activity as well as significantly inhibits tumor growth. The precise control of pyroptosis by NIR light as well as pyroptosis cooperated with mild-temperature PTT for synergistically attenuated tumor immunotherapy are reported for the first time. This work provides a new method to initiate pyroptosis on demand, which is of great significance for spatiotemporally controllable pyroptosis and immunotherapy.

In Situ Synthesis of Ru/TiO2- x @TiCN Ternary Heterojunctions for Enhanced Sonodynamic and Nanocatalytic Cancer Therapy

Albeit nanozymes-based tumor catalytic therapy (NCT) relies on endogenous chemical reactions that could achieve tumor microenvironment (TME)-specialized reactive oxygen species (ROS) production, the unsatisfactory catalytic activity of nanozymes accompanied by complex TME poses a barrier to the therapeutic effect of NCT. Herein, a one-step in situ synthesis strategy is reported to construct ternary Ru/TiO2- x @TiCN heterojunctions through oxidative conversion of TiCN nanosheets (NSs) to TiO2- x NSs and reductive deposition of Ru3+ to Ru nanoparticles. The narrow bandgap and existence of heterojunctions enhance the ultrasound-activated ROS generation of Ru/TiO2- x @TiCN because of the accelerated electron transfer and inhibits electron-hole pair recombination. The augmented ROS production efficiency is achieved by Ru/TiO2- x @TiCN with triple enzyme-like activities, which amplifies the ROS levels in a cascade manner through the catalytic decomposition of endogenous H2 O2 to relieve hypoxia and heterojunction-mediated NCT, as well as depletion of overexpressed glutathione. The satisfactory therapeutic effects of Ru/TiO2- x @TiCN heterojunctions are achieved through synergetic sonodynamic therapy and NCT, which achieve the complete elimination of tumors without recurrence. This strategy highlights the potential of in situ synthesis of semiconductor heterojunctions as enhanced sonosensitizers and nanozymes for efficient tumor therapy.

Hafnium (Hf)-Chelating Porphyrin-Decorated Gold Nanosensitizers for Enhanced Radio-Radiodynamic Therapy of Colon Carcinoma

X-ray-induced radiodynamic therapy (RDT) that can significantly reduce radiation dose with an improved anticancer effect has emerged as an attractive and promising therapeutic modality for tumors. However, it is highly significant to develop safe and efficient radiosensitizing agents for tumor radiation therapy. Herein, we present a smart nanotheranostic system FA-Au-CH that consists of gold nanoradiosensitizers, photosensitizer chlorin e6 (Ce6), and folic acid (FA) as a folate-receptor-targeting ligand for improved tumor specificity. FA-Au-CH nanoparticles have been demonstrated to be able to simultaneously serve as radiosensitizers and RDT agents for enhanced computed tomography (CT) imaging-guided radiotherapy (RT) of colon carcinoma, owing to the strong X-ray attenuation capability of high-Z elements Au and Hf, as well as the characteristics of Hf that can transfer radiation energy to Ce6 to generate ROS from Ce6 under X-ray irradiation. The integration of RT and RDT in this study demonstrates great efficacy and offers a promising therapeutic modality for the treatment of malignant tumors.

Developing Single-Atomic Manganese Nanozymes for Synergistic Mild Photothermal/Multienzymatic Therapy

