Near-Infrared-II Plasmonic Trienzyme-Integrated Metal-Organic Frameworks with High-Efficiency Enzyme Cascades for Synergistic Trimodal Oncotherapy

Emerging glucose oxidase-delivering nanomedicines for enhanced tumor therapy

Abnormalities in glucose metabolism have been shown to characterize malignant tumors. Glucose depletion by glucose oxidase (GOD) has shown great potential in tumor therapy by causing tumor starvation. Since 2017, nanomedicines have been designed and utilized to deliver GOD for more precise and effective glucose modulation, which can overcome intrinsic limitations of different cancer therapeutic modalities by remodeling the tumor microenvironment to enhance antitumor therapy. To date, the topic of GOD-delivering nanomedicines for enhancing tumor therapy has not been comprehensively summarized. Herein, this review aims to provide an overview and discuss in detail recent advances in GOD delivery and directly involved starvation therapy strategies, GOD-sensitized various tumor therapy strategies, and GOD-mediated multimodal antitumor strategies. Finally, the challenges and outlooks for the future progress of the emerging tumor therapeutic nanomedicines are discussed. This review provides intuitive and specific insights to a broad audience in the fields of nanomedicines, biomaterials, and cancer therapy.

Semiconducting Open-Shell Radicals for Precise Tumor Activatable Phototheranostics

Semiconducting open-shell radicals (SORs) have promising potential for the development of phototheranostic agents, enabling tumor bioimaging and boosting tumorous reactive oxygen species (ROS). Herein, a new class of semiconducting perylene diimide (PDI), designated as PDI(Br)n with various numbers of bromine (Br) atoms modified on PDI's bay/ortho positions is reported. PDI(Br)n is demonstrated to transform into a radical anion, [PDI(Br)n]•-, in a reducing solution, with a typical g-value of 2.0022. Specifically, [PDI(Br)4/6]•- is generated in the weakly reductive tumor-mimicking solution and exhibits high stability in air. Quantum chemical kinetic simulation and ultrafast femtosecond transient absorption spectroscopy indicate that [PDI(Br)6]•- has a low π-π stacking energy (0.35 eV), a fast electron transfer rate (192.4 ps) and energy gap of PDI(Br)6 (ΔES1, T1 = 1.307 eV, ΔES1, T2 = 0.324 eV) respectively, which together result in excited-state charge transfer characters. The PDI(Br)6 nanoparticle radicals, [PDI(Br)6] NPs•-, specifically enable chemodynamic and type-I photodynamic ROS generation in tumors, including superoxide and hydroxyl radicals, which elicit immunogenic cell death effect. Also, [PDI(Br)6] NPs•- facilitate activatable bioimaging-guided therapy due to their photoacoustic signal at 808 nm and NIR-II emission at 1115 nm. The work paves the way for the design of SORs for precise cancer theranostics.

Synchronously Evoking Disulfidptosis and Ferroptosis via Systematical Glucose Deprivation Targeting SLC7A11/GSH/GPX4 Antioxidant Axis

Disulfidptosis and ferroptosis are recently identified programmed cell deaths for tumor therapy, both of which highly depend on the intracellular cystine/cysteine transformation on the cystine transporter solute carrier family 7 member 11/glutathione/glutathione peroxidase 4 (SLC7A11/GSH/GPX4) antioxidant axis. However, disulfidptosis and ferroptosis are usually asynchronous due to the opposite effect of cystine transport on them. Herein, systematic glucose deprivation, by both inhibiting upstream glucose uptake and promoting downstream glucose consumption, is proposed to synchronously evoke disulfidptosis and ferroptosis. As an example, Au nanodots and Fe-apigenin (Ap) complexes coloaded FeOOH nanoshuttles (FeOOH@Fe-Ap@Au NSs) are employed to regulate the SLC7A11/GSH/GPX4 axis for performing disulfidptosis- and ferroptosis-mediated tumor therapy synchronously. In this scenario, Au nanodots exhibit glucose oxidase-like activity when consuming massive glucose. Meanwhile, Ap can inhibit glucose uptake by downregulating glucose transporter 1, depriving glucose fundamentally. The systematical glucose deprivation limits the supplement of NADPH and suppresses cystine/cysteine transformation on the SLC7A11/GSH/GPX4 axis, thus solving the contradiction of cystine transport on disulfidptosis and ferroptosis. In addition, the efficient delivery of exogenous iron ions by FeOOH@Fe-Ap@Au NSs and self-supplied H2O2 through Au nanodots-catalytic glucose oxidation facilitate intracellular Fenton reaction and therewith help to amplify ferroptosis. As a result of synchronous occurrence of disulfidptosis and ferroptosis, FeOOH@Fe-Ap@Au NSs exhibit good efficacy in an ovarian cancer therapeutic model.

Temperature-Sensitive Nano-GOx Combined with Downregulation of Tumor Stemness to Initiate Robust Antitumor Efficacy

GOx-mediated glucose depletion offers an alternative noninvasive strategy for tumor therapy, but its lower catalytic activity in vivo limits its clinical application. Herein, we designed a temperature-sensitive nano-GOx (NG) that was constructed by gold nanorods chemically modified with GOx (AuNRs-GOx) and coated with temperature-sensitive lipids. The chemical linkage could maintain the natural conformation of GOx, ensuring that NG exerted powerful catalytic activity within the tumor and initiated antitumor immune response through moderate starvation and mild photothermal therapy (mPTT) to coregulating dendritic cells (DCs) and tumor-associated macrophages (TAMs). Ulteriorly, VTNG was obtained by NG coloading with verteporfin (VP) and evofosfamide (TH-302). VTNG demonstrated temperature-sensitive triggered drug release when exposed to near-infrared laser irradiation. NG exacerbated the degree of TME hypoxia and facilitated the activation of TH-302. Meanwhile, VP enhanced tumor cell sensitivity by decreasing the stemness of the tumor cells, thus realizing the effective killing of tumor cells and further enhancing the therapeutic effect of NG. Notably, VTNG had a significant antitumor effect in melanoma models compared with first-line melanoma therapy and formed an immune memory effect. In conclusion, VTNG provided an effective approach to enhance the therapeutic effect of GOx for tumor treatment.

Mitoxantrone-Encapsulated ZIF-8 Enhances Chemo-Immunotherapy via Amplified Immunogenic Cell Death

Chemo-immunotherapy, combining systemic chemotherapeutic drugs and immune checkpoint blockers, is a promising paradigm in cancer treatment. However, challenges such as limited induction of immune responses and systemic immune toxicity have hindered its clinical applications. Here, a zeolite imidazolate framework-8 (ZIF-8) that encapsulates mitoxantrone (MIT), an immune cell death (ICD)-inducing chemotherapeutic agent (MIT@ZIF-8), is synthesized using a one-pot aqueous-phase process. ZIF-8 serves as a dual-functional nanomaterial for chemo-immunotherapy: a carrier to enhance tumor uptake of MIT for improved chemotherapy efficacy, and a pyroptosis inducer to amplify MIT-induced ICD for augmented anti-tumor immune responses. As a result, in vivo administration of MIT@ZIF-8 markedly inhibits tumor growth in both immunologically "hot" colon cancer and immunologically "cold" prostate cancer. Moreover, MIT@ZIF-8 treatment increases the abundance of cytotoxic CD8+ T cells and reduces the amount of immunosuppressive regulatory T cells in tumors, thereby enhancing anti-tumor immunity and sensitizing prostate cancer to anti-CTLA-4 immunotherapy. In summary, MIT@ZIF-8 offers a highly translational approach for chemo-immunotherapy.

Biocatalytic cascade reactions for management of diseases

Biocatalytic cascade reactions, which evolve from the confinement of multiple enzymes within living cells, represent a promising strategy for disease management. Using tailor-made nanoplatforms, reactions induced by multiple enzymes and/or nanozymes can be precisely triggered at pathogenic sites. These promote further cascade reactions that generate therapeutic species prompting effective therapeutic outcomes with minimal side effects. Over the past few years, this approach has seen widespread applications in disease management. This review attempts to critically assess and summarize the recent advances in the use of biocatalytic cascade reactions for the management of diseases. Emphasis is placed on the design of cascade catalytic systems of high efficiency and selectivity and the implementation of specific cascade processes that respond to the endogenous substances produced in the pathological processes. The various types of biocatalytic cascade reactions are outlined according to the timeline of the catalytic steps through a series of reported examples. The challenges and outlook in the field are also discussed to encourage the further development of personalized treatments based on biocatalytic cascade reactions.

