Conferring Ti-Based MOFs with Defects for Enhanced Sonodynamic Cancer Therapy

Resveratrol-Coated Gold Nanoflowers for CT Imaging and Apoptosis/Photothermal Synergistic Therapy of Malignant Melanoma

In the past decade, photothermal therapy (PTT) of tumors based on gold nanomaterials has been widely studied because of their strong extinction ability and high photothermal conversion ability in the near-infrared (NIR) region. However, related research still faces two problems: First, the biosafety of the surface ligands on gold nanomaterials is not ideal and even has strong toxicity, so the surface modification or shell coating is very necessary; second, gold nanomaterials only have a single PTT function, which requires high temperature to achieve better treatment effect. Therefore, it is necessary to enrich the antitumor function of gold nanomaterials and realize synergistic therapy. Natural polyphenols can combine with each other or other substances through various supramolecular forces, forming shells on the surface of nanomaterials and reducing biotoxicity. In addition, natural polyphenols represented by resveratrol have antitumor activity and can induce apoptosis of tumor cells. Therefore, the surface coating method of gold nanomaterials with natural polyphenols with antitumor activity can effectively solve the above problems. In this work, we prepared resveratrol-coated gold nanoflowers (Au@Res NFs) and applied them to the treatment of malignant melanoma. Resveratrol in Au@Res NFs can induce the apoptosis of tumor cells, and Au@Res NFs can play a role in PTT under an NIR laser. In cell experiments, the synergistic effect of apoptosis/PTT on the A375 cells was extremely strong. In animal experiments, Au@Res NFs enriched in tumor sites identified the location and boundary of tumors by computed tomography (CT). The apoptosis induced by resveratrol had a certain inhibitory effect on tumor growth. Further applying the NIR laser, under the synergistic effect of apoptosis and PTT, the tumors were completely eliminated without recurrence during the experimental period.

Oxygen-defective zinc oxide nanoparticles as highly efficient and safe sonosensitizers for cancer therapy

Herein, an oxygen defect-modulated zinc oxide sonosensitizer is designed, which enhances the absorbance of ultrasound energy and suppresses the recombination of ultrasound-initiated electrons and holes to promote reactive oxygen species yield. It achieves a high tumor inhibition efficiency of 79.9%, which exhibits a potential application for sonodynamic cancer therapy.

Sonocatalytic Optimization of Titanium-Based Therapeutic Nanomedicine

Recent considerable technological advances in ultrasound-based treatment modality provides a magnificent prospect for scientific communities to conquer the related diseases, which is featured with remarkable tissue penetration, non-invasive and non-thermal characteristics. As one of the critical elements that influences treatment outcomes, titanium (Ti)-based sonosensitizers with distinct physicochemical properties and exceptional sonodynamic efficiency have been applied extensively in the field of nanomedical applications. To date, a myriad of methodologies has been designed to manipulate the sonodynamic performance of titanium-involved nanomedicine and further enhance the productivity of reactive oxygen species for disease treatments. In this comprehensive review, the sonocatalytic optimization of diversified Ti-based nanoplatforms, including defect engineering, plasmon resonance modulation, heterojunction, modulating tumor microenvironment, as well as the development of synergistic therapeutic modalities is mainly focused. The state-of-the-art Ti-based nanoplatforms ranging from preparation process to the extensive medical applications are summarized and highlighted, with the goal of elaborating on future research prospects and providing a perspective on the bench-to-beside translation of these sonocatalytic optimization tactics. Furthermore, to spur further technological advancements in nanomedicine, the difficulties currently faced and the direction of sonocatalytic optimization of Ti-based therapeutic nanomedicine are proposed and outlooked.

Recent Developments of Inorganic Nanosensitizers for Sonodynamic Therapy

As a noninvasive treatment, sonodynamic therapy (SDT) has been widely used in the treatment of tumors because of its ability to penetrate deep tissue with few side effects. As the key factor of SDT, it is meaningful to design and synthesize efficient sonosensitizers. Compared with organic sonosensitizers, inorganic sonosensitizers can be easily excited by ultrasound. In addition, inorganic sonosensitizers with stable properties, good dispersion, and long blood circulation time, have great development potential in SDT. This review summarizes possible mechanisms of SDT (sonoexcitation and ultrasonic cavitation) in detail. Based on these mechanisms, the design and synthesis of inorganic nanosonosensitizers can be divided into three categories: traditional inorganic semiconductor sonosensitizers, enhanced inorganic semiconductor sonosensitizers, and cavitation-enhanced sonosensitizers. Subsequently, the current efficient construction methods of sonosensitizers are summarized including accelerated semiconductor charge separation and enhanced production of reactive oxygen species through ultrasonic cavitation. Furthermore, the advantages and disadvantages of different inorganic sonosensitizers and detailed strategies are systematically discussed on how to enhance SDT. Hopefully, this review could provide new insights into the design and synthesis of efficient inorganic nano-sonosensitizers for SDT.

Defect Engineering in Biomedical Sciences

With the promotion of nanochemistry research, large numbers of nanomaterials have been applied in vivo to produce desirable cytotoxic substances in response to endogenous or exogenous stimuli for achieving disease-specific therapy. However, the performance of nanomaterials is a critical issue that is difficult to improve and optimize under biological conditions. Defect-engineered nanoparticles have become the most researched hot materials in biomedical applications recently due to their excellent physicochemical properties, such as optical properties and redox reaction capabilities. Importantly, the properties of nanomaterials can be easily adjusted by regulating the type and concentration of defects in the nanoparticles without requiring other complex designs. Therefore, this tutorial review focuses on biomedical defect engineering and briefly discusses defect classification, introduction strategies, and characterization techniques. Several representative defective nanomaterials are especially discussed in order to reveal the relationship between defects and properties. A series of disease treatment strategies based on defective engineered nanomaterials are summarized. By summarizing the design and application of defective engineered nanomaterials, a simple but effective methodology is provided for researchers to design and improve the therapeutic effects of nanomaterial-based therapeutic platforms from a materials science perspective.

Copper-Single-Atom Coordinated Nanotherapeutics for Enhanced Sonothermal-Parallel Catalytic Synergistic Cancer Therapy

Phototherapy and sonotherapy are recognized by scientific medicine as effective strategies for treating certain cancers. However, these strategies have limitations such as an inability to penetrate deeper tissues and overcome the antioxidant tumor microenvironment. In this study, a novel "BH" interfacial-confined coordination strategy to synthesize hyaluronic acid-functionalized single copper atoms dispersed over boron imidazolate framework-derived nanocubes (HA-NC_Cu) to achieve sonothermal-catalytic synergistic therapy is reported. Notably, HA-NC_Cu demonstrates exceptional sonothermal conversion performance under low-intensity ultrasound irradiation, attained through intermolecular lattice vibrations. In addition, it shows promise as an efficient biocatalyst, able to generate high-toxicity hydroxyl radicals in response to tumor-endogenous hydrogen peroxide and glutathione. Density functional theory calculations reveal that the superior parallel catalytic performance of HA-NC_Cu originates from the CuN4 C/B active sites. Both in vitro and in vivo evaluations consistently demonstrate that the sonothermal-catalytic synergistic strategy significantly improves tumor inhibition rate (86.9%) and long-term survival rate (100%). In combination with low-intensity ultrasound irradiation, HA-NC_Cu triggers a dual death pathway of apoptosis and ferroptosis in MDA-MB-231 breast cancer cells, comprehensively limiting primary triple-negative breast cancer. This study highlights the applications of single-atom-coordinated nanotherapeutics in sonothermal-catalytic synergistic therapy, which may create new opportunities in biomedical research.