Synergistic mild photothermal/nanozyme therapy with outstanding hyperthermia performance and excellent multienzyme properties is highly needed for osteosarcoma treatment. Herein, we have developed efficient single-atom nanozymes (SANs) consisting of Mn sites atomically dispersed on nitrogen-doped carbon nanosheets (denoted as Mn-SANs) for synergistic mild photothermal/multienzymatic therapy against osteosarcoma. Benefiting from their black N-doped carbon nanosheet matrices, Mn-SANs showed an excellent NIR-II-triggered photothermal effect. On the other hand, Mn-SANs with atomically dispersed Mn sites have outstanding multienzyme activities. Mn-SANs can catalyze endogenous H2O2 in osteosarcoma into O2 by catalase (CAT)-like activity, which can effectively ease osteosarcoma hypoxia and trigger the oxidase (OXD)-like catalysis that converts O2 to the cytotoxic superoxide anion radical (•O2-). At the same time, Mn-SANs can also mimic glutathione oxidase (GSHOx) to effectively consume the antioxidant glutathione (GSH) in osteosarcoma and inhibit intracellular glutathione peroxidase 4 (GPX4) expression. Such intratumoral •O2- production, GSH depletion, and GPX4 inactivation mediated by Mn-SANs can create a large accumulation of lipid peroxides (LPO) and •O2-, leading to oxidative stress and disrupting the redox homeostasis in osteosarcoma cells, which can ultimately induce osteosarcoma cell death. More importantly, heat shock proteins (HSPs) can be significantly destroyed via Mn-SAN-mediated plentiful LPO and •O2- generation, thus effectively impairing osteosarcoma cells resistant to mild photothermal therapy. Overall, through the cooperative effect of chemical processes (boosting •O2-, consuming GSH, and enhancing LPO) and biological processes (inactivating GPX4 and hindering HSPs), collaborative mild photothermal/multienzymatic therapy mediated by Mn-SANs is a promising strategy for efficient osteosarcoma treatment.

A Gene-Editable Palladium-Based Bioorthogonal Nanoplatform Facilitates Macrophage Phagocytosis for Tumor Therapy

Macrophage phagocytosis of tumor cells has emerged as an attractive strategy for tumor therapy. Nevertheless, immunosuppressive M2 macrophages in the tumor microenvironment and the high expression of anti-phagocytic signals from tumor cells impede therapeutic efficacy. To address these issues and improve the management of malignant tumors, in this study we developed a gene-editable palladium-based bioorthogonal nanoplatform, consisting of CRISPR/Cas9 gene editing system-linked Pd nanoclusters, and a hyaluronic acid surface layer (HBPdC). This HBPdC nanoplatform exhibited satisfactory tumor-targeting efficiency and triggered Fenton-like reactions in the tumor microenvironment to generate reactive oxygen species for chemodynamic therapy and macrophage M1 polarization, which directly eliminated tumor cells, and stimulated the antitumor response of macrophages. HBPdC could reprogram tumor cells through gene editing to reduce the expression of CD47 and adipocyte plasma membrane-associated protein, thereby promoting their recognition and phagocytosis by macrophages. Moreover, HBPdC induced the activation of sequestered prodrugs via bioorthogonal catalysis, enabling chemotherapy and thereby enhancing tumor cell death. Importantly, the Pd nanoclusters of HBPdC were sufficiently cleared through basic metabolic pathways, confirming their biocompatibility and biosafety. Therefore, by promoting macrophage phagocytosis, the HBPdC system developed herein represents a highly promising antitumor toolset for cancer therapy applications.

Trisulfide Bond-Mediated Molecular Phototheranostic Platform for "Activatable" NIR-II Imaging-Guided Enhanced Gas/Chemo-Hypothermal Photothermal Therapy

Tumor microenvironment (TME)-triggered phototheranostic platform offers a feasible strategy to improve cancer diagnosis accuracy and minimize treatment side effects. Developing a stable and biocompatible molecular phototheranostic platform for TME-activated second near-infrared (NIR-II) fluorescence imaging-guided multimodal cascade therapy is a promising strategy for creating desirable anticancer agents. Herein, a new NIR-II fluorescence imaging-guided activatable molecular phototheranostic platform (IR-FEP-RGD-S-S-S-Fc) is presented for actively targeted tumor imaging and hydrogen sulfide (H2 S) gas-enhanced chemodynamic-hypothermal photothermal combined therapy (CDT/HPTT). It is revealed for the first time that the coupling distance between IR-FE and ferrocene is proportional to the photoinduced electron transfer (PET), and the aqueous environment is favorable for PET generation. The part of Cyclic-RGDfK (cRGDfk) peptides can target the tumor and benefit the endocytosis of nanoparticles. The high-concentration glutathione (GSH) in the TME will separate the fluorescence molecule and ferrocene by the GSH-sensitive trisulfide bond, realizing light-up NIR-II fluorescence imaging and a cascade of trimodal synergistic CDT/HPTT/gas therapy (GT). In addition, the accumulation of hydroxyl radicals (•OH) and down-regulation of glutathione peroxidase 4 (GPX4) can produce excessive harmful lipid hydroperoxides, ultimately leading to ferroptosis.

