A Catalase-Like Metal-Organic Framework Nanohybrid for O2 -Evolving Synergistic Chemoradiotherapy

Near-infrared light-triggered β-NaYF4:Yb,Tm,Gd@MIL-100(Fe) nanomaterials for antibacterial applications

By inducing a photo-Fenton reaction under 980 nm light irradiation, β-NaYF4:Yb,Tm,Gd@MIL-100(Fe) could generate abundant ROS for antibacterial applications.

Chiral nanomaterials for biosensing, bioimaging, and disease therapies

Chiral plasmonic nanomaterials for biosensing, bioimaging and disease therapy.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.

Oxygen switches: Refueling for cancer radiotherapy

Radiotherapy remains the major therapeutic intervention for tumor patients. However, the hypoxic tumor microenvironment leads to treatment resistance. Recently, a burgeoning number of nano-radiosensitizers designed to increase the oxygen concentration in tumors were reported. These nano radiosensitizers served as oxygen carriers, oxygen generators, and even sustained oxygen pumps, attracting increased research interest. In this review, we focus on the novel oxygen-enrich nano radiosensitizers, which we call oxygen switches, and highlight their influence in radiotherapy through different strategies. Physical strategies-based oxygen switches carried O₂ into the tumor via their high oxygen capacity. The chemical reactions to generate O₂ in situ were triggered by chemical strategies-based oxygen switches. Biological strategies-based oxygen switches regulated tumor metabolism, remodeled tumor vasculature, and even introduced microorganisms-mediated photosynthesis for long-lasting hypoxia alleviating. Moreover, the challenges and perspectives of oxygen switches-mediated oxygen-enrich radiotherapy were discussed.

Recent advances in the protective role of metallic nanoparticles in red blood cells

The interaction of nanoparticles with the biological system has increased with the increasing popularity of nanomedicines. Red blood cells (RBCs) are very sensitive, and abundant cells in the blood. They are highly prone to oxidative damage due to constant interaction with oxygen itself, foreign particles in the blood, and the lack of repair mechanism. The cell membrane of RBCs undergoes lipid peroxidation, protein oxidation, and heme degradation which results in altered membrane permeability, changes in the morphology, and functioning of RBCs. The nanoparticles induce oxidative stress, hemolysis, morphological changes, membrane deformability, and alterations in hemoglobin structure in RBCs. In this review, the effects of metallic nanoparticles and their modifications on the physiology, and life span of RBCs are discussed. The detailed analysis of the antioxidant enzymes-like activity of metal nanoparticles is expected to highlight the beneficial use of these metal nanoparticles in RBCs against oxidative stress and the development of new biosafe nanodrugs.

Dynamic nano-assemblies based on two-dimensional inorganic nanoparticles: Construction and preclinical demonstration

Dynamic drug delivery systems (DDSs) have the ability of transforming their morphology and functionality in response to the biological microenvironments at the disease site and/or external stimuli, show spatio-temporally controllable drug delivery, and enhance the treatment efficacy. Due to the large surface area and modification flexibility, two-dimensional (2D) inorganic nanomaterials are being increasingly exploited for developing intelligent DDSs for biomedical applications. In this review, we summarize the engineering methodologies used to construct transformable 2D DDSs, including changing compositions, creating defects, and surface dot-coating with polymers, biomolecules, or nanodots. Then we present and discuss dynamic inorganic 2D DDSs whose transformation is driven by the diseased characteristics, such as pH gradient, redox, hypoxia, and enzyme in the tumor microenvironment as well as the external stimuli including light, magnetism, and ultrasound. Finally, the limitations and challenges of current transformable inorganic DDSs for clinical translation and their in vivo safety assessment are discussed.

Emissive oxidase-like nanozyme based on an organic molecular cage

In this study, we introduced four "claw-like" units of dipicolylamine (DPA) to a tetraphenylethylene (TPE)-based organic molecular cage (DPA-TPE-Cage). Coordinated with Zn²⁺ ions, the obtained ZnDPA-TPE-Cage exhibited aggregation induced emission (AIE) effects and oxidase-like properties, which endowed it with the ability to selectively image and kill Gram-positive bacteria S. aureus efficiently.

Advances of Nanomedicine in Radiotherapy

Radiotherapy (RT) remains one of the current main treatment strategies for many types of cancer. However, how to improve RT efficiency while reducing its side effects is still a large challenge to be overcome. Advancements in nanomedicine have provided many effective approaches for radiosensitization. Metal nanoparticles (NPs) such as platinum-based or hafnium-based NPs are proved to be ideal radiosensitizers because of their unique physicochemical properties and high X-ray absorption efficiency. With nanoparticles, such as liposomes, bovine serum albumin, and polymers, the radiosensitizing drugs can be promoted to reach the tumor sites, thereby enhancing anti-tumor responses. Nowadays, the combination of some NPs and RT have been applied to clinical treatment for many types of cancer, including breast cancer. Here, as well as reviewing recent studies on radiotherapy combined with inorganic, organic, and biomimetic nanomaterials for oncology, we analyzed the underlying mechanisms of NPs radiosensitization, which may contribute to exploring new directions for the clinical translation of nanoparticle-based radiosensitizers.