2D Piezoelectric BiVO4 Artificial Nanozyme with Adjustable Vanadium Vacancy for Ultrasound Enhanced Piezoelectric/Sonodynamic Therapy

Increasing the yield of reactive oxygen species (ROS) to enhance oxidative stress in cells is an eternal goal in cancer therapy. In this study, BiVO4 artificial nanozyme is developed with adjustable vanadium vacancy for ultrasound (US) enhanced piezoelectric/sonodynamic therapy. Under US excitation, the vanadium vacancy-rich BiVO4 nanosheets (abbreviated Vv -r BiVO4 NSs) facilitate the generation of a large number of electrons to improve the ROS yield. Meanwhile, the mechanical strain imposed by US irradiation makes the Vv -r BiVO4 NSs display a typical piezoelectric response, which tilts the conduction band to be more negative and the valance band more positive than the redox potentials of O2 /O2 •- and H2 O/·OH, boosting the efficiency of ROS generation. Both density functional theory calculations and experiments confirm that the introduction of cationic vacancy can improve the sonodynamic effect. As expected, Vv -r BiVO4 NSs have better peroxidase enzyme catalytic and glutathione depletion activities, resulting in increased intracellular oxidative stress. This triple amplification strategy of oxidative stress induced by US substantially inhibits the growth of cancer cells. The work may open an avenue to achieve a synergetic therapy by introducing cationic vacancy, broadening the biomedical use of piezoelectric materials.

Lattice Strain Engineering of Ti3C2 Narrows Band Gap for Realizing Extraordinary Sonocatalytic Bacterial Killing

The rapid development of sonodynamic therapy (SDT) provides a promising strategy for treating deep-seated multidrug-resistant (MDR) bacterial infection. However, the extreme scarcity of biologically functional and highly efficient sonosensitizers severely limits the further clinical practice of SDT. Herein, the lattice-strain-rich Ti3C2 (LS-Ti3C2) with greatly improved sonosensitizing effect is one-step synthesized using Ti3C2 and meso-tetra(4-carboxyphenyl)porphine (TCPP) by the solvothermal method for realizing extraordinary SDT. The intervention of TCPP causes all the Ti-O chemical bonds and most of the Ti-F chemical bonds on the surface layer of Ti3C2 to break down. The amino groups of TCPP are then recombined with these exposed Ti atoms to perturb the order of the Ti atoms, resulting in displacement of the Ti atoms and final lattice structural distortion of Ti3C2. The inherent lattice strain narrows the band gap of Ti3C2, which mainly facilitates the electron-hole pair separation and electron transfer under ultrasound irradiation, thereby resulting in US-mediated reactive oxygen species (ROS) production and the subsequent robust bactericidal capability (99.77 ± 0.16%) against methicillin-resistant Staphylococcus aureus (MRSA). Overall, this research offers a perspective into the development of Ti-familial sonosensitizers toward SDT practice.

A Novel Platform of MOF for Sonodynamic Therapy Advanced Therapies

Metal-organic frameworks (MOFs) combined with sonodynamic therapy (SDT) have been introduced as a new and efficient treatment method. The critical advantage of SDT is its ability to penetrate deep tissues and concentrate energy on the tumor site to achieve a non-invasive or minimally invasive effect. Using a sonosensitizer to generate reactive oxygen species (ROS) under ultrasound is the primary SDT-related method of killing tumor cells. In the presence of a sonosensitizer, SDT exhibits a more lethal effect on tumors. The fast development of micro/nanotechnology has effectively improved the efficiency of SDT, and MOFs have been broadly evaluated in SDT due to their easy synthesis, easy surface functionalization, high porosity, and high biocompatibility. This article reviews the main mechanism of action of sonodynamic therapy in cancer treatment, and also reviews the applications of MOFs in recent years. The application of MOFs in sonodynamic therapy can effectively improve the targeting ability of SDT and the conversion ability of reactive oxygen species, thus improving their killing ability on cancer cells. This provides new ideas for the application of micro/nano particles in SDT and cancer therapy.

Ultrasound-Triggered Cascade Amplification of Nanotherapy

Ultrasound (US)-triggered cascade amplification of nanotherapies has attracted considerable attention as an effective strategy for cancer treatment. With the remarkable advances in materials chemistry and nanotechnology, a large number of well-designed nanosystems have emerged that incorporate presupposed cascade amplification processes and can be activated to trigger therapies such as chemotherapy, immunotherapy, and ferroptosis, under exogenous US stimulation or specific substances generated by US actuation, to maximize antitumor efficacy and minimize detrimental effects. Therefore, summarizing the corresponding nanotherapies and applications based on US-triggered cascade amplification is essential. This review comprehensively summarizes and highlights the recent advances in the design of intelligent modalities, consisting of unique components, distinctive properties, and specific cascade processes. These ingenious strategies confer unparalleled potential to nanotherapies based on ultrasound-triggered cascade amplification and provide superior controllability, thus overcoming the unmet requirements of precision medicine and personalized treatment. Finally, the challenges and prospects of this emerging strategy are discussed and it is expected to encourage more innovative ideas and promote their further development.

Covalent Organic Framework Nanocages with Enhanced Carrier Utilization and Cavitation Effect for Cancer Sonodynamic Therapy

Ultrasound (US)-triggered sonodynamic therapy (SDT) is an emerging method for treating cancer due to its non-invasive nature and high-depth tissue penetration ability. However, current sonosensitizers commonly have unsatisfactory quantum yields of free radicals. In this work, we have developed unique organic semiconductor π-conjugated covalent organic framework nanocages (COFNs) as highly efficient sonosensitizers to boost free radical (¹O₂ and ^•OH) production and cancer therapy. With the hollow and porous structure and band transport behavior, COFNs displayed remarkably improved SDT performance through enhanced electron utilization and cavitation effect, with a 1.8-fold increase in US pressure and a 64.8% increase in ¹O₂ production relative to the core-shell-structured COF under US irradiation. The in vitro and in vivo experimental results verified the elevated SDT performance, showing a high tumor suppression of 91.4% against refractory breast cancer in mice. This work provides a promising strategy to develop high-performance sonosensitizers for cancer therapy.

Light-Driven and Metal-Organic Framework Synergetic Loaded DNA Tetrahedral Amplifier for Exonuclease III-Powered All-in-One Biosensing and Chemotherapy in Live Biosystems

As a result of inaccurate biosensing and difficult synergetic loading, it is challenging to further impel DNA amplifiers to perform therapeutic application. Herein, we introduce some innovative solutions. First, a smart light-driven biosensing concept based on embedding nucleic acid modules with a simple photocleavage-linker is proposed. In this system, the target identification component is exposed on irradiation with ultraviolet light, thus avoiding an always-on biosensing response during biological delivery. Further, in addition to providing controlled spatiotemporal behavior and precise biosensing information, a metal-organic framework is used for the synergetic loading of doxorubicin in the internal pores, whereafter a rigid DNA tetrahedron-sustained exonuclease III-powered biosensing system is attached to prevent drug leakage and enhance resistance to enzymatic degradation. By selecting a next-generation breast cancer correlative noncoding microRNA biomarker (miRNA-21) as a model low-abundance analyte, a highly sensitive in vitro detection ability even allowing to distinguish single-base mismatching is demonstrated. Moreover, the all-in-one DNA amplifier shows excellent bioimaging competence and good chemotherapy efficacy in live biosystems. These findings will drive research into the use of DNA amplifiers in diagnosis and therapy integrated fields.