Rationally Integrated Precise ER-Targeted and Oxygen-Compensated Photodynamic Immunostimulant for Immunogenicity-Boosted Tumor Therapy

Notwithstanding that immunotherapy has made eminent clinical breakthroughs, activating the immunogenicity and breaking the immunosuppressive tumor microenvironment (ITME) remains tempting yet challenging. Herein, a customized-designed immunostimulant is engineered for attenuating ITME and eliciting an immune response to address this challenge head-on. This immunostimulant is equipped with dual silica layers coated upconversion nanoparticles (UCNPs) as nanocarriers modified with endoplasmic reticulum (ER)-targeted molecular N-p-Tosylglycine, in which the dense silica for chlorin e6 (Ce6) and the glutathione (GSH)-responsive degradable silica for loading resveratrol (RES) - (UCSMRER ). On the one hand, this precise ER-targeted photodynamic therapy (PDT) can generate reactive oxygen species (ROS) in situ under the 980 nm laser irradiation, which not only induced severe cell death directly but also caused intense ER stress-based immunogenic cell death (ICD). On the other hand, tumor hypoxia aggravated by the PDT is alleviated by RES released on-demand, which reduced oxygen consumption by impairing the mitochondrial electron transport chain (ETC). This integrated precise ER-targeted and oxygen-compensated strategy maximized the PDT effect and potentiated ICD-associated immunotherapy, which availed to attenuate ITME, activate tumor immunogenicity, and further magnify the anti-tumor effect. This innovative concept about PDT and immunotherapy sheds light on cancer-related clinical application.

Catalyzing Generation and Stabilization of Oxygen Vacancies on CeO2-x Nanorods by Pt Nanoclusters as Nanozymes for Catalytic Therapy

Although CeO2 nanomaterials have been widely explored as nanozymes for catalytic therapy, they still suffer from relatively low activities. Herein, the catalyzing generation and stabilization of oxygen vacancies on CeO2 nanorods by Pt nanoclusters via H2 gas reduction under mild temperature (350 °C) to obtain Pt/CeO2- x , which can serve as a highly efficient nanozyme for catalytic cancer therapy, is reported. The deposited Pt on CeO2 by the atomic layer deposition technique not only can serve as the catalyst to generate oxygen vacancies under mild temperature reduction through the hydrogen spillover effect, but also can stabilize the generated oxygen vacancies. Meanwhile, the oxygen vacancies also provide anchoring sites for Pt forming strong metal-support interactions and thus preventing their agglomerations. Importantly, the Pt/CeO2- x reduced at 350 °C (Pt/CeO2- x -350R) exhibits excellent enzyme-mimicking catalytic activity for generation of reactive oxygen species (e.g., ·OH) as compared to other control samples, including CeO2 , Pt/CeO2 , and Pt/CeO2- x reduced at other temperatures, thus achieving excellent performance for tumor-specific catalytic therapy to efficiently eliminate cancer cells in vitro and ablate tumors in vivo. The excellent enzyme-mimicking catalytic activity of Pt/CeO2- x -350R originates from the good catalytic activities of oxygen vacancy-rich CeO2- x and Pt nanoclusters.

