Nanoscale Metal-Organic Frameworks Combined with Metal Nanoparticles and Metal Oxide/Peroxide to Relieve Tumor Hypoxia for Enhanced Photodynamic Therapy

State-of-the-Art, Insights, and Perspectives for MOFs-Nanocomposites and MOF-Derived (Nano)Materials

Composite structures created from metal‒organic framework (MOF) matrices are reviewed in this work. Depending on the nature of the second component apart from the MOF platform, several synergistic properties may arise; at the same time, the initial features of the single constituent materials are usually maintained, and individual shortcomings are mitigated. Currently, timely energy and environmental challenges necessitate the quest for more advanced materials and technologies. Significant developments in MOF-nanocomposites have enabled their application across a wide range of modern and traditional fields. This review demonstrates in an exhaustive and critical way a broad range of MOF-based nanocomposites, namely, MOF/perovskite nanoparticles (NPs), MOF/metal (non-iron) oxide NPs, MOF/Fe3O4 NPs, MOF/metal chalcogenide NPs, MOF/metal NPs, and MOF/carbon-based materials, as well as nanocomposites of MOFs with other semiconductor NPs. Key points related to the synthesis, characterization, and applications of these materials are provided. Depending on their configuration, the composites under discussion can be applied in domains such as photoelectrochemical sensing, antibiotic/dye degradation, optoelectronics, photovoltaics, catalysis, solar cells, supercapacitors, batteries, water remediation, and drug loading. Sometimes, MOFs can undergo certain processes (e.g. pyrolysis) and act as precursors for composite materials with appealing characteristics. Therefore, a special section in the manuscript is devoted to MOF-derived NP composites. Toward the end of the text, we conclude while also describing the challenges and possibilities for further investigations in the umbrella of material categories analyzed herein. Despite the progress achieved, key questions remain to be answered regarding the relationships among the morphology, properties, and polyvalent activity of these materials. The present work aims to shed light on most of their aspects and innovative prospects, facilitating a deeper comprehension of the underlying phenomena, functionality, and mechanistic insights governing their behavior.

Recent advances in polydopamine-coated metal-organic frameworks for cancer therapy

The creation and development of classical multifunctional nanomaterials are crucial for the advancement of nanotherapeutic treatments for tumors. Currently, metal-organic frameworks (MOFs) modified with polydopamine (PDA) are at the forefront of nanomedicine research, particularly in tumor diagnostics and therapy, owing to their exceptional biocompatibility, expansive specific surface area, multifaceted functionalities, and superior photothermal properties, which led to significant advancements in anti-tumor research. Consequently, a range of anti-cancer strategies has been devised by leveraging the exceptional capabilities of MOFs, including intelligent drug delivery systems, photodynamic therapy, and photothermal therapy, which are particularly tailored for the tumor microenvironment. In order to gain deeper insight into the role of MOFs@PDA in cancer diagnosis and treatment, it is essential to conduct a comprehensive review of existing research outcomes and promptly analyze the challenges associated with their biological applications. This will provide valuable perspectives on the potential of MOFs@PDA in clinical settings.

Optimization of Metal-Based Nanoparticle Composite Formulations and Their Application in Wound Dressings

Metal-based nanoparticles (MNPs) have great potential for applications in wound healing and tissue engineering, and due to their unique structures, high bioactivities, and excellent designability characteristics, an increasing number of studies have been devoted to modifying these species to generate novel composites with desirable optical, electrical, and magnetic properties. However, few systematic and detailed reviews have been performed relating to the modification approaches available for MNPs and their resulting composites. In this review, a comprehensive summary is performed regarding the optimized modification formulations of MNPs for application in wound dressings, and the techniques used to prepare composite wound dressings are discussed. In addition, the safety profiles of the novel nanocomposite formulations and the limitations of the reported systems are evaluated. More importantly, a number of solution strategies are proposed to address these limitations. Overall, this review provides new ideas for the design of MNPs to facilitate their application in the field of skin tissue repair, and also looks into the future direction of MNPs in the biomedical field.

Chlorin e6: a promising photosensitizer of anti-tumor and anti-inflammatory effects in PDT

Photodynamic therapy (PDT) involves the activation of photosensitizers (PSs) by visible laser light at the target site to catalyze the production of reactive oxygen species, resulting in tumor cell death and blood vessel closure. The efficacy of PDT depends on the PSs, the amount of oxygen, and the intensity of the excitation laser. PSs have been extensively researched, and great efforts have been made to develop an ideal photosensitizer. Chlorin-e6 is an FDA-approved second-generation PSs that has attracted widespread research interest in the medical field, especially with respect to antitumor and anti-inflammatory activity. Chlorin-e6 possesses the advantages of a large absorption coefficient, high strength, low residue in the body, and relatively high safety and thus has promising application prospects. Here we review the use of chlorin-e6 in PDT and discuss the prospects of further development of this technology.