Engineering Dynamic Defect of CeIII /CeIV -Based Metal-Organic Framework through Ultrasound-Triggered Au Electron Trapper for Sonodynamic Therapy of Osteomyelitis

Defect engineering is an important way to tune the catalytic properties of metal-organic framework (MOF), yet precise control of defects is difficult to achieve. Herein, a cerium-based MOF (CeTCPP) is decorated with Au nanoparticles. Under ultrasound irradiation, Au nanoparticles can precisely turn 1/3 of the pristine Ce³⁺ nodes into Ce⁴⁺ . With the stable existence of Ce⁴⁺ , the coordination of Ce nodes changed, causing the structural irregularity in CeTCPP-Au, so that the electron-hole recombination is obviously hindered, facilitating the generation of reactive oxygen species. Therefore, under 20 min of ultrasound irradiation, the CeTCPP-Au showed superior antibacterial efficacy of over 99% against Staphylococcus aureus and Escherichia coli with good biocompatibility, which is further used for effective therapy of osteomyelitis. Overall, this work provides a dynamic defect formation strategy of MOF through the electron trapping of Au nanoparticles, which also sheds light on sonodynamic therapy in curing deep-seated lesions.

Metal-Organic Frameworks Facilitate Nucleic Acids for Multimode Synergistic Therapy of Breast Cancer

Compared with traditional medical methods, gene therapy and photodynamic therapy are the new fields of cancer treatment, and they more accurately and effectively obtain preferable therapeutic effects. In this study, a chemotherapy drug-free nanotherapeutic system based on ZIF-90 encapsulated with Ce6-G3139 and Ce6-DNAzyme for gene and photodynamic therapies was constructed. Once entering the cancer cell, the therapy system will decompose and release Zn²⁺, Ce6-G3139, and Ce6-DNAzyme in the acidic environment. On the one hand, G3139 binds to the antiapoptotic gene BCL-2 in tumor cells and downregulates related proteins to inhibit tumor proliferation. On the other hand, Zn²⁺ produced by the decomposition of ZIF-90 can be used as a cofactor to activate the cleavage activity of DNAzyme to initiate gene therapy. Proliferation and metastasis of tumors were further inhibited by DNAzyme, targeting and cutting the gene of human early growth factor-1 (EGR-1). In addition, the photosensitizer Ce6 carried by the nucleic acid will produce cytotoxic ROS to kill cancer cells after irradiation. The results of this study demonstrated that the designed nanoplatform, which synergistically combines gene and photodynamic therapies, has shown great potential for cancer treatment.

H2O2/O2 self-supply and Ca2+ overloading MOF-based nanoplatform for cascade-amplified chemodynamic and photodynamic therapy

Introduction: Reactive oxygen species (ROS)-mediated therapies have typically been considered as noninvasive tumor treatments owing to their high selectivity and efficiency. However, the harsh tumor microenvironment severely impairs their efficiency. Methods: Herein, the biodegradable Cu-doped zeolitic imidazolate framework-8 (ZIF-8) was synthesized for loading photosensitizer Chlorin e6 (Ce6) and CaO₂ nanoparticles, followed by surface decoration by hyaluronic acid (HA), obtaining HA/CaO₂-Ce6@Cu-ZIF nano platform. Results and Discussion: Once HA/CaO₂-Ce6@Cu-ZIF targets tumor sites, the degradation of Ce6 and CaO₂ release from the HA/CaO₂-Ce6@Cu-ZIF in response to the acid environment, while the Cu²⁺ active sites on Cu-ZIF are exposed. The released CaO₂ decompose to generate hydrogen peroxide (H₂O₂) and oxygen (O₂), which alleviate the insufficiency of intracellular H₂O₂ and hypoxia in tumor microenvironment (TME), effectively enhancing the production of hydroxyl radical (•OH) and singlet oxygen (¹O₂) in Cu²⁺-mediated chemodynamic therapy (CDT) and Ce6-induced photodynamic therapy (PDT), respectively. Importantly, Ca²⁺ originating from CaO₂ could further enhance oxidative stress and result in mitochondrial dysfunction induced by Ca²⁺ overloading. Conclusion: Thus, the H₂O₂/O₂ self-supplying and Ca²⁺ overloading ZIF-based nanoplatform for cascade-amplified CDT/PDT synergistic strategy is promising for highly efficient anticancer therapy.

Antitumor Effects of a Distinct Sonodynamic Nanosystem through Enhanced Induction of Immunogenic Cell Death and Ferroptosis with Modulation of Tumor Microenvironment

Sonodynamic therapy (SDT) holds great promise to be applied for cancer therapy in clinical settings. However, its poor therapeutic efficacy has limited its applications owing to the apoptosis-resistant mechanism of cancer cells. Moreover, the hypoxic and immunosuppressive tumor microenvironment (TME) also weakens the efficacy of immunotherapy in solid tumors. Therefore, reversing TME remains a formidable challenge. To circumvent these critical issues, we developed an ultrasound-augmented strategy to regulate the TME by utilizing an HMME-based liposomal nanosystem (HB liposomes), which can synergistically promote the induction of ferroptosis/apoptosis/immunogenic cell death (ICD) and initiate the reprograming of TME. The RNA sequencing analysis demonstrated that apoptosis, hypoxia factors, and redox-related pathways were modulated during the treatment with HB liposomes under ultrasound irradiation. The in vivo photoacoustic imaging experiment showed that HB liposomes enhanced oxygen production in the TME, alleviated TME hypoxia, and helped to overcome the hypoxia of the solid tumors, consequently improving the SDT efficiency. More importantly, HB liposomes extensively induced ICD, resulting in enhanced T-cell recruitment and infiltration, which normalizes the immunosuppressive TME and facilitates antitumor immune responses. Meanwhile, the HB liposomal SDT system combined with PD1 immune checkpoint inhibitor achieves superior synergistic cancer inhibition. Both in vitro and in vivo results indicate that the HB liposomes act as a sonodynamic immune adjuvant that is able to induce ferroptosis/apoptosis/ICD via generated lipid-reactive oxide species during the SDT and reprogram TME due to ICD induction. This sonodynamic nanosystem integrating oxygen supply, reactive oxygen species generation, and induction of ferroptosis/apoptosis/ICD is an excellent strategy for effective TME modulation and efficient tumor therapy.

Metal-Organic Framework-Derived Homologous Sulfide Heterojunction for Robust Enzyme-Like Self-Driven Bacteria-Killing through Enhanced Electron Transfer

Infectious diseases caused by various bacteria pose a serious threat to human health, and the emergence of drug-resistant bacteria has forced humans to develop new and effective antimicrobial agents and strategies. Herein, a metal-organic framework-derived Bi₂ S₃ /FeS₂ heterojunction (BFS) is synthesized, and the materials-microorganism interface is further constructed. Through interfacial electron transfer, electrons are transferred from the bacteria to the BFS surface, disrupting the balance of the bacterial electron transport chain and inhibiting the metabolic activity of the bacteria. Moreover, BFS has enzyme-like (oxidase and peroxidase) properties and can produce a large amount of reactive oxygen species to kill additional bacteria. In vitro antibacterial results show that the antibacterial efficiency of BFS against both Staphylococcus aureus and Escherichia coli reaches more than 99.9% after 4 h of co-culture under dark conditions. Meanwhile, in vivo experiments show that BFS can effectively kill bacteria and promote wound healing. This work shows that BFS could be a novel, effective nanomaterial for the treatment of bacterial infections by constructing the materials-microorganism interface.