A Mild Hyperthermia Hollow Carbon Nanozyme as Pyroptosis Inducer for Boosted Antitumor Immunity

The immune checkpoint blockade (ICB) antibody immunotherapy has demonstrated clinical benefits for multiple cancers. However, the efficacy of immunotherapy in tumors is suppressed by deficient tumor immunogenicity and immunosuppressive tumor microenvironments. Pyroptosis, a form of programmed cell death, can release tumor antigens, activate effective tumor immunogenicity, and improve the efficiency of ICB, but efficient pyroptosis for tumor treatment is currently limited. Herein, we show a mild hyperthermia-enhanced pyroptosis-mediated immunotherapy based on hollow carbon nanozyme, which can specifically amplify oxidative stress-triggered pyroptosis and synchronously magnify pyroptosis-mediated anticancer responses in the tumor microenvironment. The hollow carbon sphere modified with iron and copper atoms (HCS-FeCu) with multiple enzyme-mimicking activities has been engineered to induce cell pyroptosis via the radical oxygen species (ROS)-Tom20-Bax-Caspase 3-gasdermin E (GSDME) signaling pathway under light activation. Both in vitro and in vivo antineoplastic results confirm the superiority of HCS-FeCu nanozyme-induced pyroptosis. Moreover, the mild photothermal-activated pyroptosis combining anti-PD-1 can enhance antitumor immunotherapy. Theoretical calculations further indicate that the mild photothermal stimulation generates high-energy electrons and enhances the interaction between the HCS-FeCu surface and adsorbed oxygen, facilitating molecular oxygen activation, which improves the ROS production efficiency. This work presents an approach that effectively transforms immunologically "cold" tumors into "hot" ones, with significant implications for clinical immunotherapy.

Deep Insight of Design, Mechanism, and Cancer Theranostic Strategy of Nanozymes

Since the discovery of enzyme-like activity of Fe3O4 nanoparticles in 2007, nanozymes are becoming the promising substitutes for natural enzymes due to their advantages of high catalytic activity, low cost, mild reaction conditions, good stability, and suitable for large-scale production. Recently, with the cross fusion of nanomedicine and nanocatalysis, nanozyme-based theranostic strategies attract great attention, since the enzymatic reactions can be triggered in the tumor microenvironment to achieve good curative effect with substrate specificity and low side effects. Thus, various nanozymes have been developed and used for tumor therapy. In this review, more than 270 research articles are discussed systematically to present progress in the past five years. First, the discovery and development of nanozymes are summarized. Second, classification and catalytic mechanism of nanozymes are discussed. Third, activity prediction and rational design of nanozymes are focused by highlighting the methods of density functional theory, machine learning, biomimetic and chemical design. Then, synergistic theranostic strategy of nanozymes are introduced. Finally, current challenges and future prospects of nanozymes used for tumor theranostic are outlined, including selectivity, biosafety, repeatability and stability, in-depth catalytic mechanism, predicting and evaluating activities.

Copper-Loaded Nanoheterojunction Enables Superb Orthotopic Osteosarcoma Therapy via Oxidative Stress and Cell Cuproptosis

Catalytic tumor therapy based on two-dimensional (2D) nanomaterials is a burgeoning and promising tumor therapeutic modality. However, the inefficient utilization and conversion of exogenous stimulation, single catalytic modality, and unsatisfactory therapeutic efficiency in the tumor microenvironment (TME) have seriously restricted their further application in tumor therapy. Herein, the heterogeneous carbon nitride-based nanoagent named T-HCN@CuMS was successfully developed, which dramatically improved the efficiency of the tumor therapeutic modality. Benefiting from the donor-acceptor (triazine-heptazine) structure within the heterogeneous carbon nitride nanosheets (HCN) and the construction of interplanar heterostructure with copper loaded metallic molybdenum bisulfide nanosheets (CuMS), T-HCN@CuMS presented a favorable photo-induced catalytic property to generate abundant reactive oxygen species (ROS) under near-infrared (NIR) light irradiation. Besides, the choice of CuMS simultaneously enabled this nanoagent to efficiently catalyze the Fenton-like reaction and trigger cell cuproptosis, a recently recognized regulated cell death mode characterized by imbalanced intracellular copper homeostasis and aggregation of lipoylated mitochondrial proteins. Moreover, upon surface modification with cRGDfk-PEG2k-DSPE, T-HCN@CuMS was prepared and endowed with improved dispersibility and αvβ3 integrins targeting ability. In general, through the rational design, T-HCN@CuMS was facilely prepared and had achieved satisfactory antitumor and antimetastasis outcomes both in vitro and in a high-metastatic orthotopic osteosarcoma model. This strategy could offer an idea to treat malignant diseases based on 2D nanomaterials.