Ligand engineering boosts catalase-like activity of gold nanoclusters for cascade reactions combined with glucose oxidase in ZIF-8 matrix

BACKGROUND

Integrating natural enzymes and nanomaterials exhibiting tailored enzyme-like activities is an effective strategy for the application of cascade reactions. It is essential to develop a highly efficient and robust glucose oxidase-catalase (GOx-CAT) cascade system featuring controllable enzyme activity, a reliable supply of oxygen, and improved stability for glucose depletion in cancer starvation therapy. However, the ambiguous relationship between structure and performance, and the difficulty in controlling enzyme-mimic activity, significantly hinder their broader application. Herein, the CAT-like activity of atomically precise Au25(MPA)18 (MPA = 3-mercaptopropionic acid) nanoclusters (AuNCs) was modulated by incorporating N-acetyl-l-cysteine (NAC) in a series of ratio.

RESULTS

It is found that Au25(NAC)14-17(MPA)4-1 exhibited superior CAT-like activity and structural stability than Au25(MPA)18 owing to the intramolecular hydrogen bond in NAC. Moreover, the synergetic effects of glucose-depletion catalyzed by GOx, oxygen generation from the intermediate hydrogen peroxide (H2O2) facilitated by Au25(NAC)14-17(MPA)4-1, and protective function and nanoconfinement effect of zeolitic imidazolate framework-8 (ZIF-8) enabled the GOx-Au25(NAC)14-17(MPA)4-1@ZIF-8 composite to degrade more glucose. Compared to that treated with a single enzyme or free enzymes, the residual intermediate H2O2 level after treatment with GOx-Au25(NAC)14-17(MPA)4-1@ZIF-8 was about 93 % lower than that after treatment with GOx alone. This composite showed higher catalytic activity, stability, and tolerance when applied to GOx-mediated glucose depletion.

SIGNIFICANCE

In brief, the study provides a feasible strategy for realizing robust and efficient cascade reaction by integrating the merits of natural enzymes and atomically precise metal NCs with adjustable enzyme-like activity. This research offers essential guidance for developing a biocompatible and tailored cascade system.

A Near-Infrared II Photo-Triggered Multifunctional Plasmonic Hyperthermia Immunomodulator for SERS-Guided Combination Cancer Immunotherapy

Immunotherapy represents a promising therapeutic strategy for cancer treatment, but its clinical applications are currently hindered by insufficient therapeutic potency, nonspecific delivery, and adverse side effects. Herein, a novel near-infrared II (NIR-II) photo-triggered plasmonic hyperthermia immunomodulator (RP@IR-pcNS@HA nanoparticles (NPs)) for anticancer treatment of both primary and distant cancers is reported. This immunomodulator comprises an IR-1061 dye-encoded NIR-II porous cubic AuAg nanoshell (pcNS) loaded with a Toll-like receptor 7 agonist - R837 in phase change materials (PCMs), further modified with hyaluronic acid (HA). In response to NIR-II photoirradiation, the RP@IR-pcNS@HA NPs controllably deliver and release R837 to tumor sites, subsequently perform plasmonic hyperthermia therapy for direct ablation of primary tumors, and elicit robust anticancer immune responses. It is demonstrated that upon NIR-II irradiation, such a plasmonic hyperthermia immunomodulator combined with anti-programmed death 1 antibody (αPD-1) completely eradicates both primary and distant cancers. In addition, this combination treatment successfully elicits robust immune memory responses for effective suppression of recurrence and distant metastasis of cancer. With the excellent NIR-II surface-enhanced Raman scattering (SERS) detection ability, the RP@IR-pcNS@HA NPs combined with αPD-1 represent an efficient way to develop high-performance theranostic agents for SERS-guided combination cancer photoimmunotherapy.

Efficient bionic nanozyme based on AuPt NPs@ZIF-90 used for cyclic catalysis multimodal tumor therapy

Multimodal therapy based on nanozyme is expected to become a novel option for tumor treatment. However, the catalytic efficiency of nanozymes and the hypoxia microenvironment of tumors limit the therapeutic effect of nanozymes. Herein, we screened a small molecule of midazole-2-carboxaldehyde (ICA) to prepare ZIF-90 and embedded gold and platinum nanoparticles to obtain ZAAP. ZAAP possessed a multi-enzymatic cascade of catalytic processes including greatly enhanced peroxidase activity via a "bionic" catalytic microenvironment (enhanced 23-fold), catalase and glucose oxidase activities, resulting in glucose decomposition to continuously supply H2O2, peroxidases for the catabolism of H2O2 to generate ROS and peroxidase-induced oxygen generation for continuous oxidation of glucose. All the above processes built a catalysis cycle that greatly promotes the generation of ROS and oxygen as well as the consumption of glucose, leading to the chemical dynamic therapy function and alleviating tumor hypoxia. In addition to the photothermal effect of ZAAP, a synergistic treatment of chemical dynamic/photothermal/starvation therapy was achieved, and the tumor inhibition rate reached 96.4% within 2 weeks, indicating that ZAAP shows great potential in nanozyme-based synergistic multimodal tumor treatment.

Applications of nanotheranostics in the second near-infrared window in bioimaging and cancer treatment

Achieving accurate and efficient tumor imaging is crucial in the field of tumor treatment, as it facilitates early detection and precise localization of tumor tissues, thereby informing therapeutic strategies and surgical interventions. The optical imaging technology within the second near-infrared (NIR-II) window has garnered significant interest for its remarkable benefits, such as enhanced tissue penetration depth, superior signal-to-background ratio (SBR), minimal tissue autofluorescence, reduced photon attenuation, and lower tissue scattering. This review explained the design and optimization strategies of nano-agents responsive to the NIR-II window, such as single-walled carbon nanotubes, quantum dots, lanthanum-based nanomaterials, and noble metal nanomaterials. These nano-agents enable non-invasive, deep-tissue imaging with high spatial resolution in the NIR-II window, and their superior optical properties significantly improve the accuracy, efficiency, and versatility of imaging-guided tumor treatments. And we discussed the characteristics and advantages of fluorescence imaging (FL)/photoacoustic imaging (PA) in NIR-II window, providing a comprehensive overview of the latest research progress of different nano-agents in FL/PA imaging-guided tumor therapy. Furthermore, we exhaustively reviewed the latest applications of multifunctional nano-phototherapy technologies carried out by NIR-II light including photothermal therapy (PTT), photodynamic therapy (PDT), and combined modalities like photothermal-chemodynamic therapy (PTT-CDT), photothermal-chemotherapy (PTT-CT), and photothermal- immunotherapy (PTT-IO). These imaging-guided integrated tumor therapy approaches within the NIR-II window have gradually matured over the past decade and are expected to become a safe and effective non-invasive tumor treatment. Finally, we outlined the prospects and challenges of development and innovation of the NIR-II integrated diagnosis and therapy nanoplatform. This review aims to provide insightful perspectives for future advancements in NIR-II optical tumor diagnosis and integrated treatment platforms.