Tumor-targeted AIE polymeric micelles mediated immunogenic sonodynamic therapy inhibits cancer growth and metastasis

Aggregation-induced emission luminogens (AIEgens) exhibit potent sonosensitivity in nanocarriers compared with conventional organic sonosensitizers owing to the strong fluorescence emission in the aggregated state. However, the premature drug leakage and ineffective tumor targeting of current AIE nanosonosensitizers critically restrict their clinical applications. Here, an AIEgen-based sonosensitizer (AIE/Biotin-M) with excellent sonosensitivity was developed by assembling salicylaldazine-based amphiphilic polymers (AIE-1) and 4T1 tumor-targeting amphiphilic polymers (DSPE-PEG-Biotin) for the effective delivery of salicylaldazine to 4T1 tumor tissues, aiming to mediate immunogenic SDT. In vitro, AIE/Biotin-M were highly stable and generated plentiful singlet oxygen (¹O₂) under ultrasound (US) irradiation. After AIE/Biotin-M targeted accumulation in the tumor, upon US irradiation, the generation of ¹O₂ not only led to cancer cell death, but also elicited a systemically immune response by causing the immunogenic cell death (ICD) of cancer cells. In addition to mediating SDT, AIE/Biotin-M could chelate and reduce Fe³⁺, Cu²⁺ and Zn²⁺ by salicylaldazine for inhibiting neovascularization in tumor tissues. Ultimately, AIE/Biotin-M systemically inhibited tumor growth and metastasis upon US irradiation. This study presents a facile approach to the development of AIE nanosonosensitizers for cancer SDT.

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.

Hyperbaric Oxygen Activates Enzyme-Driven Cascade Reactions for Cooperative Cancer Therapy and Cancer Stem Cells Elimination

Tumor starvation induced by intratumor glucose depletion emerges as a promising strategy for anticancer therapy. However, its antitumor potencies are severely compromised by intrinsic tumor hypoxia, low delivery efficiencies, and undesired off-target toxicity. Herein, a multifunctional cascade bioreactor (HCG), based on the self-assembly of pH-responsive hydroxyethyl starch prodrugs, copper ions, and glucose oxidase (GOD), is engineered, empowered by hyperbaric oxygen (HBO) for efficient cooperative therapy against aggressive breast cancers. Once internalized by tumor cells, HCG undergoes disassembly and releases cargoes in response to acidic tumor microenvironment. Subsequently, HBO activates GOD-catalyzed oxidation of glucose to H₂ O₂ and gluconic acid by ameliorating tumor hypoxia, fueling copper-catalyzed •OH generation and pH-responsive drug release. Meanwhile, HBO degrades dense tumor extracellular matrix, promoting tumor accumulation and penetration of HCG. Moreover, along with the consumption of glucose and the redox reaction of copper ions, the antioxidant capacity of tumor cells is markedly reduced, collectively boosting oxidative stress. As a result, the combination of HCG and HBO can not only remarkably suppress the growth of orthotopic breast tumors but also restrain pulmonary metastases by inhibiting cancer stem cells. Considering the clinical accessibility of HBO, this combined strategy holds significant translational potentials for GOD-based therapies.

Metal-Organic Framework (MOF)-A Universal Material for Biomedicine

Metal-organic frameworks (MOFs) are a very promising platform for applications in various industries. In recent years, a variety of methods have been developed for the preparation and modification of MOFs, providing a wide range of materials for different applications in life science. Despite the wide range of different MOFs in terms of properties/sizes/chemical nature, they have not found wide application in biomedical practices at present. In this review, we look at the main methods for the preparation of MOFs that can ensure biomedical applications. In addition, we also review the available options for tuning the key parameters, such as size, morphology, and porosity, which are crucial for the use of MOFs in biomedical systems. This review also analyses possible applications for MOFs of different natures. Their high porosity allows the use of MOFs as universal carriers for different therapeutic molecules in the human body. The wide range of chemical species involved in the synthesis of MOFs makes it possible to enhance targeting and prolongation, as well as to create delivery systems that are sensitive to various factors. In addition, we also highlight how injectable, oral, and even ocular delivery systems based on MOFs can be used. The possibility of using MOFs as therapeutic agents and sensitizers in photodynamic, photothermal, and sonodynamic therapy was also reviewed. MOFs have demonstrated high selectivity in various diagnostic systems, making them promising for future applications. The present review aims to systematize the main ways of modifying MOFs, as well as the biomedical applications of various systems based on MOFs.

Boosting the Sonodynamic Cancer Therapy Performance of 2D Layered Double Hydroxide Nanosheet-Based Sonosensitizers Via Crystalline-to-Amorphous Phase Transformation

Sonodynamic therapy (SDT) has been a promising therapeutic modality for cancer because of its superior advantages compared with other therapeutic strategies. However, the current sonosensitizers used for SDT normally exhibit low activity for ultrasound (US)-induced reactive oxygen species (ROS) generation. Herein, the crystalline-to-amorphous phase transformation is reported as a simple but powerful strategy to engineer ultrathin 2D CoW-LDH and NiW-LDH nanosheets as highly efficient sonosensitizers for SDT. The phase transformation of CoW-LDH and NiW-LDH nanosheets from polycrystalline to amorphous ones is achieved through a simple acid etching treatment. Importantly, compared with the polycrystalline one, the amorphous CoW-LDH (a-CoW-LDH) nanosheets possess higher ROS generation activity under US irradiation, which is ≈17 times of the commercial TiO₂ sonosensitizer. The results suggest that the enhanced performance of ultrathin a-CoW-LDH nanosheets for US-induced ROS generation may be attributed to the phase transformation-induced defect generation and electronic structure changes. After polyethylene glycol modification, the a-CoW-LDH nanosheets can serve as a high-efficiency sonosensitizer for SDT to achieve cell death in vitro and tumor eradication in vivo under US irradiation.

Perovskite-Type Manganese Vanadate Sonosensitizers with Biodegradability for Enhanced Sonodynamic Therapy of Cancer

Sonodynamic therapy (SDT) has attracted intensive attention, but is still hindered by low sonosensitization and non-biodegradability of the traditional sonosensitizers. Herein, perovskite-type manganese vanadate (MnVO₃ ) sonosensitizers integrating high reactive oxide species (ROS) production efficiency and appropriate bio-degradability are developed for enhanced SDT. Taking advantage of the intrinsic properties of perovskites such as narrow bandgap and substantial oxygen vacancies, MnVO₃ shows a facile ultrasound (US)-triggered electrons-holes separation and restrained recombination, thus enhancing the ROS quantum yield in SDT. Furthermore, MnVO₃ exhibits a considerable chemodynamic therapy (CDT) effect under the acidic condition probably owing to the presence of manganese and vanadium ions. Due to the presence of high-valent vanadium, MnVO₃ can also eliminate glutathione (GSH) within the tumor microenvironment, which synergistically amplifies the efficacy of SDT and CDT. Importantly, the perovskite structure bestows MnVO₃ with superior biodegradability, which alleviates the long-term presence of residues in metabolic organs after therapeutic actions. Based on these characteristics, US-assisted MnVO₃ achieves an excellent antitumor outcome along with low systemic toxicity. Overall, perovskite-type MnVO₃ may be promising sonosensitizers for highly efficient and safe treatment of cancer. The work attempts to explore the potential utility of perovskites in the design of degradable sonosensitizers.