Site-Selective Photosynthesis of Ag-AgCl@Au Nanomushrooms for NIR-II Light-Driven O2- and O2•--Evolving Synergistic Photothermal Therapy against Deep Hypoxic Tumors

Light-driven endogenous water oxidation has been considered as an attractive and desirable way to obtain O2 and reactive oxygen species (ROS) in the hypoxic tumor microenvironment. However, the use of a second near-infrared (NIR-II) light to achieve endogenous H2O oxidation to alleviate tumor hypoxia and realize deep hypoxic tumor phototherapy is still a challenge. Herein, novel plasmonic Ag-AgCl@Au core-shell nanomushrooms (NMs) were synthesized by the selective photodeposition of plasmonic Au at the bulge sites of the Ag-AgCl nanocubes (NCs) under visible light irradiation. Upon NIR-II light irradiation, the resulting Ag-AgCl@Au NMs could oxidize endogenous H2O to produce O2 to alleviate tumor hypoxia. Almost synchronously, O2 could react with electrons on the conduction band of the AgCl core to generate superoxide radicals (O2•-)for photodynamic therapy. Moreover, Ag-AgCl@Au NMs with an excellent photothermal performance could further promote the phototherapy effect. In vitro and in vivo experimental results show that the resulting Ag-AgCl@Au NMs could significantly improve tumor hypoxia and enhance phototherapy against a hypoxic tumor. The present study provides a new strategy to design H2O-activatable, O2- and ROS-evolving NIR II light-response nanoagents for the highly efficient and synergistic treatment of deep O2-deprived tumor tissue.

Structural diversity of nanoscale zirconium porphyrin MOFs and their photoactivities and biological performances

Photoactive MOF-based delivery systems are highly attractive for photodynamic therapy (PDT), but the fundamental interplay among structural parameters and photoactivity and biological properties of these MOFs remains unclear. Herein, porphyrinic MOF isomers (TCPP-MOFs), constructing using the same building blocks into distinct topologies, have been selected as ideal models to understand this problem. Both the intramolecular distances and molecular polarization within TCPP-MOFs isomers collectively contribute to the photoactivity of generating reactive oxygen species. Remarkably, the morphology-determined endocytic pathways and cytotoxicity, as well as good biocompatibility have been confirmed for TCPP-MOF isomers without any chemical modification for the first time. Besides the topology-dependent photoactive regulation, this work also provides in-depth insights into the biological effect from the MOF nanoparticles with controllable structural factors, benefiting further in vivo applications and clinical transformation.

Biodegradable Metal Organic Frameworks for Multimodal Imaging and Targeting Theranostics

Though there already had been notable progress in developing efficient therapeutic strategies for cancers, there still exist many requirements for significant improvement of the safety and efficiency of targeting cancer treatment. Thus, the rational design of a fully biodegradable and synergistic bioimaging and therapy system is of great significance. Metal organic framework (MOF) is an emerging class of coordination materials formed from metal ion/ion clusters nodes and organic ligand linkers. It arouses increasing interest in various areas in recent years. The unique features of adjustable composition, porous and directional structure, high specific surface areas, biocompatibility, and biodegradability make it possible for MOFs to be utilized as nano-drugs or/and nanocarriers for multimodal imaging and therapy. This review outlines recent advances in developing MOFs for multimodal treatment of cancer and discusses the prospects and challenges ahead.

Nanoscale metal-organic frameworks for tumor phototherapy

Metal-Organic Frameworks (MOFs) are constructed from metal ions/cluster nodes and functional organic ligands through coordination bonds. Owing to the advantages of diverse synthetic methods, easy modification after synthesis, large adsorption capacity for heavy metals, and short equilibrium time, considerable attention has recently been paid to MOFs for tumor phototherapy. Through rational tuning of metal ions and ligands, MOFs present abundant properties for various applications. Light-triggered phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is an emerging cancer treatment approach. Nanosized MOFs can be applied as phototherapeutic agents to accomplish phototherapy with excellent phototherapeutic efficacy. This review outlines the latest advances in the field of phototherapy with various metal ion-based MOFs.

Phosphate-Degradable Nanoparticles Based on Metal-Organic Frameworks for Chemo-Starvation-Chemodynamic Synergistic Antitumor Therapy

Chemodynamic therapy (CDT) was regarded as a promising approach for tumor treatment. However, owing to the insufficient amount of endogenous hydrogen peroxide (H2O2) in tumor cells, the efficacy of CDT was limited. In this study, we designed phosphate-responsive nanoparticles (denoted as MGDFT NPs) based on metal-organic frameworks, which were simultaneously loaded with drug doxorubicin (DOX) and glucose oxidases (GOx). The decorated GOx could act as a catalytic nanomedicine for the response to the abundant glucose in the tumor microenvironment, generating a great deal of H2O2, which would enhance the Fenton reaction and produce toxic hydroxyl radicals (·OH). Meanwhile, the growth of tumors would also be inhibited by overconsuming the intratumoral glucose, which was the "fuel" for cell proliferation. When the nanoparticles entered into tumor cells, a high concentration of phosphate induced structure collapse, releasing the loaded DOX for chemotherapy. Furthermore, the decoration of target agents endowed the nanoparticles with favorable target ability to specific tumor cells and mitochondria. Consequently, the designed MGDFT NPs displayed desirable synergistic therapeutic effects via combining chemotherapy, starvation therapy, and enhanced Fenton reaction, facilitating the development of multimodal precise antitumor therapy.