Biomineralized ZIF-8 Encapsulating SOD from Hydrogenobacter Thermophilus: Maintaining Activity in the Intestine and Alleviating Intestinal Oxidative Stress

Oxidative stress is a major factor leading to inflammation and disease occurrence, and superoxide dismutase (SOD) is a crucial antioxidative metalloenzyme capable of alleviating oxidative stress. In this study, a novel thermostable SOD gene is obtained from the Hydrogenobacter thermophilus strain (HtSOD), transformed and efficiently expressed in Escherichia coli with an activity of 3438 U mg-1, exhibiting excellent thermal stability suitable for scalable production. However, the activity of HtSOD is reduced to less than 10% under the acidic environment. To address the acid resistance and gastrointestinal stability issues, a biomimetic mineralization approach is employed to encapsulate HtSOD within the ZIF-8 (HtSOD@ZIF-8). Gastrointestinal simulation results show that HtSOD@ZIF-8 maintained 70% activity in simulated gastric fluid for 2 h, subsequently recovering to 97% activity in simulated intestinal fluid. Cell and in vivo experiments indicated that HtSOD@ZIF-8 exhibited no cytotoxicity and do not impair growth performance. Furthermore, HtSOD@ZIF-8 increased the relative abundance of beneficial microbiota such as Dubosiella and Alistipes, mitigated oxonic stress and intestinal injury by reducing mitochondrial and total reactive oxygen species (ROS) levels in diquat-induced. Together, HtSOD@ZIF-8 maintains and elucidates activity in the intestine and biocompatibility, providing insights into alleviating oxidative stress in hosts and paving the way for scalable production.

Traditional Chinese medicine-based drug delivery systems for anti-tumor therapies

The treatment of tumors continues to be significantly challenging. The presence of multiple modalities, including surgery, radiation, chemotherapy and immunotherapy, the therapeutic outcomes remain limited and are often associated with adverse effects and inconsistent efficacy across cancer types. Recent studies have highlighted the potential of active components from traditional Chinese medicine (TCM) for their anti-cancer properties, which are attributable to multi-targeted mechanisms and broad pharmacological actions. Despite this potential, TCM-derived compounds are commonly limited by poor water solubility, low bioavailability, and suboptimal targeting. Currently, it is believed that advances in nanotechnology could address these limitations. Nanoparticles (NPs), which possess properties such as enhanced bioavailability, controlled release and precise targeting, have been used to improve the therapeutic efficacy of TCM components in cancer therapy. This review discusses the use of NPs for the delivery of active TCM compounds via organic-inorganic nanocarriers, highlighting innovative strategies that enhance the effectiveness of TCM-based anti-tumor components to provide insights into improving clinical outcomes while advancing the modernization and global application of TCM in oncology.

Coacervation-Driven Semipermeable Nanoreactors for Enzymatic Cascade-Mediated Cancer Combination Therapy with Enhanced Efficacy

Utilizing enzyme cascades as a promising approach for targeted cancer therapies holds significant potential, yet its clinical effectiveness is substantially hindered by functional losses during delivery. Complex coacervation emerges as an intriguing strategy for designing functional nanoreactors. In this study, a noteworthy achievement is presented in the development of lactobionic acid-modified tumor microenvironment (TME)-responsive polyelectrolyte complex vesicles (HGS-PCVs) based on bioinspired homopolypeptoids, which serve as a facile, intelligent, and highly efficient nanoreactor tunable for glucose oxidase, hemoglobin, and sorafenib (SRF) to hepatic cancer cells. The TME-responsive permeability of HGS-PCVs enables the selective entry of glucose into their interior, triggering an enzymatic cascade reaction within the tumor. This intricate process generates toxic hydroxyl radicals while concurrently lowering the pH. Consequently, this pH shift enhances the SRF release, effectively promoting ferroptosis and apoptosis in the target cancer cells. Further, the administration of the HGS-PCVs not only initiates immunogenic cell death but also plays a crucial role in inducing the maturation of dendritic cells within lymph nodes. It stimulates an adaptive T-cell response, a crucial mechanism that contributes to impeding the growth of distant tumors in vivo, demonstrating the promising potential of PCVs for cancer immunotherapy.

Exploring enzyme-immobilized MOFs and their application potential: biosensing, biocatalysis, targeted drug delivery and cancer therapy

Enzymes are indispensable in several applications including biosensing and degradation of pollutants and in the drug industry. However, adverse conditions restrict enzymes' utility in biocatalysis due to their inherent limitations. Metal-organic frameworks (MOFs), with their robust structure, offer an innovative avenue for enzyme immobilization, enhancing their resilience against harsh solvents and temperatures. This advancement is pivotal for application in bio-sensing, bio-catalysis, and specifically, targeted drug delivery in cancer therapy, where enzyme-MOF composites enable precise therapeutic localization, minimizing the side effects of traditional treatment. The adaptable nature of MOFs enhances drug biocompatibility and availability, significantly improving therapeutic outcomes. Moreover, the integration of enzyme-immobilized MOFs into bio-sensing represents a leap forward in the rapid and accurate identification of biomarkers, facilitating early diagnosis and disease monitoring. In bio-catalysis, this synergy promotes efficient and environmentally safe chemical synthesis, enhancing reaction rates and yields and broadening the scope of enzyme application in pharmaceutical and bio-fuel production. This review article explores the immobilization techniques and their biomedical applications, specifically focusing on drug delivery in cancer therapy and bio-sensing. Additionally, it addresses the challenges faced in this expanding field.

Zinc-Based ROS Amplifiers Trigger Cancer Chemodynamic/Ion Interference Therapy Through Self-Cascade Catalysis

Nanozyme-mediated chemodynamic therapy has emerged as a promising strategy due to its tumor specificity and controlled catalytic activity. However, the poor efficacy caused by low hydrogen peroxide (H2O2) levels in the tumor microenvironment (TME) poses challenges. Herein, an H2O2 self-supplying nanozyme is constructed through loading peroxide-like active platinum nanoparticles (Pt NPs) on zinc peroxide (ZnO2) (denoted as ZnO2@Pt). ZnO2 releases H2O2 in response to the acidic TME. Pt NPs catalyze the hydroxyl radical generation from H2O2 while reducing the mitigation of oxidative stress by glutathione, serving as a reactive oxygen (ROS) amplifier through self-cascade catalysis. In addition, Zn2+ released from ZnO2 interferes with tumor cell energy supply and metabolism, enabling ion interference therapy to synergize with chemodynamic therapy. In vitro studies demonstrate that ZnO2@Pt induces cellular oxidative stress injury through enhanced ROS generation and Zn2+ release, downregulating ATP and NAD+ levels. In vivo assessment of anticancer effects showed that ZnO2@Pt could generate ROS at tumor sites to induce apoptosis and downregulate energy supply pathways associated with glycolysis, resulting in an 89.7% reduction in tumor cell growth. This study presents a TME-responsive nanozyme capable of H2O2 self-supply and ion interference therapy, providing a paradigm for tumor-specific nanozyme design.

Nanozymes-Mediated Cascade Reaction System for Tumor-Specific Diagnosis and Targeted Therapy

Cascade reactions are described as efficient and versatile tools, and organized catalytic cascades can significantly improve the efficiency of chemical interworking between nanozymes. They have attracted great interest in many fields such as chromogenic detection, biosensing, tumor diagnosis, and therapy. However, how to selectively kill tumor cells by enzymatic reactions without harming normal cells, as well as exploring two or more enzyme-engineered nanoreactors for cascading catalytic reactions, remain great challenges in the field of targeted and specific cancer diagnostics and therapy. The latest research advances in nanozyme-catalyzed cascade processes for cancer diagnosis and therapy are described in this article. Here, various sensing strategies are summarized, for tumor-specific diagnostics. Targeting mechanisms for tumor treatment using cascade nanozymes are classified and analyzed, "elements" and "dimensions" of cascade nanozymes, types, designs of structure, and assembly modes of highly active and specific cascade nanozymes, as well as a variety of new strategies of tumor targeting based on the cascade reaction of nanozymes. Finally, the integrated application of the cascade nanozymes systems in tumor-targeted and specific diagnostic therapy is summarized, which will lay the foundation for the design of more rational, efficient, and specific tumor diagnostic and therapeutic modalities in the future.