Metal-Organic Frameworks (MOF)-Assisted Sonodynamic Therapy in Anticancer Applications

Sonodynamic therapy (SDT) has emerged as a promising therapeutic modality for anticancer treatments and is becoming a cutting-edge interdisciplinary research field. This review starts with the latest developments of SDT and provides a brief comprehensive discussion on ultrasonic cavitation, sonodynamic effect, and sonosensitizers in order to popularize the basic principles and probable mechanisms of SDT. Then the recent progress of MOF-based sonosensitizers is overviewed, and the preparation methods and properties (e.g., morphology, structure, and size) of products are presented in a fundamental perspective. More importantly, many deep observations and understanding toward MOF-assisted SDT strategies were described in anticancer applications, aiming to highlight the advantages and improvements of MOF-augmented SDT and synergistic therapies. Last but not least, the review also pointed out the probable challenges and technological potential of MOF-assisted SDT for the future advance. In all, the discussions and summaries of MOF-based sonosensitizers and SDT strategies will promote the fast development of anticancer nanodrugs and biotechnologies.

Mesocrystalline ZnS nanoparticles-augmented sonocatalytic full water splitting into H2/O2 for immunoactivating deep tumor

Therapeutic gas molecules have high tissue penetrability, but their sustainable supply and controlled release in deep tumor is a huge challenge. In this work, a concept of sonocatalytic full water splitting for hydrogen/oxygen immunotherapy of deep tumor is proposed, and a new kind of ZnS nanoparticles with a mesocrystalline structure (mZnS) is developed to achieve highly efficient sonocatalytic full water splitting for sustainable supply of H₂ and O₂ in tumor, achieving a high efficacy of deep tumor therapy. Mechanistically, locally generated hydrogen and oxygen molecules exhibit a tumoricidal effect as well as the co-immunoactivation of deep tumors through inducing the M2-to-M1 repolarization of intratumoral macrophages and the tumor hypoxia relief-mediated activation of CD8⁺ T cells, respectively. The proposed sonocatalytic immunoactivation strategy will open a new window to realize safe and efficient treatment of deep tumors.

BioMOF-Based Anti-Cancer Drug Delivery Systems

A variety of nanomaterials have been developed specifically for biomedical applications, such as drug delivery in cancer treatment. These materials involve both synthetic and natural nanoparticles and nanofibers of varying dimensions. The efficacy of a drug delivery system (DDS) depends on its biocompatibility, intrinsic high surface area, high interconnected porosity, and chemical functionality. Recent advances in metal-organic framework (MOF) nanostructures have led to the achievement of these desirable features. MOFs consist of metal ions and organic linkers that are assembled in different geometries and can be produced in 0, 1, 2, or 3 dimensions. The defining features of MOFs are their outstanding surface area, interconnected porosity, and variable chemical functionality, which enable an endless range of modalities for loading drugs into their hierarchical structures. MOFs, coupled with biocompatibility requisites, are now regarded as highly successful DDSs for the treatment of diverse diseases. This review aims to present the development and applications of DDSs based on chemically-functionalized MOF nanostructures in the context of cancer treatment. A concise overview of the structure, synthesis, and mode of action of MOF-DDS is provided.

Titanium-Based Nanoarchitectures for Sonodynamic Therapy-Involved Multimodal Treatments

Sonodynamic therapy (SDT) has considerably revolutionized the healthcare sector as a viable noninvasive therapeutic procedure. It employs a combination of low-intensity ultrasound and chemical entities, known as a sonosensitizer, to produce cytotoxic reactive oxygen species (ROS) for cancer and antimicrobial therapies. With nanotechnology, several unique nanoplatforms are introduced as a sonosensitizers, including, titanium-based nanomaterials, thanks to their high biocompatibility, catalytic efficiency, and customizable physicochemical features. Additionally, developing titanium-based sonosensitizers facilitates the integration of SDT with other treatment modalities (for example, chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy), hence increasing overall therapeutic results. This review summarizes the most recent developments in cancer therapy and tissue engineering using titanium nanoplatforms mediated SDT. The synthesis strategies and biosafety aspects of Titanium-based nanoplatforms for SDT are also discussed. Finally, various challenges and prospects for its further development and potential clinical translation are highlighted.

Nanosonosensitizers-engineered injectable thermogel for augmented chemo-sonodynamic therapy of melanoma and infected wound healing

Easy recurrence and bacteria infected-wound healing after surgery excision pose severe challenges to clinical melanoma therapy. Herein, an injectable CuO₂ nanodots-engineered thermosensitive chitosan hydrogel (CuO₂-BSO@Gel) for enhanced melanoma chemo-sonodynamic therapy and improved infected wound healing was rationally constructed by facilely integrating the CuO₂ nanodots and L-Buthionine-(S, R)-sulfoximine (BSO) with thermoresponsive hydrogel. Favored by the Fenton catalytic activity of Cu²⁺, the CuO₂ nanodots can achieve enhanced chemodynamic therapy (CDT) by self-supplying H₂O₂ under acidic tumor microenvironment. Simultaneously, the CuO₂ nanodots with a narrow bandgap (2.29 ​eV) were proven to be the efficient sonosensitizers, and the corresponding quantum yield of singlet oxygen (¹O₂) could be boosted by the O₂ generation during Fenton-like reactions. Additionally, combining with the glutathione (GSH) depletion of loaded BSO, intracellular oxidative stress induced by SDT and CDT was further amplified, leading to the specific ferroptosis. Importantly, this multifunctional hydrogel significantly promoted the proliferation of normal skin cells and accelerated the bacteria-infected wound healing by the effective chemo-sonodynamic antibacterial activity and the enhanced angiogenesis. Thus, the engineered thermogel features the distinct chemo-sonodynamic performance, desirable biocompatibility and bioactivity, providing a competitive strategy for eradicating melanoma and infected wound healing.

A New Sono-Chemo Sensitizer Overcoming Tumor Hypoxia for Augmented Sono/Chemo-Dynamic Therapy and Robust Immune-Activating Response

Novel sonosensitizers with intrinsic characteristics for tumor diagnosis, efficient therapy, and tumor microenvironment regulation are appealing in current sonodynamic therapy. Herein, a manganese (Mn)-layered double hydroxide-based defect-rich nanoplatform is presented as a new type of sono-chemo sensitizer, which allows ultrasound to efficiently trigger reactive oxygen species generation for enhanced sono/chemo-dynamic therapy. Moreover, such a nanoplatform is able to relieve tumor hypoxia and achieve augmented singlet oxygen production via catalyzing endogenous H2 O2 into O2 . On top of these actions, the released Mn2+ ions and immune-modulating agent significantly intensify immune activation and reverse the immunosuppressive tumor microenvironment to the immunocompetent one. Consequently, this nanoplatform exhibits excellent anti-tumor efficacy and effectively suppresses both primary and distant tumor growth, demonstrating a new strategy to functionalize nanoparticles as sono-chemo sensitizers for synergistic combination cancer therapy.

Inflammatory Cell-Inspired Cascade Nanozyme Induces Intracellular Radical Storm for Enhanced Anticancer Therapy

Manipulating intracellular levels of reactive oxygen and nitrogen species (RONS) is of great potential for cancer treatment. Inspired by the natural mechanism of a radical storm in inflammatory cells via activated and regulatable biocatalysis, the authors herein report a self-powered nanozyme that can enable RONS production in tumor cells via cascade reactions. The nanozymes are constructed via glucose oxidase (GOx)-templated inverse microemulsion polymerization from acrylamide, arginine-acrylamide, ferrocene-acrylate, and N,N'-bis(acryloyl)cystamine, followed by surface coating with hyaluronic acid. After targeted delivery into cancer cells, the nanozymes are dissociated by intracellular glutathione to release GOx, which decomposed glucose to generate gluconic acid and H₂ O₂ . Under such acidified conditions, H₂ O₂ efficiently oxidized pendant arginine residues to produce nitric oxide , transformed into a highly toxic hydroxyl radical and superoxide anion via ferrocene-mediated Fenton reaction and Haber-Weiss cycle, and simultaneously generated peroxynitrite anion via reaction between NO and ·O₂ ^- , thus provoking the RONS radical storm to effectively eradicate A549 tumor cells both in vitro and in vivo. This nature-inspired enzyme-chemical dynamic therapy may provide a promising modality for anti-cancer treatment.