Precise antibacterial therapeutics based on stimuli-responsive nanomaterials

Bacterial infection refers to the process in which bacteria invade, grow, reproduce, and interact with the body, ultimately causing a series of pathological changes. Nowadays, bacterial infection remains a significant public health issue, posing a huge threat to human health and a serious financial burden. In the post-antibiotic era, traditional antibiotics are prone to inducing bacterial resistance and difficulty in removing bacterial biofilm. In recent years, antibacterial therapy based on nanomaterials has developed rapidly. Compared with traditional antibiotics, nanomaterials effectively remove bacterial biofilms and rarely result in bacterial resistance. However, due to nanomaterials' strong permeability and effectiveness, they will easily cause cytotoxicity when they are not controlled. In addition, the antibacterial effect of non-responsive nanomaterials cannot be perfectly exerted since the drug release property or other antibacterial effects of these nano-materials are not be positively correlated with the intensity of bacterial infection. Stimuli-responsive antibacterial nanomaterials are a more advanced and intelligent class of nano drugs, which are controlled by exogenous stimuli and microenvironmental stimuli to change the dosage and intensity of treatment. The excellent spatiotemporal controllability enables stimuli-responsive nanomaterials to treat bacterial infections precisely. In this review, we first elaborate on the design principles of various stimuli-responsive antibacterial nanomaterials. Then, we analyze and summarizes the antibacterial properties, advantages and shortcomings of different applied anti-bacterial strategies based on stimuli-responsive nanomaterials. Finally, we propose the challenges of employing stimuli-responsive nanomaterials and corresponding potential solutions.

pH-Activated Scallop-Type Nanoenzymes for Oxidative Stress Amplification and Photothermal Enhancement of Antibacterial and Antibiofilm Effect

Ferric phosphate (FePOs) nanoenzymes can express peroxidase (POD) activity under the dual stimulation of an acidic environment and high H2O2 concentrations. In living organisms, this generates reactive oxygen species (ROS) in sites of lesion infection, and thus FePOs nanoenzymes can act as antimicrobial agents. Here, CeO2 and ZnO2 were immobilized in a scallop-type FePOs nanoenzyme material loaded with a photosensitizer, indocyanine green, to synthesize a multifunctional cascade nanoparticle system (FePOs-CeO2-ZnO2-ICG, FCZI NPs). H2O2 concentrations could be adjusted through the ZnO2 self-activation response to the slightly acidic environment in biofilms, further promoting the release of ROS from the POD-like reaction of FePOs, achieving amplification of oxidative stress, DNA and cell membrane damage, and exploiting the photodynamic/photothermal effects of indocyanine green to enhance the antibiofilm effects. CeO2 can remove redundant ROS by switching from Ce4+ to Ce3+ valence, enhancing its ability to fight chronic inflammation and oxidative stress and thus promoting the regeneration of tissues around infection. By maintaining the redox balance of normal cells, increasing ROS at the infection site, eliminating redundant ROS, and protecting normal tissues from damage, the synthesized system maximizes the elimination of biofilms and treatment at the infection site. Therefore, this work may pave the way for the application of biocompatible nanoenzymes.