Cascade Enzymes Confined in DNA Nanoanchors for Antitumor Therapy

Cascade-enzyme reaction systems have emerged as promising tools for treating malignant tumors by efficiently converting nutrients into toxic substances. However, the challenges of poor localized retention capacity and utilization of highly active enzymes often result in extratumoral toxicity and reduced therapeutic efficacy. In this study, we introduced a cell membrane-DNA nanoanchor (DNANA) with a spatially confined cascade enzyme for in vivo tumor therapy. The DNANAs are constructed using a polyvalent cholesterol-labeled DNA triangular prism, ensuring high stability in cell membrane attachment. Glucose oxidase (GOx) and horseradish peroxidase (HRP), both modified with streptavidin, are precisely confined to biotin-labeled DNANAs. Upon intratumoral injection, DNANA enzymes efficiently colonize the tumor site through cellular membrane engineering strategies, significantly reducing off-target enzyme leakage and the associated risks of extratumoral toxicity. Furthermore, DNANA enzymes demonstrated effective cancer therapy in vitro and in vivo by depleting glucose and producing highly cytotoxic hydroxyl radicals in the vicinity of tumor cells. This membrane-engineered cascade-enzyme reaction system presents a conceptual approach to tumor treatment.

Molecular-Sieving Label-Free Surface-Enhanced Raman Spectroscopy for Sensitive Detection of Trace Small-Molecule Biomarkers in Clinical Samples

Small-molecule biomarkers are ubiquitous in biological fluids with pathological implications, but major challenges persist in their quantitative analysis directly in complex clinical samples. Herein, a molecular-sieving label-free surface-enhanced Raman spectroscopy (SERS) biosensor is reported for selective quantitative analysis of trace small-molecule trimetazidine (TMZ) in clinical samples. Our biosensor is fabricated by decorating a superhydrophobic monolayer of microporous metal-organic frameworks (MOF) shell-coated Au nanostar nanoparticles on a silicon substrate. The design strategy principally combines the hydrophobic surface-enabled physical confinement and preconcentration, MOF-assisted molecular enrichment and sieving of small molecules, and sensitive SERS detection. Our biosensor utilizes such a "molecular confinement-and-sieving" strategy to achieve a five orders-of-magnitude dynamic detection range and a limit of detection of ≈0.5 nM for TMZ detection in either urine or whole blood. We further demonstrate the applicability of our biosensing platform for longitudinal label-free SERS detection of the TMZ level directly in clinical samples in a mouse model.

Zwitterionic Polyelectrolyte Complex Vesicles Assembled from Homopoly(2-Oxazoline)s as Enzyme Catalytic Nanoreactors for Potent Anti-Tumor Efficiency

Enzymes are known for their remarkable catalytic efficiency across a wide range of applications. Here, we present a novel and convenient nanoreactor platform based on zwitterionic polyelectrolyte complex vesicles (PCVs), assembled from oppositely charged homopoly(2-oxazoline)s, facilitating enzyme immobilization. We show remarkable enhancements in catalytic activity and stability by encapsulation of lipase as a model enzyme. Even as the temperature rises, the performance of the lipase remains robust. Further, the structural characteristics of PCVs, including hollow architecture and semipermeable membranes, endow them with unique advantages for enzyme cascade reactions involving glucose oxidase (GOx) and horseradish peroxidase (HRP). A decline in catalytic efficiency is shown when the enzymes are individually loaded and subsequently mixed, in contrast to the coloaded GOx-HRP-PCV group. We demonstrate that the vesicle structures establish confined environments where precise enzyme-substrate interactions facilitate enhanced catalytic efficiency. In addition, the nanoreactors exhibit excellent biocompatibility and efficient anti-tumor activity, which hold significant promise for biomedical applications within enzyme-based technologies.

Microfluidic-Enabled Assembly of Multicomponent Artificial Organelle for Synergistic Tumor Starvation Therapy

Artificial organelles (AOs) encapsulating enzymes are engineered to facilitate biocatalytic reactions for exerting therapeutic effects in various diseases. Exploiting the confinement effect, these catalytic properties exhibit significant enhancements without being influenced by the surrounding medium, enabling more efficient cascade reactions. In this study, we present a novel approach for synergistic tumor starvation therapy by developing multicomponent artificial organelles that combine enzymatic oncotherapy with chemotherapy. The construction process involves a microfluidic-based approach that enables the encapsulation of cationic cores containing doxorubicin (DOX), electrostatic adsorption of cascade enzymes, and surface assembly of the protective lipid membrane. Additionally, these multicomponent AOs possess multicompartment structures that enable the separation and sequential release of each component. By coencapsulating enzymes and chemotherapeutic agent DOX within AOs, we achieve enhanced enzymatic cascade reactions (ECR) and improved intrinsic permeability of DOX due to spatial confinement. Furthermore, exceptional therapeutic effects on 4T1 xenograft tumors are observed, demonstrating the feasibility of utilizing AOs as biomimetic implants in living organisms. This innovative approach that combines starvation therapy with chemotherapy using multicompartment AOs represents a promising paradigm in the field of precise cancer therapy.

A simple and reliable interenzyme distance regulation strategy based on a DNA quadrangular prism scaffold for ultrasensitive ochratoxin A detection

Developing sensitive and accurate Ochratoxin A (OTA) detection methods is essential for food safety. Herein, a simple and reliable strategy for regulating interenzyme distance based on a rigid DNA quadrangular prism as a scaffold was proposed to establish a new electrochemical biosensor for ultrasensitive detection of OTA. The interenzyme distances were precisely adjusted by changing the sequences of the hybridized portions of hairpins SH1 and SH2 to the DNA quadrangular prism, avoiding the complexity and instability of the previous DNA scaffold-based enzyme spacing adjustment strategies. The electrochemical biosensor constructed at the optimal interenzyme distance (10.4 nm) achieved sensitive detection of OTA in a dynamic concentration range from 10 fg/mL to 250 ng/mL with a detection limit of 3.1 fg/mL. In addition, the biosensor was applied to quantify OTA in real samples, exhibiting great application potential in food safety.

Radiotherapy-sensitized cancer immunotherapy via cGAS-STING immune pathway by activatable nanocascade reaction

Radiotherapy-induced immune activation holds great promise for optimizing cancer treatment efficacy. Here, we describe a clinically used radiosensitizer hafnium oxide (HfO2) that was core coated with a MnO2 shell followed by a glucose oxidase (GOx) doping nanoplatform (HfO2@MnO2@GOx, HMG) to trigger ferroptosis adjuvant effects by glutathione depletion and reactive oxygen species production. This ferroptosis cascade potentiation further sensitized radiotherapy by enhancing DNA damage in 4T1 breast cancer tumor cells. The combination of HMG nanoparticles and radiotherapy effectively activated the damaged DNA and Mn2+-mediated cGAS-STING immune pathway in vitro and in vivo. This process had significant inhibitory effects on cancer progression and initiating an anticancer systemic immune response to prevent distant tumor recurrence and achieve long-lasting tumor suppression of both primary and distant tumors. Furthermore, the as-prepared HMG nanoparticles "turned on" spectral computed tomography (CT)/magnetic resonance dual-modality imaging signals, and demonstrated favorable contrast enhancement capabilities activated by under the GSH tumor microenvironment. This result highlighted the potential of nanoparticles as a theranostic nanoplatform for achieving molecular imaging guided tumor radiotherapy sensitization induced by synergistic immunotherapy.

Metal-Organic Framework Nanomaterials as a Medicine for Catalytic Tumor Therapy: Recent Advances

Nanomaterials, with unique physical, chemical, and biocompatible properties, have attracted significant attention as an emerging active platform in cancer diagnosis and treatment. Amongst them, metal-organic framework (MOF) nanostructures are particularly promising as a nanomedicine due to their exceptional surface functionalities, adsorption properties, and organo-inorganic hybrid characteristics. Furthermore, when bioactive substances are integrated into the structure of MOFs, these materials can be used as anti-tumor agents with superior performance compared to traditional nanomaterials. In this review, we highlight the most recent advances in MOFs-based materials for tumor therapy, including their application in cancer treatment and the underlying mechanisms.