Realizing Highly Efficient Sonodynamic Bactericidal Capability through the Phonon-Electron Coupling Effect Using Two-Dimensional Catalytic Planar Defects

Conferring catalytic defects in sonosensitizers is of paramount importance in reinforcing sonodynamic therapy. However, the formation of such 0D defects is governed by the Schottky defect principle. Herein, 2D catalytic planar defects are designed within Ti₃ C₂  sheets to address this challenge. These specific planar slip dislocations with abundant Ti³⁺ species (Ti₃ C₂ -SD(Ti³⁺ )) can yield surface-bound O due to the effective activation of O₂ , thus resulting in a substantial amount of ¹ O₂  generation and the 99.72% ± 0.03% bactericidal capability subject to ultrasound (US) stimulation. It is discovered that the 2D catalytic planar defects can intervene in electron transfer through the phonon drag effect-a coupling effect between surface electrons and US-triggered phonons-that simultaneously contributes to a dramatic decrease in O₂  activation energy from 1.65 to 0.06 eV. This design has achieved a qualitative leap in which the US catalytic site has transformed from 0D to 2D. Moreover, it is revealed that the electron origin, electron transfer, and visible O₂  activation pathway triggered by US can be attributed to the phonon-electron coupling effect. After coating with neutrophil membrane (NM) proteins, the NM-Ti₃ C₂ -SD(Ti³⁺ ) sheets further demonstrate a 6-log₁₀  reduction in methicillin-resistant Staphylococcus aureus burden in the infected bony tissue.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

Defect-Rich Glassy IrTe2 with Dual Enzyme-Mimic Activities for Sono-Photosynergistic-Enhanced Oncotherapy

The complexity, diversity, and heterogeneity of malignant tumors pose a formidable challenge for antitumor therapy. To achieve the goal of significantly enhancing the antitumor effect, nanomedicine-based synergistic therapy is one of the important strategies. Herein, we innovatively report a defect-rich glassy IrTe2 (G-IrTe2) with weak Ir-Te bond strength for synergistic sonodynamic therapy (SDT), chemodynamic therapy (CDT), and mild photothermal therapy (PTT). G-IrTe2 sonosensitizer under ultrasound (US) stimuli exhibits excellent reactive oxygen species (ROS) production performance. Besides, catalase (CAT)-like activity of G-IrTe2 can provide abundant oxygen to enhance the SDT effect. Then, the theoretical calculation verifies that US stimuli can easily make the irregular Ir-Te bond to be broken in amorphous IrTe2 and free electrons will be released to combine with the oxygen and further form singlet oxygen (1O2). Meanwhile, G-IrTe2 with peroxidase (POD)-like activity can also catalyze endogenous H2O2 to produce more ROS for chemodynamic therapy (CDT), which is conducive to better tumor ablation. Furthermore, the ROS produced by sono-/chemodynamic processes can cause mitochondrial dysfunction and further give rise to heat shock protein (HSP) downregulated expression, maximizing the efficiency of mild PTT. Therefore, such glassy IrTe2 with rich defect could be significantly involved in synergistic oncotherapy and then effectively achieve outstanding antitumor efficacy. This study provides a new research idea for expanding the application of inorganic glassy nanomaterials in promoting the therapeutic effect of tumors.

A robust Au@Cu2-xS nanoreactor assembled by silk fibroin for enhanced intratumoral glucose depletion and redox dyshomeostasis

Intracellular redox dyshomeostasis promoted by tumor microenvironment (TME) modulation has become an appealing therapeutic target for cancer management. Herein, a dual plasmonic Au/SF@Cu_2-xS nanoreactor (abbreviation as ASC) is elaborately developed by covalent immobilization of sulfur defective Cu_2-xS nanodots onto the surface of silk fibroin (SF)-capped Au nanoparticles. Tumor hypoxia can be effectively alleviated by ASC-mediated local oxygenation, owing to the newfound catalase-mimic activity of Cu_2-xS. The semiconductor of Cu_2-xS with narrow bandgap energy of 2.54 eV enables a more rapid dissociation of electron-hole (e^-/h⁺) pair for a promoted US-triggered singlet oxygen (¹O₂) generation, in the presence of Au as electron scavenger. Moreover, Cu_2-xS is devote to Fenton-like reaction to catalyze H₂O₂ into ·OH under mild acidity and simultaneously deplete glutathione to aggravate intracellular oxidative stress. In another aspect, Au nanoparticles with glucose oxidase-mimic activity consumes intrinsic glucose, which contributes to a higher degree of oxidative damage and energy exhaustion of cancer cells. Importantly, such tumor starvation and ¹O₂ yield can be enhanced by Cu_2-xS-catalyzed O₂ self-replenishment in H₂O₂-rich TME. ASC-initiated M1 macrophage activation and therapy-triggered immunogenetic cell death (ICD) favors the systematic tumor elimination by eliciting antitumor immunity. This study undoubtedly enriches the rational design of SF-based nanocatalysts for medical utilizations.

Integration of Silica Nanorattles with Manganese-Doped In2S3/InOOH to Enable Ultrasound-Mediated Tumor Theranostics

As a result of their radiation-free nature and deep-penetration ability, tumor theranostics mediated by ultrasound have become increasingly recognized as a modality with high potential for translation into clinical cancer treatment. The effective integration of ultrasound imaging and sonodynamic therapy (SDT) into one nanoplatform remains an enormous challenge yet to be fully resolved. Here, a novel theranostic system, consisting of rattle-type SiO₂ (r-SiO₂) loaded with Mn-doped In₂S₃/InOOH (SMISO), was designed and synthesized to enable an improved ultrasound imaging-guided therapy. With Mn-doped In₂S₃/InOOH (MISO) and a heterojunction structure, this novel sonosensitizer facilitates the generation of reactive oxygen species (ROS) for SDT. By coupling interfaces between the shell and core in rattle-type SiO₂, multiple reflections/scattering are generated, while MISO has high acoustic impedance. By integrating r-SiO₂ and MISO, the SMISO composite nanoparticles (NPs) increase the acoustic reflection and provide enhanced contrast for ultrasound imaging. Through the effective accumulation in tumors, which was monitored by B-mode ultrasound imaging in vivo, SMISO composite NPs effectively inhibited tumor growth without adverse side effects under ultrasound irradiation treatment. This work therefore provides a new approach to integrate a novel gas-free ultrasound contrast agent and a semiconductor sonosensitizer for cancer theranostics.