Metal-organic framework (MOF)-bioactive glass (BG) systems for biomedical applications - A review

In recent years, metal-organic frameworks (MOFs) have emerged as promising materials for biomedical applications, owing to their superior chemical versatility, unique textural properties and enhanced mechanical properties. However, their fast and uncontrolled degradation, together with the reduced bioactivity have restricted their clinical potential. To overcome these limitations, MOFs can be synergistically combined with other materials, such as bioactive glasses (BGs), known for their bioactivity and therapeutic ion releasing capabilities. Besides comparing MOFs and BGs, this review aims to present the latest achievements of different MOFs/BGs materials, with a particular focus on their complementary and synergistic properties. Key findings show that combining MOFs and BGs enables the development of composite materials with superior physicochemical and biological properties. Moreover, by choosing appropriate processing techniques, BGs and MOFs can be fabricated as scaffolds or coatings with fast mineralization ability and high corrosion resistance. In addition, incorporation of MOFs/BGs in hydrogels improves mechanical stability, bioactivity and antibacterial properties, while maintaining biocompatibility. The mechanisms behind the antibacterial properties, likely coming from the release of metal ions and organic ligands, are also discussed. Overall, this review highlights the current research directions and emerging trends in the synergistic use of MOFs and BGs for biomedical applications, which represents a novel strategy for developing a new family of advanced therapeutic materials.

pH-responsive oxygen self-sufficient smart nanoplatform for enhanced tumor chemotherapy and photodynamic therapy

Premature drug release in chemotherapy and hypoxic conditions in photodynamic therapy (PDT) are perplexing problems in tumor treatment. Thus, it is of great significance to develop the novel therapeutic system with controllable drug release and effective oxygen generation. Herein, a pH-responsive oxygen self-sufficient smart nanoplatform (named DHCCC), integrating hollow mesoporous silica nanoparticles (HMSNs), chitosan (CS), doxorubicin hydrochloride (DOX), chlorin e6 (Ce6) and catalase (CAT), is fabricated to enhance the tumor therapeutic efficacy efficiently through avoiding premature drug release and mitigating hypoxia of tumor microenvironment (TME). The drug DOX can be efficiently loaded into the HMSNs with large cavity and be controllable released because of the pH responsiveness of CS to the weak acidic TME, thereby elevating the chemotherapy efficacy. Meanwhile, CAT can catalyze the decomposition of endogenous hydrogen peroxide in situ generating oxygen to alleviate the hypoxia and enhance the PDT efficiency considerably. In vitro and in vivo results demonstrate that the combined chemo-photodynamic therapy based on the DHCCC nanoplatform exerts more effective antitumor efficacy than chemotherapy or PDT alone. The current study provides a promising inspiration to construct the pH-responsive oxygen self-sufficient smart nanomedicine with potentials to prevent premature drug leakage and overcome hypoxia for efficient tumor therapy.

Self-supply of hydrogen peroxide by a bimetal-based nanocatalytic platform to enhance chemodynamic therapy for tumor treatment

The tumor microenvironment (TME) is characterized by low pH, hypoxia, and overexpression of glutathione (GSH). Owing to the complexity of tumor pathogenesis and the heterogeneity of the TME, achieving satisfactory efficacy with a single treatment method is difficult, which significantly impedes tumor treatment. In this study, composite nanoparticles of calcium-copper/alginate-hyaluronic acid (HA) (CaO2-CuO2@SA/HA NC) with pH and GSH responsiveness were prepared for the first time through a one-step synthesis using HA as a targeting ligand. Nanoparticles loaded with H2O2can enhance the chemodynamic therapy effects. Simultaneously, Cu2+can generate oxygen in the TME and alleviate hypoxia in tumor tissue. Cu2+and H2O2undergo the Fenton reaction to produce cytotoxic hydroxyl radicals and Ca2+ions, which enhance the localization and clearance of nanoparticles in tumor cells. Additionally, HA and sodium alginate (SA) were utilized to improve the targeting and biocompatibility of the nanoparticles. Fourier transform infrared, x-ray diffraction, dynamic light scattering, SEM, transmission electron microscope, and other analytical methods were used to investigate their physical and chemical properties. The results indicate that the CaO2-CuO2@SA/HA NC prepared using a one-step method had a particle size of 220 nm, a narrow particle size distribution, and a uniform morphology. The hydrogen peroxide self-supplied nanodrug delivery system exhibited excellent pH-responsive release performance and glutathione-responsive •OH release ability while also reducing the level of reactive oxide species quenching.In vitrocell experiments, no obvious side effects on normal tissues were observed; however, the inhibition rate of malignant tumors HepG2 and DU145 exceeded 50%. The preparation of CaO2-CuO2@SA/HA NC nanoparticles, which can achieve both chemokinetic therapy and ion interference therapy, has demonstrated significant potential for clinical applications in cancer therapy.