A comprehensive exploration of the latest innovations for advancements in enhancing selectivity of nanozymes for theranostic nanoplatforms

Nanozymes have captured significant attention as a versatile and promising alternative to natural enzymes in catalytic applications, with wide-ranging implications for both diagnosis and therapy. However, the limited selectivity exhibited by many nanozymes presents challenges to their efficacy in diagnosis and raises concerns regarding their impact on the progression of disease treatments. In this article, we explore the latest innovations aimed at enhancing the selectivity of nanozymes, thereby expanding their applications in theranostic nanoplatforms. We place paramount importance on the critical development of highly selective nanozymes and present innovative strategies that have yielded remarkable outcomes in augmenting selectivities. The strategies encompass enhancements in analyte selectivity by incorporating recognition units, refining activity selectivity through the meticulous control of structural and elemental composition, integrating synergistic materials, fabricating selective nanomaterials, and comprehensively fine-tuning selectivity via approaches such as surface modification, cascade nanozyme systems, and manipulation of external stimuli. Additionally, we propose optimized approaches to propel the further advancement of these tailored nanozymes while considering the limitations associated with existing techniques. Our ultimate objective is to present a comprehensive solution that effectively addresses the limitations attributed to non-selective nanozymes, thus unlocking the full potential of these catalytic systems in the realm of theranostics.

A Dual Heat Shock Protein Down-Regulation Strategy Using PDA/Cu/ICG/R Controlled by NIR "Switch" Enhances Mild-Photothermal Therapy Effect

The purpose of this study is to down-regulate heat shock proteins and improve the mild photothermal therapy (mild-PTT) effect of polydopamine (PDA) by preparing the nanosystem of Cu2+ and indocyanine green (ICG)-loaded PDA nanospheres with surface modification of integrin-targeted cyclic peptide (cRGD) (PDA/Cu/ICG/R), which can limit ATP synthesis through the double mitochondrial destruction pathway. In vitro and in vivo experiments using PDA/Cu/ICG/R irradiated with an NIR laser demonstrate that when NIR is "OFF," Cu2+ can undergo Fenton-like reaction in tumor cells, producing a large amount of hydroxyl radicals (·OH), which leads to oxidative stress in cells. This oxidative stress can cause mitochondrial oxidative phosphorylation dysfunction, resulting in limited ATP synthesis. When NIR is "ON," mild-PTT can accelerate Cu2+ to produce ·OH. Simultaneously, NIR can activate ICG to produce reactive oxygen species (ROS) storm, amplify intracellular oxidative stress, and continuously damage mitochondria. The biodegradability of PDA greatly reduces the risk of toxicity caused by long-term retention of PDA/Cu/ICG/R in organisms. Finally, the improvement of the mild-PTT effect of PDA is successfully achieved through the double mitochondrial destruction pathway of Cu2+ and ICG controlled by NIR "switch."

A Series of Planar Phosphorescent Cyclometalated Platinum(II) Complexes as New Anticancer Theranostic Agents That Induce Oncosis

Herein, four planar cyclometalated platinum(II) complexes with a main ligand of enlarged aromatic rings have been assessed as effective anticancer theranostic agents for the first time. With an increased number of aromatic rings in the N∧N ligand, 1a-1d exhibit increased lipophilicity and cytotoxicity selectivity. The intensity of the Pt-Pt interaction of each complex can be indicated by an enhanced near-infrared (NIR) emission in phosphate-buffered saline (PBS), their binding activity with biomolecules of bovine serum albumin (BSA) is accompanied by a vivid turn-on green emission, and the intensity gradually decreased from 1a to 1d, which is consistent with the docking of two complexes with BSA. Both "turn-on" NIR and green emission of 1d can be mainly observed in nuclei of living cell within 24 h, while two phosphorescence traces of 1b were recorded in lysosomes by confocal imaging. Moreover, 1d shows the highest efficiency in inducing oncosis of Hela cells, and the relative process was investigated.