Hollow CoP@N-Carbon Nanospheres: Heterostructure and Glucose-Enhanced Charge Separation for Sonodynamic/Starvation Therapy

Sonodynamic therapy (SDT) can be described as ultrasonic (US) catalysis. Adequate charge separation is considered as effective means to promote reactive oxygen species (ROS). Here, hollow CoP@N-carbon@PEG (CPCs@PEG) nanospheres (∼60 nm) are prepared as sonosensitizers, showing greater ROS generation than pure CoP@PEG under US irradiation. Both ¹O₂ and ·O₂^- are activation species that are determined by O₂ and electrons. The great SDT performance of CPCs@PEG is ascribed to the heterostructure which promotes the separation and transfer for US-generated electrons and holes. In addition, holes can be further captured by endogenous glucose that is in favor of electron aggregation and ROS generation. Moreover, the consumption of glucose would decrease intracellular ATP for starvation therapy. Given the higher oxidation ability of Co³⁺, CPCs@PEG nanospheres possess catalase (CAT) activity to convert H₂O₂ into O₂ for assisting ROS generation. Moreover, they also can oxidize glutathione (GSH) as a mimic GSH oxidase to break intratumor redox balance, facilitating oxidative stress. More importantly, the nanocomposites reveal good degradation ability dominated by the oxidation from insoluble phosphide into soluble phosphate, accelerating elimination via urine and feces within 14 days. CPCs@PEG nanospheres integrate the above effects not only to reveal great tumor inhibition ability but also to excite immune activation for anticancer.

Live bio-nano-sonosensitizer targets malignant tumors in synergistic therapy

Sonosensitizers that can increase the concentration of reactive oxygen species (ROS) within a tumor microenvironment is a high priority for sonodynamic therapy (SDT). In this study, a functionalized, smart nanosonosensitizer based on Au-RuO₂ nanoparticles (NPs) and selenium nanoparticles (Se NPs) that were electrostatically self-assembled onto the surface of Listeria innocua (LI) was used to create Bac@ARS. Au NPs provided the core in which RuO₂ was deposited to form Au-RuO₂ NPs. Additionally, the underlying properties of the Au NPs and Se NPs were used to optimize the sonosensitivity performance. Compared with pristine RuO₂ NPs, Bac@ARS exhibits highly efficient ROS-producing activity. Furthermore, Bac@ARS remodeled the hypoxic tumor microenvironment, enabling overproduction of ROS. Importantly, Bac@ARS exploits the natural tropism of LI to selectively accumulate in tumors, which improved the treatment precision at hypoxic tumor sites after sonodynamic activation. However, the activity of LI was greatly reduced after ultrasound (US) irradiation, ensuring the biosafety of Bac@ARS. Bac@ARS was also used to monitor tumors, in real time, using photoacoustic imaging of the gold-based nanoparticles. Therefore, Bac@ARS is a promising microbial sonosensitizer providing a new platform for the optimization of sonosensitizers for tumor treatment. STATEMENT OF SIGNIFICANCE: A bio-nano-sonosensitizer was designed using a Au nanoparticle (NP) core modified with RuO₂ NPs. The Au-RuO₂ NPs together with Se-NPs are attached via electrostatic adsorption to a live bacterium Listeria innocua (LI), creating Bac@ARS. The role of the NPs was to optimize the sonosensitivity performance at the target tumor site. Bac@ARS reshaped the tumor microenvironment and overcame tumor hypoxia leading to ROS overproduction. This activated a potent ICD-mediated cellular immunity and anti-tumor activity. Importantly, Bac@ARS exploited the natural tropism of LI to selectively accumulate in tumors, resulting in more precise delivery of the therapeutic effect while exhibiting reduced effects on healthy tissues.

Defective Homojunction Porphyrin-Based Metal-Organic Frameworks for Highly Efficient Sonodynamic Therapy

Sonodynamic therapy (SDT) with non-invasiveness and high tissue-penetrating ability has attracted widespread interest in treating deep-seated tumors or infections. To enhance the treatment efficacy of SDT, the development of high-efficiency and stable sonosensitizers are still needed. Herein, a defective homojunction porphyrin-based metal-organic framework (MOF) with greatly enhanced sonocatalytic ability is easily prepared and used for SDT of osteomyelitis infected by methicillin-resistant Staphylococcus aureus (MRSA). Acetic acid and benzoic acid are chosen as modulators during the hydrothermal synthesis of porphyrin-based MOF. It is found that the crystal structure of MOF shifts from PCN-222 to PCN-224 as the amount of acetic acid increases. Interestingly, the defective PCN (D-PCN) contains a two-phase homojunction structure of PCN-222/PCN-224. The sonocatalytic reactive oxygen species production presents a volcano-type trend with increased acetic acid, among which D-PCN-2 with more content of PCN-224 has the best sonocatalytic antibacterial ability. The reduced band gap introduced a defect, and type-II homojunction structures of D-PCN-2 improve the separation of the ultrasound-triggered electron hole, which significantly enhances the SDT effect. Through a mixed linker approach, this work develops a new defect-induced homojunction MOF with great performance for SDT of MRSA-infected osteomyelitis.

Ag-Doped Metal-Organic Frameworks' Heterostructure for Sonodynamic Therapy of Deep-Seated Cancer and Bacterial Infection

Metal-organic frameworks (MOF) have attracted great potential in sonodynamic therapy (SDT) owing to large sonosensitizers' loading and fast reactive oxygen species' (ROS) diffusion; however, the low ligand-to-metal charge transfer efficiency sharply impairs the SDT effect. Herein, we report the design of MIL@Ag heterostructures with high electron-hole pairs separation efficiency and enhanced diverse ROS generation ability for deep-seated cancer treatment and bacterial infection. The MIL@Ag heterostructure is composed of Ti-based MOFs (named MIL), on which are in situ assembled silver nanoparticles (Ag NPs). The electrochemical experiments and density functional theory calculations verify that the introduction of Ag NPs can significantly improve the electron transfer efficiency and O2 adsorption capacity of MIL. Under ultrasound irradiation, the doped Ag NPs can trap the activated electrons from MIL to reduce surrounding O2 and produce superoxide radicals (•O2-), while the activated holes enable oxidizing H2O to produce hydroxyl radicals (•OH). Thus, they efficiently improve the therapeutic efficiency of SDT. MIL@Ag-PEG-mediated SDT implements A549 cancer cells' killing under a tissue barrier of 2 cm and eradicates the bacterial infection of Staphylococcus aureus, thus promoting wound healing. Therefore, MIL@Ag-PEG provides a promising strategy for augmenting SDT performance by rational heterostructure design of sonosensitizers.

Interfacial Mo, W-Conjugated Polarization, and Oxygen Vacancies of MoO2/WO3 in Enhanced Microwave Therapy for MRSA-Induced Osteomyelitis

Deep tissue infection, such as osteomyelitis, caused by methicillin-resistant Staphylococcus aureus (MRSA) infection, poses a serious threat to public health and cannot be effectively treated by antibiotics. In this study, we report a microwave (MW)-responsive MoO₂/WO₃ heterojunction that can be utilized to effectively treat MRSA-infected osteomyelitis under MW irradiation because of the enhanced MW thermal effect and MW catalysis of the composite. The underlying mechanism is as follows: A myriad of oxygen vacancies forms on the surface of MoO₂ and WO₃ by deoxidization effect with hydrogen from the decomposition of sodium borohydride, which induces a mass of free electrons on the surface of the composite and consequently promotes a localized surface plasmon resonance effect (LSPR) under MW irradiation. Furthermore, the conjugation of Mo and W at the interface enhances the LSPR effect. Thus, the LSPR effect not only induces the formation of radical oxygen species, thereby enhancing MW catalysis, but also results in the formation of an interfacial electrical field, which strengthens dipole polarization through synergistic action with oxygen vacancies and contributes to better MW thermal effects. The characteristics of MoO₂/WO₃ prove to be promising for the treatment of deep-tissue infections under MW irradiation.