Electrochemical aptasensor based on gold modified thiol graphene as sensing platform and gold-palladium modified zirconium metal-organic frameworks nanozyme as signal enhancer for ultrasensitive detection of mercury ions

Gold modified thiol graphene (Au@HS-rGO) was prepared and applied as sensing platform for constructing the electrochemical aptasensor. While gold-palladium modified zirconium metal-organic frameworks (AuPd@UiO-67) nanozyme was employed as signal enhancer for detecting mercury ions (Hg²⁺) sensitively. Herein, gold nanoparticles (Au NPs) were modified on HS-rGO to form the thin Au@HS-rGO layer. Then the substrate strand (Apt1) was modified on the platform through Au-S bond. The signal strand (Apt2) was further decorated on the platform in the presence of Hg²⁺. Herein, the Apt2 was labeled with AuPd@UiO-67 nanozyme, which exhibited catalase-like properties to catalyze H₂O₂, thereby generating the electrical signal. With the concentration of Hg²⁺ increased, the amount of modified Apt2-AuPd@UiO-67 increased, leading to the rise of current response. Since the current responses were linear with concentration of Hg²⁺, the detection of Hg²⁺ can be achieved. Under the optimum conditions, the prepared electrochemical aptasensor exhibited wide linear range from 1.0 nmol/L to 1.0 mmol/L, along with a low detection limit of 0.16 nmol/L. Moreover, the electrochemical aptasensor showed excellent selectivity, reproducibility and stability, together with superior performance in actual water sample analysis. Therefore, this proposed electrochemical aptasensor may have promising applications and provide references for environmental monitoring and management.

Beyond Photo: Xdynamic Therapies in Fighting Cancer

Reactive oxygen species (ROS)-related therapeutic approaches are developed as a promising modality for cancer treatment because the aberrant increase of intracellular ROS level can cause cell death due to nonspecific oxidation damage to key cellular biomolecules. However, the most widely considered strategy, photodynamic therapy (PDT), suffers from critical limitations such as limited tissue-penetration depth, high oxygen dependence, and phototoxicity. Non-photo-induced ROS generation strategies, which are defined as Xdynamic therapies (X = sono, radio, microwave, chemo, thermo, and electro), show good potential to overcome the drawbacks of PDT. Herein, recent advances in the development of Xdynamic therapies, including the design of systems, the working mechanisms, and examples of cancer therapy application, are introduced. Furthermore, the approaches to enhance treatment efficiency of Xdynamic therapy are highlighted. Finally, the perspectives and challenges of these strategies are also discussed.

Rational design of type I photosensitizers based on Ru(ii) complexes for effective photodynamic therapy under hypoxia

Photodynamic therapy (PDT) has been widely used in conjunction with molecular oxygen to cause cancer cell death. Hypoxia, the inherent property in solid tumors, is the obstacle during the process of PDT. It is urgent to develop PDT photosensitizers independent of the oxygen concentration. Herein, triphenylamine-modified Ru(ii) complexes have been used as photosensitizers to produce superoxide anions (O2-˙) and hydroxyl radicals (˙OH) through a type I photochemical process. Ru(ii) complexes with triphenylamine can provide a possibility to drive the reactive oxygen species production through low oxidation potential and good light-harvesting abilities. The investigation on light-mediated radical production showed that Ru4 could produce abundant ˙OH and O2-˙ compared to Ru1-Ru3 under hypoxic environments owing to the strong absorption. These radicals exhibit potent toxicity, which can damage the neighbouring biomolecules and cause the apoptosis of cancer cells. The PDT effect was evaluated in vitro under hypoxia, suggesting that Ru4 could maintain excellent performance in inducing a sharp decrease in the activity of cancer cells.

In Vivo X-ray Triggered Catalysis of H2 Generation for Cancer Synergistic Gas Radiotherapy

To date, hydrogen (H₂ ) therapy has received widespread attention. However, X-ray triggered sustainable H₂ -producing materials with controlled release for cancer treatment have not been reported. Herein, an X-ray triggered sustainable in situ H₂ producing platform, Au NR-TiO₂ @ZnS:Cu,Co-A(Au-TiO₂ @ZnS), composed of Au-amorphous TiO₂ nano-dumbbell-shaped heterostructure coated with long afterglow particles, was developed for cancer synergistic H₂ -radiotherapy. The mechanism of H₂ production was verified by theoretical calculations and in vitro experiments. Changes in the apoptosis pathway caused by the synergistic effect of H₂ and radiotherapy were reported. Guided by its excellent photoacoustic imaging capabilities, mice with orthotopic liver cancer achieved excellent therapeutic effects and low inflammatory side effects, suggesting that Au-TiO₂ @ZnS has promising application potential for cancer treatment and prognosis.