Acid‐Unlocked Switch Controlled the Enzyme and CO In Situ Release to Induce Mitochondrial Damage via Synergy

CO gas therapy has attracted enormous attention in tumor therapy due to the abilities of mitochondrial damage and inhibition of cellular respiration. However, the inefficient and random release of CO greatly limit its application. Taking this into account, the study constructs an acid‐unlocked nanostructure based on MPDA‐MnCO‐GOx@DSNPs, designated as MMGD. The nanostructure enables tumor microenvironment (TME) specific enzyme and CO prodrug (manganese carbonyl, MnCO) cascade reaction, thus facilitating CO release in situ. Mesoporous polydopamine (MPDA) can provide the space for MnCO and glucose oxidase (GOx) loading. Especially, lanthanide (Ln3+)‐doped down‐shifting luminescent nanoparticles (DSNPs) can not only serve as the near‐infrared II (NIR‐II) fluorescence imaging probe, but also act as the acid‐unlocked gating switch. The slightly acidic TME can render the dissociation of DSNPs, thus exposing GOx and releasing MnCO. The catalytic reaction of GOx can produce H2O2 and create a more acidic environment, which facilitates the CO generation in situ, leading to mitochondrial damage by reducing cytochrome c oxidase activity and adenosine triphosphate (ATP) levels. Meanwhile, MPDA has the NIR light absorption capability for photothermal therapy (PTT). This study provides an ingenious strategy for efficient and controllable CO gas, starvation, and PTT of tumor guided by NIR‐II fluorescence imaging.

Recent Advances on NIR-II Light-Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) is a particular oncological therapeutic strategy by generates the highly toxic hydroxyl radical (•OH) from the dismutation of endogenous hydrogen peroxide (H2O2) via Fenton or Fenton-like reactions. However, single CDT therapies have been limited by unsatisfactory efficacy. Enhanced chemodynamic therapy (ECDT) triggered by near-infrared (NIR) is a novel therapeutic modality based on light energy to improve the efficiency of Fenton or Fenton-like reactions. However, the limited penetration and imaging capability of the visible (400-650 nm) and traditional NIR-I region (650-900 nm) light-amplified CDT restrict the prospects for its clinical application. Combined with the high penetration/high precision imaging characteristics of the second near-infrared (NIR-II,) nanoplatform, it is expected to kill deep tumors efficiently while imaging the treatment process in real-time, and more notably, the NIR-II region radiation with wavelengths above 1000 nm can minimize the irradiation damage to normal tissues. Such NIR-II ECDT nanoplatforms have greatly improved the effectiveness of CDT therapy and demonstrated extraordinary potential for clinical applications. Accordingly, various strategies have been explored in the past years to improve the efficiency of NIR-II Enhanced CDT. In this review, the mechanisms and strategies used to improve the performance of NIR-II-enhanced CDT are outlined.

Enzyme-Mediated Bioorthogonal Cascade Catalytic Reaction for Metabolism Intervention and Enhanced Ferroptosis on Neuroblastoma

It remains a tremendous challenge to explore effective therapeutic modalities against neuroblastoma, a lethal cancer of the sympathetic nervous system with poor prognosis and disappointing treatment outcomes. Considering the limitations of conventional treatment modalities and the intrinsic vulnerability of neuroblastoma, we herein develop a pioneering sequential catalytic therapeutic system that utilizes lactate oxidase (LOx)/horseradish peroxidase (HRP)-loaded amorphous zinc metal-organic framework, named LOx/HRP-aZIF, in combination with a 3-indole-acetic acid (IAA) prodrug. On the basis of abnormal lactate accumulation that occurs in the tumor microenvironment, the cascade reaction of LOx and HRP consumes endogenous glutathione and a reduced form of nicotinamide adenine dinucleotide to achieve the first stage of killing cancer cells via antioxidative incapacitation and electron transport chain interference. Furthermore, the generation of reactive oxygen species induced by HRP and IAA through bioorthogonal catalysis promotes ferritin degradation and lipid peroxidation, ultimately provoking self-enhanced ferroptosis with positive feedback by initiating an endogenous Fenton reaction. This work highlights the superiority of the natural enzyme-dependent cascade and bioorthogonal catalytic reaction, offering a paradigm for synergistically enzyme-based metabolism-ferroptosis anticancer therapy.

Hypoxia Reversion by Low-Immunogenic Ultra-Acid-Sensitive Comicelles of Protein-Polymer Conjugates Sensitizes Tumors to Photodynamic Therapy

Hypoxia is characteristic of the tumor microenvironment, which is correlated with resistance to photodynamic therapy (PDT), radiotherapy, chemotherapy, and immunotherapy. Catalase is potentially useful to catalyze the conversion of endogenous H2O2 to O2 for hypoxia reversion. However, the efficient delivery of catalase into the hypoxia regions of tumors is a huge challenge. Here, we report the self-assembly of ultra-acid-sensitive polymer conjugates of catalase and albumin into nanomicelles that are responsive to the acidic tumor microenvironment. The immunogenicity of catalase is mitigated by the presence of albumin, which reduces the cross-linking of catalase with B cell receptors, resulting in improved pharmacokinetics. The ultra acid sensitivity of the nanomicelles makes it possible to efficiently escape the lysosomal degradation after endocytosis and permeate into the interior of tumors to reverse hypoxia in vitro and in vivo. In mice bearing triple-negative breast cancer, the nanomicelles loaded with a photosensitizer effectively accumulate and penetrate into the whole tumors to generate a sufficient amount of O2 to reverse hypoxia, leading to enhanced efficacy of PDT without detectable side effects. These findings provide a general strategy of self-assembly to design low-immunogenic ultra-acid-sensitive comicelles of protein-polymer conjugates to reverse tumor hypoxia, which sensitizes tumors to PDT.

Dumbbell-shaped bimetallic AuPd nanoenzymes for NIR-II cascade catalysis-photothermal synergistic therapy

The noble metal NPs that are currently applied to photothermal therapy (PTT) have their photoexcitation location mainly in the NIR-I range, and the low tissue penetration limits their therapeutic effect. The complexity of the tumor microenvironment (TME) makes it difficult to inhibit tumor growth completely with a single therapy. Although TME has a high level of H2O2, the intratumor H2O2 content is still insufficient to catalyze the generation of sufficient hydroxide radicals (‧OH) to achieve satisfactory therapeutic effects. The AuPd-GOx-HA (APGH) was obtained from AuPd bimetallic nanodumbbells modified by glucose oxidase (GOx) and hyaluronic acid (HA) for photothermal enhancement of tumor starvation and cascade catalytic therapy in the NIR-II region. The CAT-like activity of AuPd alleviates tumor hypoxia by catalyzing the decomposition of H2O2 into O2. The GOx-mediated intratumoral glucose oxidation on the one hand can block the supply of energy and nutrients essential for tumor growth, leading to tumor starvation. On the other hand, the generated H2O2 can continuously supply local O2, which also exacerbates glucose depletion. The peroxidase-like activity of bimetallic AuPd can catalyze the production of toxic ‧OH radicals from H2O2, enabling cascade catalytic therapy. In addition, the high photothermal conversion efficiency (η = 50.7 %) of APGH nanosystems offers the possibility of photothermal imaging-guided photothermal therapy. The results of cell and animal experiments verified that APGH has good biosafety, tumor targeting, and anticancer effects, and is a precious metal nanotherapeutic system integrating glucose starvation therapy, nano enzyme cascade catalytic therapy, and PTT therapy. This study provides a strategy for photothermal-cascade catalytic synergistic therapy combining both exogenous and endogenous processes. STATEMENT OF SIGNIFICANCE: AuPd-GOx-HA cascade nanoenzymes were prepared as a potent cascade catalytic therapeutic agent, which enhanced glucose depletion, exacerbated tumor starvation and promoted cancer cell apoptosis by increasing ROS production through APGH-like POD activity. The designed system has promising photothermal conversion ability in the NIR-II region, simultaneously realizing photothermal-enhanced catalysis, PTT, and catalysis/PTT synergistic therapy both in vitro and in vivo. The present work provides an approach for designing and developing catalytic-photothermal therapies based on bimetallic nanoenzymatic cascades.