Effective Sonosensitizer Delivery by Redox Sensitive Nanoparticles for Prostate Cancer Sonodynamic Therapy via Amplifying Oxidative Stress and Peroxidation

Sonodynamic therapy (SDT), a novel noninvasive therapeutic modality, provides many noteworthy benefits by generating reactive oxygen species (ROS). However, water-insoluble sonosensitizer delivery strategies have continuously underperformed because of unavoidable toxicity and a short circulation time. In this study, l-cystine derivative-based biocompatible nanoparticles (NPs) that can be used in SDT and induce limited cytotoxicity are designed and synthesized. After ultrasonic (US) irradiation, these sonosensitizer-loaded NPs show highly efficient sonodynamic performance that leads to cytotoxic ROS production. The ability to stop and start ROS generation induced by US irradiation enables accurate temporal and spatial control. In vivo and in vitro experiments are systematically performed to investigate the effects of this system on tumors, and the results indicate remarkable tumor suppression via markedly high persistent oxidative stress that induces peroxidation and endoplasmic reticulum stress. Thus, this novel temporally and spatially controllable ROS generation platform offers a safe and effective theranostic strategy for prostate cancer treatment.

Guanidinium-Decorated Nanostructure for Precision Sonodynamic-Catalytic Therapy of MRSA-Infected Osteomyelitis

Osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection is difficult to eradicate and can even be life-threatening. Given that the infection is persistent and deep-seated in the bone tissue, controlled and efficient treatment of osteomyelitis remains challenging. Herein, an activatable nanostructure (Au/TNT@PG) is presented for synergistic sonodynamic-catalytic therapy of MRSA-infected osteomyelitis. The Au/TNT@PG backbone is obtained by conjugating a guanidinium-rich polymer (PG), a component that penetrates the biofilm matrix, onto ultrasound (US)-absorbing gold-doped titanate nanotubes (Au/TNTs). Under deep-penetrating US irradiation, the nanocomposite generates ¹ O₂ for sonodynamic therapy and catalyzes the decomposition of endogenous H₂ O₂ into toxic •OH in the acidic infection microenvironment for catalytic therapy, leading to bacterial cell death. Its robust antibacterial effectiveness is attributable to its bacteria-capturing ability, the biofilm penetrability of positively charged guanidinium, and the subsequent synergistic effect of sonodynamic-catalytic action of Au/TNT. Such a remotely controlled approach potentiates the polarization of macrophages to M2-type while suppressing the M1-type, leading to topical inflammation resolution and enhanced osteoblast proliferation and differentiation to inhibit bone loss. Therefore, this study provides a generic nanotherapeutic approach for efficient sonodynamic-catalytic therapy with respect to osteomyelitis.

ROS generation strategy based on biomimetic nanosheets by self-assembly of nanozymes

Reactive oxygen species (ROS) play an important role in physiology and have been applied in tumor therapy. However, insufficient endogenous H₂O₂ and hypoxia in cancer cells can lead to limited ROS production and poor therapeutic efficacy. Herein, we develop a biomimetic nanosheet material based on the self-assembly of nanozymes that could supply H₂O₂ under acidic conditions and catalyze a cascade of intracellular biochemical reactions to produce ROS under both normoxic and hypoxic conditions without any external stimuli. In this system, the copper peroxide nanosheets (CPNS), which are pH-responsive, were prepared through coordination of H₂O₂ to Cu²⁺ and then modified using ultrafine Pt NPs to form CPNS@Pt. The CPNS could decompose under acidic conditions, allowing the simultaneous release of Fenton catalytic Cu²⁺ and H₂O₂ accompanied by a Fenton-type reaction between them. On the other hand, Pt NPs were also released. The released Pt NPs behave as an oxidase mimic and catalase mimic. In this way, the well-defined CPNS@Pt can not only relieve hypoxic conditions but also generate ROS to induce cell apoptosis, thereby paving the way for the development of a nanozyme with multienzyme activity as a therapeutic strategy.

A tumor microenvironment-activated metal-organic framework-based nanoplatform for amplified oxidative stress-induced enhanced chemotherapy

Engineering a highly tumor microenvironment-responsive nanoplatform toward effective chemotherapy has always been a challenge in targeted cancer treatment. Metal-organic frameworks are a promising delivery system to reformulate previously approved drugs for enhanced chemotherapy, such as disulfiram (DSF). Herein, a tumor microenvironment-activated metal-organic framework-based nanoplatform DSF@MOF-199@FA has been fabricated to realize amplified oxidative stress-induced enhanced chemotherapy. Our results unveil that the copper ions and DSF released by DSF@MOF-199@FA in an acidic environment can be converted into toxic bis(N, N-diethyl dithiocarbamate) copper and then induce cell apoptosis. Simultaneously, we determined that the apoptosis outcome is further promoted by amplified oxidative stress through effective generation of reactive oxygen species and GSH elimination. In conclusion, this work provides a promising platform for effective anticancer treatment.

A Novel Biodegradable Nanoplatform for Tumor Microenvironments Responsive Bimodal Magnetic Resonance Imaging and Sonodynamic/Ion Interference Cascade Therapy

The unsatisfactory therapeutic effect and long-term adverse effect markedly prevent inorganic nanomaterials from clinical transformation. In light of this, we developed a novel biodegradable theranostic agent (MnCO₃:Ho³⁺@DOX/Ca₃(PO₄)₂@BSA, HMCDB) based on the sonosensitizer manganese carbonate (MnCO₃) coating with calcium phosphate (Ca₃(PO₄)₂) and simultaneously loaded it with the chemotherapeutic drug doxorubicin (DOX). Due to the mild acidity of the tumor microenvironment (TME), the Ca₃(PO₄)₂ shell degraded first, releasing substantial quantities of calcium ions (Ca²⁺) and DOX. Meanwhile, with the ultrasound (US) irradiation, MnCO₃ produced enough reactive oxygen species (ROS) to cause oxidative stress in the cells, resulting in accumulation of Ca²⁺. Consequently, the cascade effect significantly amplified the therapeutic effect. Importantly, the nanocomposite can be completely degraded and cleared from the body, demonstrating that it was a promising theranostic agent for tumor therapy. Furthermore, the doped holmium ions (Ho³⁺) and in situ generation of manganese ions (Mn²⁺) in TME endow the nanoagent with the ability for tumor-specific bimodality T₁/T₂-weighted magnetic resonance imaging (MRI). This novel nanoplatform with low toxicity and biodegradability holds great potential for cancer diagnosis and treatment.

Amplifying Dendritic Cell Activation by Bioinspired Nanometal Organic Frameworks for Synergistic Sonoimmunotherapy

Despite recent advancements of sonodynamic therapy (SDT) in cancer immunotherapy, challenges have yet to be surmounted to further boost its immunotherapeutic efficacy due to the low-level tumor antigens presentation of dendritic cells (DCs). Cell membrane camouflaged-nanoparticles can integrate the neoantigens of the cancer cell membrane with the multifunctionalities of synthetic nanocores. Herein, sono-responsive nanoparticles coated with DC-targeted antibody chimeric cancer cell membrane are investigated for multimodal therapy. The nanometal organic frameworks (MOFs) that respond to ultrasound are loaded successfully inside the vesicles displaying an anti-DEC205 antibody. The anti-DEC205 chimeric vesicles can directly target and activate DCs, promote tumor antigens cross-presentation, and then produce a cascade amplified T-cell immune response. Upon deep tissue-penetrating sonication, AMR-MOF@AuPt generates large amounts of reactive oxygen species that directly kill cancer cells, further initiating an anti-cancer T cell immune response. Such synergistic sono-immunotherapies effectually inhibit tumor growth and induce strong systemic and long-term immune memory against cancer recurrence and distant metastasis. The authors findings provide DCs and tumor cells of a dual active-targeting cell membrane-coated sono-immunotherapeutic nanoplatform for cancer therapy.