Photodynamic-Chemodynamic Cascade Reactions for Efficient Drug Delivery and Enhanced Combination Therapy

Nanomedicines with photodynamic therapy and reactive oxygen species (ROS)-triggered drug release capabilities are promising for cancer therapy. However, most of the nanomedicines based on ROS-responsive nanocarriers still suffer from serious ROS consumption during the triggered drug release process. Herein, a photodynamic-chemodynamic cascade strategy for the design of drug delivery nanosystem is proposed. A doxorubicin hydrochloride-loaded ROS-responsive polymersome (DOX-RPS) is prepared via the self-assembly of amphiphilic poly(ethylene glycol)-poly(linoleic acid) and poly(ethylene glycol)-(2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-α)-iron chelate (PEG-HPPH-Fe). The RPS can effectively deliver a drug to tumor site through passive targeting effect. Upon laser irradiation, the photosensitizer HPPH can efficiently generate ROS, which further causes in situ oxidation of linoleic acid chain and subsequent RPS structural destruction, permitting triggered drug release. Intriguingly, catalyzed by HPPH-Fe, ROS will be regenerated from linoleic acid peroxide through a chemodynamic process. Therefore, ROS-triggered drug release can be achieved without ROS over-consumption. The in vitro and in vivo results confirmed ROS generation, triggered drug release behavior, and potent antitumor effect of the DOX-RPS. This photodynamic-chemodynamic cascade strategy provides a promising approach for enhanced combination therapy.

Smart biomimetic metal organic frameworks based on ROS-ferroptosis-glycolysis regulation for enhanced tumor chemo-immunotherapy

Antitumor immunotherapy is limited by low tumor immunogenicity and immunosuppressive microenvironment (TIME), which could be improved by "ROS-ferroptosis-glycolysis regulation" strategy. Herein, a cancer cell membrane coated metal organic framework (MOF) loading with glucose oxidase (GOx) and doxorubicin (DOX) was constructed (denoted as mFe(SS)/DG). Benefiting from the homotypic targeting of cancer cell membrane, the nanoplatform effectively accumulated in tumors. mFe(SS)/DG based on coordination between Fe³⁺ and disulfide-bearing ligand scavenged GSH and downregulated glutathione peroxide 4 (GPX4) to trigger ferroptosis. GOx catalyzed glucose to generate abundant H₂O₂ for enhancing Fenton reaction, resulting in excessive ROS in tumors. The ROS burst simultaneously promoted ferroptosis and inhibited glycolysis. Ferroptosis combined with DOX induced immunogenic cell death (ICD) and released tumor antigens to initiate antitumor immunity. Glycolysis repression remodeled TIME by decreasing lactate to solidify and boost the antitumor immunity. The smart biomimetic nanoplatform integrates tumor metabolism and immunity based on ROS-ferroptosis-glycolysis regulation, providing a potential anti-tumor strategy.

A multifunctional Fenton nanoagent for microenvironment-selective anti-biofilm and anti-inflammatory therapy

Bacterial biofilm infections are intractable to traditional antibiotic treatment and usually cause persistent inflammation. Chemodynamic therapy (CDT) based on the Fenton reaction has recently emerged as a promising anti-biofilm strategy. However, the therapeutic efficacy of current Fenton agents often suffers from inefficient Fenton activity and lacks anti-inflammatory capability. Herein, FePS₃ nanosheets (NSs) are explored for the first time as novel microenvironment-selective therapeutic nanoagents for bacterial biofilm infections with both self-enhanced Fenton activity for an anti-biofilm effect and reactive oxygen species (ROS) scavenging properties for an anti-inflammatory effect. In biofilms with acidic microenvironments, FePS₃ NSs release Fe²⁺ to generate toxic ROS by Fenton reaction and reductive [P₂S₆]^4- to enhance the Fenton activity by reducing Fe³⁺ to Fe²⁺. In the surrounding normal tissues with neutral pH, FePS₃ NSs scavenge ROS by reductive [P₂S₆]^4- with an anti-inflammatory effect. This work demonstrates multifunctional Fenton nanoagents with microenvironment-selective ROS generation and elimination properties for effective treatment of bacterial biofilm infections with both anti-biofilm and anti-inflammatory effects.

Metal-ligand coordination nanomaterials for radiotherapy: emerging synergistic cancer therapy

Radiotherapy (RT) plays a central role in curing malignant tumors. However, the treatment outcome is often impeded by low radiation absorption coefficients and radiation resistance of tumors along with normal tissue radio-toxicity. With the development of nanotechnology, nanomaterials in combination with RT offer the possibility to improve the therapeutic efficacy yet reduce side-effects. Metal-ligand coordination nanomaterials, including nanoscale metal-organic frameworks (NMOFs) and nanoscale coordination polymers (NCPs), formed by coordination interactions between inorganic metal ions/clusters with organic bridging ligands, have shown great potential in the field of radiation oncology in recent years in view of their unique advantages including the porous structure, high surface area, periodic frameworks, and diverse selections of both metal ions/clusters and organic ligands. In this review, we summarize the recent advances in NMOF/NCP-mediated synergistic RT in combination with hypoxia relief, chemotherapy, photodynamic therapy, photothermal therapy, chemodynamic therapy or immunotherapy, which emerged in the last 3 years, and describe cooperative enhancement interactions among these synergistic combinations. Moreover, the potential challenges and future prospects of this rapidly growing direction were also addressed.