Biodegradable Metal Complex-Gated Organosilica for Dually Enhanced Chemodynamic Therapy through GSH Depletions and NIR Light-Triggered Photothermal Effects

Hollow silica spheres have been widely studied for drug delivery because of their excellent biosecurity and high porosity. However, difficulties with degradation in the tumor microenvironment (TME) and premature leaking during drug delivery limit their clinical applications. To alleviate these problems, herein, hollow organosilica spheres (HOS) were initially prepared using a "selective etching strategy" and loaded with a photothermal drug: new indocyanine green (IR820). Then, the Cu2+-tannic acid complex (Cu-TA) was deposited on the surface of the HOS, and a new nanoplatform named HOS@IR820@Cu-TA (HICT) was finally obtained. The deposition of Cu-TA can gate the pores of HOS completely to prevent the leakage of IR820 and significantly enhance the loading capacity of HOS. Once in the mildly acidic TME, the HOS and outer Cu-TA decompose quickly in response, resulting in the release of Cu2+ and IR820. The released Cu2+ can react with the endogenous glutathione (GSH) to consume it and produce Cu+, leading to the enhanced production of highly toxic ·OH through a Fenton-like reaction due to the overexpressed H2O2 in the TME. Meanwhile, the ·OH generation was remarkably enhanced by the NIR light-responsive photothermal effect of IR820. These collective properties of HICT enable it to be a smart nanomedicine for dually enhanced chemodynamic therapy through GSH depletions and NIR light-triggered photothermal effects.

Tunable Zeolitic Imidazolate Framework-8 Nanoparticles for Biomedical Applications

Zeolite imidazole framework-8 (ZIF-8) is the most prestigious one among zeolitic imidazolate framework (ZIF) with tunable dimensions and unique morphological features. Utilizing its synthetic adjustability and structural regularity, ZIF-8 exhibits enhanced flexibility, allowing for a wide range of functionalities, such as loading of nanoparticle components while preserving biomolecules activity. Extensive efforts are made from investigating synthesis techniques to develop novel applications over decades. In this review, the development and recent progress of various synthesis approaches are briefly summarized. In addition, its interesting properties such as adjustable porosity, excellent thermal, and chemical stabilities are introduced. Further, five representative biomedical applications are highlighted based on above physicochemical properties. Finally, the remaining challenges and offered insights into the future outlook are also discussed. This review aims to understand the co-relationships between structures and biomedical functionalities, offering the opportunity to construct attractive materials with promising characteristics.

Self-Driven Electric Field Control of Orbital Electrons in AuPd Alloy Nanoparticles for Cancer Catalytic Therapy

The free radical generation efficiency of nanozymes in cancer therapy is crucial, but current methods fall short. Alloy nanoparticles (ANs) hold promise for improving catalytic performance due to their inherent electronic effect, but there are limited ways to modulate this effect. Here, a self-driven electric field (E) system utilizing triboelectric nanogenerator (TENG) and AuPd ANs with glucose oxidase (GOx)-like, catalase (CAT)-like, and peroxidase (POD)-like activities is presented to enhance the treatment of 4T1 breast cancer in mice. The E stimulation from TENG enhances the orbital electrons of AuPd ANs, resulting in increased CAT-like, GOx-like, and POD-like activities. Meanwhile, the catalytic cascade reaction of AuPd ANs is further amplified after catalyzing the production of H2 O2 from the GOx-like activities. This leads to 89.5% tumor inhibition after treatment. The self-driven E strategy offers a new way to enhance electronic effects and improve cascade catalytic therapeutic performance of AuPd ANs in cancer therapy.

MOFs Modulate Copper Trafficking in Tumor Cells for Bioorthogonal Therapy

In situ drug synthesis using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has attracted considerable attention in tumor therapy because of its satisfactory effectiveness and reduced side-effects. However, the exogenous addition of copper catalysts can cause cytotoxicity and has hampered biomedical applications in vivo. Here, we design and synthesize a metal-organic framework (MOF) to mimic copper chaperone, which can selectively modulate copper trafficking for bioorthogonal synthesis with no need of exogenous addition of copper catalysts. Like copper chaperones, the prepared ZIF-8 copper chaperone mimics specifically bind copper ions through the formation of coordination bonds. Moreover, the copper is unloaded under the acidic environment due to the dissipation of the coordination interactions between metal ions and ligands. In this way, the cancer cell-targeted copper chaperone mimics can selectively transport copper ions into cells. Regulation of intracellular copper trafficking may inspire constructing bioorthogonal catalysis system with reduced metal cytotoxicity in live cells.

Macrophage-membrane-coated hybrid nanoparticles with self-supplied hydrogen peroxide for enhanced chemodynamic tumor therapy

Addressing the challenges of chemodynamic therapies (CDTs) relying on Fenton reactions in malignant tumors is an active research area. Here, we report a method to develop pH-responsive hybrid nanoparticles for enhanced chemodynamic tumor treatment. Reactive CaO2 nanoparticles (core) are isolated by biocompatible ZIF-8 doped with Fe2+ (shell), and then encapsulated by macrophage membranes (symbolized as CaO2@Fe-ZIF-8@macrophage membrane or CFZM), thus endowed with high stability under normal physiological conditions. Our design features active tumor-homing by the macrophage-membrane coating, tumor microenvironment (TME)-responsive cargo release, and self-supplied hydrogen peroxide for promotion of the Fenton reaction. We demonstrate the improved delivery/tumor cell uptake of CFZM, the efficient production of toxic ˙OH with self-supplied H2O2 in CFZM, and high-efficacy tumor ablation on BALB/c mice bearing CT26 tumor cells. This offers a translational strategy to develop active tumor-targeting and TME-responsive nanotherapeutics with enhanced CDT against malignant tumors.

A Purposefully Designed pH/GSH-Responsive MnFe-Based Metal-Organic Frameworks as Cascade Nanoreactor for Enhanced Chemo-Chemodynamic-Starvation Synergistic Therapy

Metal-organic frameworks (MOFs) have emerged as promising novel therapeutics for treating malignancies due to their tunable porosity, biocompatibility, and modularity to functionalize with various chemotherapeutics drugs. However, the design and synthesis of dual-stimuli responsive MOFs for controlled drug release in tumor microenvironments are vitally essential but still challenging. Meanwhile, the catalytic effect of metal ions selection and ratio optimization in MOFs for enhanced chemodynamic therapy (CDT) is relatively unexplored. Herein, a series of MnFe-based MOFs with pH/glutathione (GSH)-sensitivity are synthesized and then combined with gold nanoparticles (Au NPs) and cisplatin prodrugs (DSCP) as a cascade nanoreactor (SMnFeCGH) for chemo-chemodynamic-starvation synergistic therapy. H+ and GSH can specifically activate the optimal SMnFeCGH nanoparticles in cancer cells to release Mn2+/4+ /Fe2+/3+ , Au NPs, and DSCP rapidly. The optimal ratio of Mn/Fe shows excellent H2 O2 decomposition efficiency for accelerating CDT. Au NPs can cut off the energy supply to cancer cells for starvation therapy and strengthen CDT by providing large amounts of H2 O2 . Then H2 O2 is catalyzed by Mn2+ /Fe2+ to generate highly toxic •OH with the depletion of GSH. Meanwhile, the reduced DSCP accelerates cancer cell regression for chemotherapy. The ultrasensitivity cascade nanoreactor can enhance the anticancer therapeutic effect by combining chemotherapy, CDT, and starvation therapy.

Glucose oxidase-instructed biomineralization of calcium-based biomaterials for biomedical applications

In recent years, glucose oxidase (GOx) has aroused great research interest in the treatment of diseases related to abnormal glucose metabolisms like cancer and diabetes. However, as a kind of endogenous oxido-reductase, GOx suffers from poor stability and system toxicity in vivo. In order to overcome this bottleneck, GOx is encapsulated in calcium-based biomaterials (CaXs) such as calcium phosphate (CaP) and calcium carbonate (CaCO3) by using it as a biotemplate to simulate the natural biomineralization process. The biomineralized GOx holds improved stability and reduced side effects, due to the excellent bioactivity, biocompatibitliy, and biodegradability of CaXs. In this review, the state-of-the-art studies on GOx-mineralized CaXs are introduced with an emphasis on their application in various biomedical fields including disease diagnosis, cancer treatment, and diabetes management. The current challenges and future perspectives of GOx-mineralized CaXs are discussed, which is expected to promote further studies on these smart GOx-mineralized CaXs biomaterials for practical applications.