Gadolinium-Doped Carbon Nanodots as Potential Anticancer Tools for Multimodal Image-Guided Photothermal Therapy and Tumor Monitoring

This study focuses on the synthesis and characterization of gadolinium-doped carbon nanodots (CDs-Gd) and their potential applications in multimodal imaging and precision cancer therapy. CDs-Gd were synthesized through a solvothermal decomposition method combining citric acid, GdCl3, and urea. The incorporation of Gd3+ ions within the carbonaceous structure resulted in stable CDs-Gd with a peculiar architecture that retained optical and paramagnetic properties. Combined characterization techniques confirmed the presence of pH-sensitive COOH functions on the CDs-Gd surface along with the unique lattice structure induced by Gd3+ doping. The optical properties of CDs-Gd exhibited a tunable emission spectrum displaying blue-green emission with pH-dependent behavior. Additionally, CDs-Gd exhibited contrast-enhancing properties in T1-weighted magnetic resonance imaging (MRI) experiments. MRI acquisitions at different Gd3+ concentrations and pH values demonstrated the potential of CDs-Gd as contrast agents for monitoring pH changes in an aqueous environment. We found that the relaxivity of CDs-Gd at pH 5.5 (tumor, 11.3 mM-1 s-1) is roughly 3-fold higher than that observed at pH 7.4 (physiological, 5.0 mM-1 s-1) and outperformed clinical standards such as γ-butyrol (3.3 mM-1 s-1). Monitoring pH changes in tumor microenvironment (TME) is crucial for evaluating the effectiveness of anticancer treatments and understanding tumor progression. Furthermore, CDs-Gd demonstrated concentration-dependent photothermal conversion ability in the near-infrared (NIR) region, allowing for efficient heat generation under laser irradiation. This indicates the potential application of CDs-Gd in image-guided photothermal therapy (IG-PTT) for cancer treatment. The in vitro studies on MCF-7 (breast cancer) and 16-HBE (healthy bronchial epithelium) cell lines demonstrated that CDs-Gd exhibited high biocompatibility (cell viability >80%). However, upon NIR activation, they showed potent anticancer effects by inhibiting tumor cell proliferation and inducing apoptosis selectively in cancer cells. In conclusion, the synthesized CDs-Gd nanoparticles possess unique optical, photothermal, and MRI contrast properties, making them promising candidates for multimodal imaging-guided precision cancer therapy applications.

AuPt-Loaded Cu-Doped Polydopamine Nanocomposites with Multienzyme-Mimic Activities for Dual-Modal Imaging-Guided and Cuproptosis-Enhanced Photothermal/Nanocatalytic Therapy

Nanocatalytic therapy (NCT) has made great achievements in tumor treatments due to its remarkable enzyme-like activities and high specificity. Nevertheless, the limited types of nanozymes and undesirable tumor microenvironments (TME) greatly weaken the therapeutic efficiency. Developing a combination therapy integrating NCT and other strategies is of great significance for optimal treatment outcomes. Herein, a AuPt-loaded Cu-doped polydopamine nanocomposite (AuPt@Cu-PDA) with multiple enzyme-like activities was rationally designed, which integrated photothermal therapy (PTT) and NCT. The peroxidase (POD)-like activity of AuPt@Cu-PDA can catalyze hydrogen peroxide (H2O2) into ·OH, and the catalase (CAT)-mimic activity can decompose H2O2 into O2 to alleviate hypoxia of TME, and O2 can be further converted into toxic ·O2- by its oxidase (OXD)-mimic activity. In addition, Cu2+ in AuPt@Cu-PDA can effectively consume GSH overexpressed in tumor cells. The boosting of reactive oxygen species (ROS) and glutathione (GSH) depletion can lead to severe oxidative stress, which can be enhanced by its excellent photothermal performance. Most importantly, the accumulation of Cu2+ can disrupt copper homeostasis, promote the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT), disrupt the mitochondrial tricarboxylic acid (TCA) cycle, and finally result in cuproptosis. Collectively, photothermal and photoacoustic imaging (PTI/PAI)-guided cuproptosis-enhanced NCT/PTT can be achieved. This work may expand the application of nanozymes in synergistic therapy and provide new insights into cuproptosis-related therapeutic strategies.