Nanomaterials for Tumor Hypoxia Relief to Improve the Efficacy of ROS-Generated Cancer Therapy

Given the fact that excessive levels of reactive oxygen species (ROS) induce damage to proteins, lipids, and DNA, various ROS-generating agents and strategies have been explored to induce cell death and tumor destruction by generating ROS above toxic threshold. Unfortunately, hypoxia in tumor microenvironment (TME) not only promotes tumor metastasis but also enhances tumor resistance to the ROS-generated cancer therapies, thus leading to ineffective therapeutic outcomes. A variety of nanotechnology-based approaches that generate or release O2 continuously to overcome hypoxia in TME have showed promising results to improve the efficacy of ROS-generated cancer therapy. In this minireview, we present an overview of current nanomaterial-based strategies for advanced cancer therapy by modulating the hypoxia in the TME and promoting ROS generation. Particular emphasis is put on the O2 supply capability and mechanism of these nanoplatforms. Future challenges and opportunities of design consideration are also discussed. We believe that this review may provide some useful inspiration for the design and construction of other advanced nanomaterials with O2 supply ability for overcoming the tumor hypoxia-associated resistance of ROS-mediated cancer therapy and thus promoting ROS-generated cancer therapeutics.

Designing Hypoxia-Responsive Nanotheranostic Agents for Tumor Imaging and Therapy

Hypoxia, a common feature of most solid tumors, plays an important role in tumor proliferation, metastasis, and invasion, leading to drug, radiation, and photodynamic therapy resistance, and resulting in a sharp reduction in the disease-free survival rate of tumor patients. The lack of sufficient blood supply to the interior regions of tumors hinders the delivery of traditional drugs and contrast agents, interfering with their accumulation in the hypoxic region, and preventing efficient theranostics. Thus, there is a need for the fabrication of novel tumor theranostic agents that overcome these obstacles. Reports, in recent years, of hypoxia-responsive nanomaterials may provide with such means. In this review, a comprehensive description of the physicochemical and biological characteristics of hypoxic tumor tissues is provided, the principles of designing the hypoxia-responsive tumor theranostic agents are discussed, and the recent research into hypoxia-triggered nanomaterials is examined. Additionally, other hypoxia-associated responsive strategies, the current limitations, and future prospects for hypoxia-responsive nanotheranostic agents in tumor treatment are discussed.

Supramolecular metal-based nanoparticles for drug delivery and cancer therapy

Although conventional cancer therapies such as chemotherapy and radiotherapy prevail in clinic, they tend to have narrow therapeutic windows. Many chemotherapies have unfavorable pharmacokinetics while radiotherapy incurs radiotoxicity to normal tissues surrounding tumors. The chemical tunability of supramolecular metal-based nanoparticles (SMNPs) enables the incorporation of various therapeutics, including hydrophilic and hydrophobic chemotherapeutic drugs, photosensitizers, radiosensitizers, and biological therapeutics for more effective delivery to tumors. In this mini-review, we highlight recent advances in SMNPs, namely nanoscale coordination polymers and nanoscale metal-organic frameworks, for drug delivery and cancer therapy. We particularly focus on innovative uses of metal clusters, ligands, pores, and surface modifications to load various therapeutics into SMNPs and critical evaluations of the anticancer efficacies of SMNPs.

Tumor Microenvironment-Responsive Nanococktails for Synergistic Enhancement of Cancer Treatment via Cascade Reactions

A combination treatment strategy that relies on the synergetic effects of different therapeutic approaches has been considered to be an effective method for cancer therapy. Herein, a chemotherapeutic drug (doxorubicin, Dox) and a manganese ion (Mn²⁺) were co-loaded into regenerated silk fibroin-based nanoparticles (NPs), followed by the surface conjugation of phycocyanin (PC) to construct tumor microenvironment-activated nanococktails. The resultant PC-Mn@Dox-NPs showed increased drug release rates by responding to various stimulating factors (acidic pH, hydrogen peroxide (H₂O₂), and glutathione), revealing that they could efficiently release the payloads (Dox and Mn²⁺) in tumor cells. The released Dox could not only inhibit the growth of tumor cells but also generated a large amount of H₂O₂. The elevated H₂O₂ was decomposed into the highly harmful hydroxyl radicals and oxygen through an Mn²⁺-mediated Fenton-like reaction. Furthermore, the generated oxygen participated in photodynamic therapy (PDT) and produced abundant singlet oxygen. Our investigations demonstrate that these PC-Mn@Dox-NPs exhibit multiple bioresponsibilities and favorable biosafety. By integrating Dox-induced chemotherapy, Mn²⁺-mediated chemodynamic therapy, and PC-based PDT via cascade reactions, PC-Mn@Dox-NPs achieved enhanced in vitro and in vivo anticancer efficacies compared to all the mono- or dual-therapeutic approaches. These findings reveal that PC-Mn@Dox-NPs can be exploited as a promising nanococktail for cascade reaction-mediated synergistic cancer treatment.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Transfer hydrogenation catalysis in cells

Hydrogenation reactions in biology are usually carried out by enzymes with nicotinamide adenine dinucleotide (NAD(P)H) or flavin mononucleotide (FAMH2)/flavinadenine dinucleotide (FADH2) as cofactors and hydride sources. Industrial scale chemical transfer hydrogenation uses small molecules such as formic acid or alcohols (e.g. propanol) as hydride sources and transition metal complexes as catalysts. We focus here on organometallic half-sandwich RuII and OsII η6-arene complexes and RhIII and IrIII η5-Cp x complexes which catalyse hydrogenation of biomolecules such as pyruvate and quinones in aqueous media, and generate biologically important species such as H2 and H2O2. Organometallic catalysts can achieve enantioselectivity, and moreover can be active in living cells, which is surprising on account of the variety of poisons present. Such catalysts can induce reductive stress using formate as hydride source or oxidative stress by accepting hydride from NAD(P)H. In some cases, photocatalytic redox reactions can be induced by light absorption at metal or flavin centres. These artificial transformations can interfere in biochemical pathways in unusual ways, and are the basis for the design of metallodrugs with novel mechanisms of action.