Biomimetic Construction of Degradable DNAzyme-Loaded Nanocapsules for Self-Sufficient Gene Therapy of Pulmonary Metastatic Breast Cancer

Pulmonary metastasis of breast cancer is the major cause of deaths of breast cancer patients, but the effective treatment of pulmonary metastases is still lacking at present. Herein, a degradable biomimetic DNAzyme biocapsule is developed with the poly(ethylenimine) (PEI)-DNAzyme complex encapsulated in a Mn2+/Zn2+-coordinated inositol hexaphosphate (IP6) capsule modified with the cRGD targeting peptide for high-efficiency gene therapy of both primary and pulmonary metastatic breast tumors. This DNAzyme biocapsule is degradable inside acidic lysosomes, leading to the release of DNAzyme and abundant Mn2+/Zn2+ for catalytic cleavage of EGR-1 mRNA. We find that PEI promotes the lysosomal escape of the released DNAzyme. Both in vitro and in vivo experiments demonstrate the apparent downregulation of EGR-1 and Bcl-2 protein expression after treatment with the DNAzyme biocapsule, thereby inducing apoptotic death of tumor cells. We further verify that the DNAzyme biocapsule exhibits potent therapeutic efficacy against both primary and pulmonary metastatic breast tumors with significant inhibition of peri-pulmonary metastasis. This study provides a promising effective strategy for constructing degradable DNAzyme-based platforms with self-supply of abundant metal ion cofactors for high-efficiency gene therapy of metastatic breast cancer.

pH-Responsive and Actively Targeted Metal-Organic Framework Structures for Multimodal Antitumor Therapy and Inhibition of Tumor Invasion and Metastasis

Multimodal treatment is an important tool to overcome tumor drug resistance. The reactive oxygen species (ROS) generated by photodynamic therapy (PDT) can directly play a killing role on tumor cells, which has the advantages of repeatable treatment and no drug resistance. However, its therapeutic oxygen consumption and destruction of tumor microvessels lead to hypoxia in tumor tissues, and hypoxia leads to overexpression of the receptor tyrosine kinase (c-MET) and vascular endothelial growth factor receptor (VEGFR). Overexpression of these two receptors leads to increased tumor invasiveness and metastasis. The molecularly targeted drug cabozantinib (CAB) has multiple targets, including anti-c-MET and VEGFR, to inhibit the development of hepatocellular carcinoma (HCC). In this study, our team designed a pH-sensitive nanoparticle CAB/Ce6@ZIF-8@PEG-FA (CCZP) loaded with CAB and Ce6, which exerted a multimodal therapeutic effect of PDT and molecularly targeted therapy by laser irradiation, and the PDT-induced overexpression of MET and VEGFR could also be inhibited by the target of CAB, thus reducing the invasive tumor cells metastasis. In summary, CCZP gives full play to the advantages of both drugs, exerting multimodal treatment while reducing HCC invasion and metastasis, providing a safe, potential approach to clinical treatment.

Liposomal Enzyme Nanoreactors Based on Nanoconfinement for Efficient Antitumor Therapy

Enzymatic reactions can consume endogenous nutrients of tumors and produce cytotoxic species and are therefore promising tools for treating malignant tumors. Inspired by nature where enzymes are compartmentalized in membranes to achieve high reaction efficiency and separate biological processes with the environment, we develop liposomal nanoreactors that can perform enzymatic cascade reactions in the aqueous nanoconfinement of liposomes. The nanoreactors effectively inhibited tumor growth in vivo by consuming tumor nutrients (glucose and oxygen) and producing highly cytotoxic hydroxyl radicals (⋅OH). Co-compartmentalization of glucose oxidase (GOx) and horseradish peroxidase (HRP) in liposomes could increase local concentration of the intermediate product hydrogen peroxide (H2 O2 ) as well as the acidity due to the generation of gluconic acid by GOx. Both H2 O2 and acidity accelerate the second-step reaction by HRP, hence improving the overall efficiency of the cascade reaction. The biomimetic compartmentalization of enzymatic tandem reactions in biocompatible liposomes provides a promising direction for developing catalytic nanomedicines in antitumor therapy.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

Self-Assembly Multivalent Fluorescence-Nanobody Coupled Multifunctional Nanomaterial with Colorimetric Fluorescence and Photothermal to Enhance Immunochromatographic Assay

The multimodal lateral flow immunoassay (LFIA) has provided accurate and reliable results for fast and immediate detection. Nonetheless, multimodal LFIA remains challenging to develop biosensors with high sensitivity and tolerance to matrix interference in agro-food. In this study, we developed a self-assembled multivalent fluorescence-nanobody (Nb26-EGFP-H6) with 16.5-fold and 30-fold higher affinity and sensitivity than a monovalent nanobody (Nb26). Based on the Nb26-EGFP-H6, we synthesized enhanced immune-probes Zn-CN@Nb26-EGFP-H6 by pyrolyzing and oxidizing an imidazolating zeolite framework-8 (ZIF-8) to obtain photothermal metal-carbon nanomaterials (Zn-CN) for immobilizing Nb26-EGFP-H6. The rough and porous structure of Zn-CN with a large surface area facilitates the enrichment and immobilization of antibodies. A trimodal lateral flow immunoassay (tLFIA) with colorimetric, fluorescent, and photothermal triple signal outputs was constructed for the detection of aflatoxin B1 (AFB1) in maize. Attractively, the Zn-CN-based tLFIA's multiplex guarantees accurate and sensitive detection of AFB1, with triple signal detection limits of 0.0012 ng/mL (colorimetric signals), 0.0094 ng/mL (fluorescent signals), and 0.252 ng/mL (photothermal signals). The sensitivity of the trimode immunosensor was 628-fold and 42-fold higher than that of the original Nb26-based ELISA (IC50) and the unimodal LFIA (LOD). This work provides an idea for constructing a sensitive, tolerant matrix and efficient and accurate analytical platform for rapidly detecting AFB1 in food.

Detachable MOF-Based Core/Shell Nanoreactor for Cancer Dual-Starvation Therapy With Reversing Glucose and Glutamine Metabolisms

Tumor-dependent glucose and glutamine metabolisms are essential for maintaining survival, while the accordingly metabolic suppressive therapy is limited by the compensatory metabolism and inefficient delivery efficiency. Herein, a functional metal-organic framework (MOF)-based nanosystem composed of the weakly acidic tumor microenvironment-activated detachable shell and reactive oxygen species (ROS)-responsive disassembled MOF nanoreactor core is designed to co-load glycolysis and glutamine metabolism inhibitors glucose oxidase (GOD) and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES) for tumor dual-starvation therapy. The nanosystem excitingly improves tumor penetration and cellular uptake efficiency via integrating the pH-responsive size reduction and charge reversal and ROS-sensitive MOF disintegration and drug release strategy. Furthermore, the degradation of MOF and cargoes release can be self-amplified via additional self-generation H2 O2 mediated by GOD. Last, the released GOD and BPTES collaboratively cut off the energy supply of tumors and induce significant mitochondrial damage and cell cycle arrest via simultaneous restriction of glycolysis and compensatory glutamine metabolism pathways, consequently realizing the remarkable triple negative breast cancer killing effect in vivo with good biosafety via the dual starvation therapy.

Opportunities and Challenges of Metal-Organic Framework Micro/Nano Reactors for Cascade Reactions

Building bridges among different types of catalysts to construct cascades is a highly worthwhile pursuit, such as chemo-, bio-, and chemo-bio cascade reactions. Cascade reactions can improve the reaction efficiency and selectivity while reducing steps of separation and purification, thereby promoting the development of "green chemistry". However, compatibility issues in cascade reactions pose significant constraints on the development of this field, particularly concerning the compatibility of diverse catalyst types, reaction conditions, and reaction rates. Metal-organic framework micro/nano reactors (MOF-MNRs) are porous crystalline materials formed by the self-assembly coordination of metal sites and organic ligands, possessing a periodic network structure. Due to the uniform pore size with the capability of controlling selective transfer of substances as well as protecting active substances and the organic-inorganic parts providing reactive microenvironment, MOF-MNRs have attracted significant attention in cascade reactions in recent years. In this Perspective, we first discuss how to address compatibility issues in cascade reactions using MOF-MNRs, including structural design and synthetic strategies. Then we summarize the research progress on MOF-MNRs in various cascade reactions. Finally, we analyze the challenges facing MOF-MNRs and potential breakthrough directions and opportunities for the future.