Calcium phosphate engineered photosynthetic microalgae to combat hypoxic-tumor by in-situ modulating hypoxia and cascade radio-phototherapy

Rationale: Hypoxia is one of the crucial restrictions in cancer radiotherapy (RT), which leads to the hypoxia-associated radioresistance of tumor cells and may result in the sharp decline in therapeutic efficacy. Methods: Herein, living photosynthetic microalgae (Chlorella vulgaris, C. vulgaris), were used as oxygenators, for in situ oxygen generation to relieve tumor hypoxia. We engineered the surface of C. vulgaris (CV) cells with calcium phosphate (CaP) shell by biomineralization, to form a biomimetic system (CV@CaP) for efficient tumor delivery and in-situ active photosynthetic oxygenation reaction in tumor. Results: After intravenous injection into tumor-bearing mice, CV@CaP could remarkably alleviate tumor hypoxia by continuous oxygen generation, thereby achieving enhanced radiotherapeutic effect. Furthermore, a cascade phototherapy could be fulfilled by the chlorophyll released from photosynthetic microalgae combined thermal effects under 650 nm laser irradiation. The feasibility of CV@CaP-mediated combinational treatment was finally validated in an orthotropic breast cancer mouse model, revealing its prominent anti-tumor and anti-metastasis efficacy in hypoxic-tumor management. More importantly, the engineered photosynthetic microalgae exhibited excellent fluorescence and photoacoustic imaging properties, allowing the self-monitoring of tumor therapy and tumor microenvironment. Conclusions: Our studies of this photosynthetic microsystem open up a new dimension for solving the radioresistance issue of hypoxic tumors.

Recent advances in nanosized metal organic frameworks for drug delivery and tumor therapy

Metal organic-frameworks (MOFs) are novel materials that have attracted increasing attention for applications in a wide range of research, owing to their unique advantages including their small particle size, porous framework structure and high specific surface area. Because of their adjustable size, nanoscale MOFs (nano-MOFs) can be prepared as carriers of biotherapy drugs, thus enabling biotherapeutic applications. Nano-MOFs' metal ion catalytic activity and organic group functional characteristics can be exploited in biological treatments. Furthermore, the applications of nano-MOFs can be broadened by hybridization with other materials to form composites. This review focuses on the preparation and recent advances in nano-MOFs as drug carriers, therapeutic materials and functionalized materials in drug delivery and tumor therapy based on the single/multiple stimulus response of drug release to achieve the targeted therapy, offering a comprehensive reference for drug carrier design. At the end, the current challenges and prospects are discussed to provide significant insight into the design and applications of nano-MOFs in drug delivery and tumor therapy.

Multifunctional metal-organic framework heterostructures for enhanced cancer therapy

Metal-organic frameworks (MOFs) are an emerging class of molecular crystalline materials built from metal ions or clusters bridged by organic linkers. By taking advantage of their synthetic tunability and structural regularity, MOFs can hierarchically integrate nanoparticles and/or biomolecules into a single framework to enable multifunctions. The MOF-protected heterostructures not only enhance the catalytic capacity of nanoparticle components but also retain the biological activity of biomolecules in an intracellular microenvironment. Therefore, the multifunctional MOF heterostructures have great advantages over single components in cancer therapy. In this review, we comprehensively summarize the general principle of the design and functional modulation of nanoscaled MOF heterostructures, and biomedical applications in enhanced therapy within the last five years. The functions of MOF heterostructures with a controlled size can be regulated by designing various functional ligands and in situ growth/postmodification of nanoparticles and/or biomolecules. The advances in the application of multifunctional MOF heterostructures are also explored for enhanced cancer therapies involving photodynamic therapy, photothermal therapy, chemotherapy, radiotherapy, immunotherapy, and theranostics. The remaining challenges and future opportunities in this field, in terms of precisely localized assembly, maximizing composite properties, and processing new techniques, are also presented. The introduction of multiple components into one crystalline MOF provides a promising approach to design all-in-one theranostics in clinical treatments.

Tumor Microenvironment-Responsive Fe(III)-Porphyrin Nanotheranostics for Tumor Imaging and Targeted Chemodynamic-Photodynamic Therapy

The development of effective and safe tumor nanotheranostics remains a research imperative. Herein, tumor microenvironment (TME)-responsive Fe(III)-porphyrin (TCPP) coordination nanoparticles (FT@HA NPs) were prepared using a simple one-pot method followed by modification with hyaluronic acid (HA). FT@HA NPs specifically accumulated in CD44 receptor-overexpressed tumor tissues through the targeting property of HA and upon endocytosis by tumor cells. After cell internalization, intracellular acidic microenvironments and high levels of glutathione (GSH) triggered the rapid decomposition of FT@HA NPs to release free TCPP molecules and Fe(III) ions. The released Fe(III) ions could trigger GSH depletion and Fenton reaction, activating chemodynamic therapy (CDT). Meanwhile, the fluorescence and photodynamic effects of the TCPP could be also activated, achieving controlled reactive oxygen species (ROS) generation and avoiding side effects on normal tissues. Moreover, the rapid consumption of GSH further enhanced the efficacy of CDT and photodynamic therapy (PDT). The in vivo experiments further demonstrated that the antitumor effect of these nanotheranostics was significantly enhanced and that their toxicity and side effects against normal tissues were effectively suppressed. The FT@HA NPs can be applied for activated tumor combination therapy under the guidance of dual-mode imaging including fluorescence imaging and magnetic resonance imaging, providing an effective strategy for the design and preparation of TME-responsive multifunctional nanotheranostics for precise tumor imaging and combination therapy.