DNA-Templated Ag@Pd Nanoclusters for NIR-II Photoacoustic Imaging-Guided Photothermal-Augmented Nanocatalytic Therapy

Developing multifunctional nanozymes with photothermal-augmented enzyme-like reaction dynamics in the second near-infrared (NIR-II) biowindow is of significance for nanocatalytic therapy (NCT). Herein, DNA-templated Ag@Pd alloy nanoclusters (DNA-Ag@Pd NCs) are prepared as a kind of novel noble-metal alloy nanozymes by using cytosine-rich hairpin-shaped DNA structures as growth templates. DNA-Ag@Pd NCs exhibit high photothermal conversion efficiency (59.32%) under 1270 nm laser and photothermally augmented peroxidase-mimicking activity with synergetic enhancement between Ag and Pd. In addition, hairpin-shaped DNA structures on the surface of DNA-Ag@Pd NCs endow them with good stability and biocompatibility in vitro and in vivo, and enhanced permeability and retention effect at tumor sites. Upon intravenous injection, DNA-Ag@Pd NCs demonstrate high-contrast NIR-II photoacoustic imaging-guided efficient photothermal-augmented NCT of gastric cancer. This work provides a strategy to synthesize versatile noble-metal alloy nanozymes in a bioinspired way for highly efficient therapy of tumors.

A NIR-II Photoactivatable "ROS Bomb" with High-Density Cu2 O-Supported MoS2 Nanoflowers for Anticancer Therapy

The fast conversion of hydrogen peroxide (H2 O2 ) into reactive oxygen species (ROS) at tumor sites is a promising anticancer strategy by manipulating nanomedicines with near-infrared light in the second region (NIR-II). However, this strategy is greatly compromised by the powerful antioxidant capacity of tumors and the limited ROS generation rate of nanomedicines. This dilemma mainly stems from the lack of an effective synthesis method to support high-density copper-based nanocatalysts on the surface of photothermal nanomaterials. Herein, a multifunctional nanoplatform (MCPQZ) with high-density cuprous (Cu2 O) supported molybdenum disulfide (MoS2 ) nanoflowers (MC NFs) is developed for the efficient killing of tumors via a potent ROS storm by an innovative method. Under NIR-II light irradiation, the ROS intensity and maximum reaction velocity (Vmax ) produced by MC NFs are 21.6 and 33.8 times that of the non-irradiation group in vitro, which is much higher than most current nanomedicines. Moreover, the strong ROS storm in cancer cells is efficiently formed by MCPQZ (increased by 27.8 times compared to the control), thanks to the fact that MCPQZ effectively pre-weakens the multiple antioxidant systems of cancer cells. This work provides a novel insight to solve the bottleneck of ROS-based cancer therapy.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Recent advances in nanoscale metal-organic frameworks for cancer chemodynamic therapy

Chemodynamic therapy (CDT), a novel therapeutic approach based on Fenton (Fenton-like) reaction, has been widely employed for tumor therapy. This approach utilizes Fe, Cu, or other metal ions (Mn, Zn, Co, or Mo) to react with the excess hydrogen peroxide (H₂O₂) in tumor microenvironments (TME), and form highly cytotoxic hydroxyl radical (˙OH) to kill cancer cells. Recently, nanoscale metal-organic frameworks (nMOFs) have attracted considerable attention as promising CDT agents with the rapid development of cancer CDT. This review focuses on summarizing the latest advances (2020-2022) on the design of nMOFs as nanomedicine for CDT or combination therapy of CDT and other therapies. The future development and challenges of CDT are also proposed based on recent progress. Our group hopes that this review will enlighten the research and development of nMOFs for CDT.

Defect-Rich Ni-CoO@PEG Porous Hexagonal Nanosheets: Multi-enzyme and Ultrasound Catalysis for Synergistic Anticancer Treatment

Given the similarity with photocatalysis, sonodynamic therapy (SDT) can be defined as ultrasonic (US) catalysis. Encouraged by the principles of photocatalysis and defect chemistry, defect-rich nickel (Ni)-doped cobaltous oxide (Ni-CoO@PEG) porous hexagonal nanosheets have been synthesized as a sonosensitizer. The doping of Ni decreases the band gap that is testified by density functional theory to increase the US-generated charges. Under US irradiation, Ni-CoO@PEG nanosheets produce ¹O₂ as an active species that is determined by dissolved O₂ and electrons. Moreover, the doping also brings abundant oxygen vacancies (O_V) that not only are in favor of efficient separation of electron-hole but also enhance the interaction toward O₂, boosting ¹O₂ generation. In addition, Ni-CoO@PEG shows robust mimic catalase (CAT) and peroxidase characterization to effectively improve the intratumor O₂ content and oxidation stress. What is more, the nanosheets also possess glucose oxidase activity that can consume glucose to elevate the H₂O₂/acid level and to block the intracellular energy supply. The tandem nanozyme behaviors would further regulate the tumor microenvironment for assisting anticancer treatment. It is noted that Ni-CoO@PEG reveals a novel half-metallic feature endowing great magnetism and magnetic resonance imaging capacity. The above synergistic treatments exhibit outstanding anticancer performance that also evokes antitumor immunity to suppress metastasis and recurrence, efficiently.

Nanotechnological strategies to increase the oxygen content of the tumor

Hypoxia is a negative prognostic indicator of solid tumors, which not only changes the survival state of tumors and increases their invasiveness but also remarkably reduces the sensitivity of tumors to treatments such as radiotherapy, chemotherapy and photodynamic therapy. Thus, developing therapeutic strategies to alleviate tumor hypoxia has recently been considered an extremely valuable target in oncology. In this review, nanotechnological strategies to elevate oxygen levels in tumor therapy in recent years are summarized, including (I) improving the hypoxic tumor microenvironment, (II) oxygen delivery to hypoxic tumors, and (III) oxygen generation in hypoxic tumors. Finally, the challenges and prospects of these nanotechnological strategies for alleviating tumor hypoxia are presented.

In Situ Polymerization of Aniline Derivative in Vivo for NIR-II Phototheranostics of Tumor

Natural biopolymers can be controllably in situ synthesized in organisms and play important roles in biological activities. Inspired by this, the manipulation of in situ biosynthesis of functional polymers in vivo will be an important way to obtain materials for meeting biological requirements. Herein, in situ biosynthesis of functional conjugated polymer at the tumor site was achieved via the utilization of specific tumor microenvironment (TME) characteristics for the first time. Specially, a water-soluble aniline dimer derivative (N-(3-sulfopropyl) p-aminodiphenylamine, SPA) was artfully in situ polymerized into polySPA (PSPA) nanoparticles at the tumor site, which was activated via the catalysis of hydrogen peroxide (H2O2) overexpressed in TME to produce hydroxyl radical (•OH) by coinjected horseradish peroxidase (HRP). Benefiting from outstanding near-infrared (NIR)-II absorption of PSPA, the in situ polymerization process can be validly monitored by photoacoustic (PA) signal at the NIR-II region. Meanwhile, in situ polymerization would induce the size of polymeric materials from small to large, improving the distribution and retention of PSPA at the tumor site. On the combination of NIR-II absorption of PSPA and the size variation induced by polymerization, such polymerization can be applied for tumor-specific NIR-II light mediated PA image and photothermal inhibition of tumors, enhancing the precision and efficacy of tumor phototheranostics. Therefore, the present work opens the way to manipulate TME-activated in situ biosynthesis of functional conjugated polymer at the tumor site for overcoming formidable challenges in tumor theranostics.