Retooling Cancer Nanotherapeutics' Entry into Tumors to Alleviate Tumoral Hypoxia

Anti-hypoxia cancer nanomedicine (AHCN) holds exciting potential in improving oxygen-dependent therapeutic efficiencies of malignant tumors. However, most studies regarding AHCN focus on optimizing structure and function of nanomaterials with presupposed successful entry into tumor cells. From such a traditional perspective, the main barrier that AHCN needs to overcome is mainly the tumor cell membrane. However, such an oversimplified perspective would neglect that real tumors have many biological, physiological, physical, and chemical defenses preventing the current state-of-the-art AHCNs from even reaching the targeted tumor cells. Fortunately, in recent years, some studies are beginning to intentionally focus on overcoming physiological barriers to alleviate hypoxia. In this Review, the limitations behind the traditional AHCN delivery mindset are addressed and the key barriers that need to be surmounted before delivery to cancer cells and some good ways to improve cell membrane attachment, internalization, and intracellular retention are summarized. It is aimed to contribute to Review literature on this emerging topic through refreshing perspectives based on this work and what is also learnt from others. This Review would therefore assist AHCNs researchers to have a quick overview of the essential information and glean thought-provoking ideas to advance this sub-field in cancer nanomedicine.

Cascade Reactions Catalyzed by Planar Metal-Organic Framework Hybrid Architecture for Combined Cancer Therapy

Chemical transformation in cellular environment is critical for regulating biological processes and metabolic pathways. Harnessing biocatalytic cascades to produce chemicals of interest has become a research focus to benefit industrial and pharmaceutic areas. Nanoreactors, which can act as artificial cell-like devices to organize cascade reactions, have been recently proposed for potential therapeutic applications for life-threatening illnesses. Among various types of nanomaterials, there is a growing interest in 2D metal-organic frameworks (MOFs). By virtue of the ultralarge specific surface area, high porosity, and structural diversity, 2D MOF nanosheets hold great promise for a broad spectrum of biomedical use. Herein, a unique planar MOF-based hybrid architecture (GMOF-LA) is introduced by incorporating ultrasmall gold nanoparticles (Au NPs) as nanozyme and l-Arginine (l-Arg) as nitric oxide (NO) donor. The prepared Au NPs enable oxidation of glucose into hydrogen peroxide, which drives biocatalytic cascades to covert l-Arg into NO. Interestingly, the well-designed nanosheets not only possess excellent catalytical activity for NO generation, resulting in gas therapeutic effect, but also serve as a desired photosensitizer for photodynamic therapy. This study establishes a good example of exploring bioinspired nanoreactors for cooperative anticancer effect, which may pave the path for future "bench-to-bedside" design of nanomedicine.

Computed tomography and photoacoustic imaging guided photodynamic therapy against breast cancer based on mesoporous platinum with insitu oxygen generation ability

Photodynamic therapy (PDT) has been widely used in cancer treatment. However, hypoxia in most solid tumors seriously restricts the efficacy of PDT. To improve the hypoxic microenvironment, we designed a novel mesoporous platinum (mPt) nanoplatform to catalyze hydrogen peroxide (H₂O₂) within the tumor cells in situ without an extra enzyme. During the fabrication, the carboxy terminus of the photosensitizer chlorin e6 (Ce6) was connected to the amino terminus of the bifunctional mercaptoaminopolyglycol (SH-PEG-NH₂) by a condensation reaction, and then PEG-Ce6 was modified onto the mPt moiety via the mercapto terminal of SH-PEG-NH₂. Material, cellular and animal experiments demonstrated that Pt@PEG-Ce6 catalyzed H₂O₂ to produce oxygen (O₂) and that Ce6 transformed O₂ to generate reactive oxygen species (ROS) upon laser irradiation. The Pt@PEG-Ce6 nanoplatform with uniform diameter presented good biocompatibility and efficient tumor accumulation. Due to the high atomic number and good near-infrared absorption for Pt, this Pt@PEG-Ce6 nanoplatform showed computed tomography (CT) and photoacoustic (PA) dual-mode imaging ability, thus providing an important tool for monitoring the tumor hypoxic microenvironment. Moreover, the Pt@PEG-Ce6 nanoplatform reduced the expression of hypoxia-inducible factor-1α (HIF-1α) and programmed death-1 (PD-1) in tumors, discussing the relationship between hypoxia, PD-1, and PDT for the first time.

A Nanomedicine Fabricated from Gold Nanoparticles-Decorated Metal-Organic Framework for Cascade Chemo/Chemodynamic Cancer Therapy

The incorporation of new modalities into chemotherapy greatly enhances the anticancer efficacy combining the merits of each treatment, showing promising potentials in clinical translations. Herein, a hybrid nanomedicine (Au/FeMOF@CPT NPs) is fabricated using metal-organic framework (MOF) nanoparticles and gold nanoparticles (Au NPs) as building blocks for cancer chemo/chemodynamic therapy. MOF NPs are used as vehicles to encapsulate camptothecin (CPT), and the hybridization by Au NPs greatly improves the stability of the nanomedicine in a physiological environment. Triggered by the high concentration of phosphate inside the cancer cells, Au/FeMOF@CPT NPs effectively collapse after internalization, resulting in the complete drug release and activation of the cascade catalytic reactions. The intracellular glucose can be oxidized by Au NPs to produce hydrogen dioxide, which is further utilized as chemical fuel for the Fenton reaction, thus realizing the synergistic anticancer efficacy. Benefitting from the enhanced permeability and retention effect and sophisticated fabrications, the blood circulation time and tumor accumulation of Au/FeMOF@CPT NPs are significantly increased. In vivo results demonstrate that the combination of chemotherapy and chemodynamic therapy effectively suppresses the tumor growth, meantime the systemic toxicity of this nanomedicine is greatly avoided.

Finely tuned Prussian blue-based nanoparticles and their application in disease treatment

The Prussian blue (PB) based nanostructure is a mixed-valence coordination network with excellent biosafety, remarkable photothermal effect and multiple enzyme-mimicking behaviours. Compared with other nanomaterials, PB-based nanoparticles (NPs) exhibit several unparalleled advantages in biomedical applications. This review begins with the chemical composition and physicochemical properties of PB-based NPs. The tuning strategies of PB-based NPs and their biomedical properties are systemically demonstrated. Afterwards, the biomedical applications of PB-based NPs are comprehensively recounted, mainly focusing on treatment of tumors, bacterial infection and inflammatory diseases. Finally, the challenges and future prospects of PB-based NPs and their application in disease treatment are discussed.

Tyrosinase-activated prodrug nanomedicine as oxidative stress amplifier for melanoma-specific treatment

Malignant melanoma is one of the most aggressive skin cancers, posing severe threat to human health. Tyrosinase, overexpressed in melanoma cells, is a specific in-situ weapon to augment the therapeutic efficacy of melanoma-specific treatment by in-situ accelerating the activation of anti-melanoma prodrugs. Herein, we developed a tyrosinase-triggered oxidative stress amplifier, denoted as APAP@PEG/HMnO₂, to achieve synergistic chemotherapy and amplified oxidative stress for melanoma-specific treatment. The APAP@PEG/HMnO₂ nanosystem was constructed by encapsulating non-toxic prodrug acetaminophen (APAP) into hollow PEG/HMnO₂ nanostructures. After tumor accumulation of APAP@PEG/HMnO₂ amplifier, substantial amounts of oxygen (O₂) was generated through reaction between HMnO₂ and excessive H₂O₂ present in tumor environment. Meanwhile, APAP was released at acidic tumor environment and subsequently activated by overexpressed tyrosinase in the presence of O₂ to produce cytotoxic benzoquinone metabolites (AOBQ). On the basis of the combinational effect of AOBQ-triggered reactive oxygen species (ROS) generation and synergistic glutathione (GSH) depletion as promoted by HMnO₂ and AOBQ, the APAP@PEG/HMnO₂ administration augmented the therapeutic efficacy of chemotherapy by amplifying the intratumoral oxidative stress, thus inducing remarkable cell apoptosis in vitro and tumor suppression in vivo. Therefore, the constructed prodrug nanomedicine represents a prospective tumor-specific therapeutic nanoagent for melanoma treatment.

Cu2 MoS4 /Au Heterostructures with Enhanced Catalase-Like Activity and Photoconversion Efficiency for Primary/Metastatic Tumors Eradication by Phototherapy-Induced Immunotherapy

Photoimmunotherapy can not only effectively ablate the primary tumor but also trigger strong antitumor immune responses against metastatic tumors by inducing immunogenic cell death. Herein, Cu₂ MoS₄ (CMS)/Au heterostructures are constructed by depositing plasmonic Au nanoparticles onto CMS nanosheets, which exhibit enhanced absorption in near-infrared (NIR) region due to the newly formed mid-gap state across the Fermi level based on the hybridization between Au 5d orbitals and S 3p orbitals, thus resulting in more excellent photothermal therapy and photodynamic therapy (PDT) effect than single CMS upon NIR laser irradiation. The CMS and CMS/Au can also serve as catalase to effectively relieve tumor hypoxia, which can enhance the therapeutic effect of O₂ -dependent PDT. Notably, the NIR laser-irradiated CMS/Au can elicit strong immune responses via promoting dendritic cells maturation, cytokine secretion, and activating antitumor effector T-cell responses for both primary and metastatic tumors eradication. Moreover, CMS/Au exhibits outstanding photoacoustic and computed tomography imaging performance owing to its excellent photothermal conversion and X-ray attenuation ability. Overall, the work provides an imaging-guided and phototherapy-induced immunotherapy based on constructing CMS/Au heterostructures for effectively tumor ablation and cancer metastasis inhibition.