Nanozyme Decorated Metal-Organic Framework Nanosheet for Enhanced Photodynamic Therapy Against Hypoxic Tumor

INTRODUCTION

Photodynamic therapy (PDT) has attracted increasing attention in the clinical treatment of epidermal and luminal tumors. However, the PDT efficacy in practice is severely impeded by tumor hypoxia and the adverse factors associated with hydrophobic photosensitizers (PSs), including low delivery capacity, poor photoactivity and limited ROS diffusion. In this study, Pt nanozymes decorated two-dimensional (2D) porphyrin metal-organic framework (MOF) nanosheets (PMOF@HA) were fabricated and investigated to conquer the obstacles of PDT against hypoxic tumors.

MATERIALS AND METHODS

PMOF@HA was synthesized by the coordination of transition metal iron (Zr4+) and PS (TCPP), in situ generation of Pt nanozyme and surface modification with hyaluronic acid (HA). The abilities of hypoxic relief and ROS generation were evaluated by detecting the changes of O2 and 1O2 concentration. The cellular uptake was investigated using flow cytometry and confocal laser scanning microscopy. The SMMC-7721 cells and the subcutaneous tumor-bearing mice were used to demonstrate the PDT efficacy of PMOF@HA in vitro and in vivo, respectively.

RESULTS

Benefiting from the 2D structure and inherent properties of MOF materials, the prepared PMOF@HA could not only serve as nano-PS with high PS loading but also ensure the rational distance between PS molecules to avoid aggregation-induced quenching, enhance the photosensitive activity and promote the rapid diffusion of generated radical oxide species (ROS). Meanwhile, Pt nanozymes with catalase-like activity effectively catalyzed intratumoral overproduced H2O2 into O2 to alleviate tumor hypoxia. Additionally, PMOF@HA, with the help of externally coated HA, significantly improved the stability and increased the cell uptake by CD44 overexpressed tumor cells to strengthen O2 self-supply and PDT efficacy.

CONCLUSION

This study provided a new strategy of integrating 2D porphyrin MOF nanosheets with nanozymes to conquer the obstacles of PDT against hypoxic tumors.

Enhancing cancer immunotherapy: Nanotechnology-mediated immunotherapy overcoming immunosuppression

Immunotherapy is an important cancer treatment method that offers hope for curing cancer patients. While immunotherapy has achieved initial success, a major obstacle to its widespread adoption is the inability to benefit the majority of patients. The success or failure of immunotherapy is closely linked to the tumor's immune microenvironment. Recently, there has been significant attention on strategies to regulate the tumor immune microenvironment in order to stimulate anti-tumor immune responses in cancer immunotherapy. The distinctive physical properties and design flexibility of nanomedicines have been extensively utilized to target immune cells (including tumor-associated macrophages (TAMs), T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated fibroblasts (TAFs)), offering promising advancements in cancer immunotherapy. In this article, we have reviewed treatment strategies aimed at targeting various immune cells to regulate the tumor immune microenvironment. The focus is on cancer immunotherapy models that are based on nanomedicines, with the goal of inducing or enhancing anti-tumor immune responses to improve immunotherapy. It is worth noting that combining cancer immunotherapy with other treatments, such as chemotherapy, radiotherapy, and photodynamic therapy, can maximize the therapeutic effects. Finally, we have identified the challenges that nanotechnology-mediated immunotherapy needs to overcome in order to design more effective nanosystems.

Advances in H2O2-supplying materials for tumor therapy: synthesis, classification, mechanisms, and applications

Hydrogen peroxide (H2O2) as a reactive oxygen species produced by cellular metabolism can be used in antitumor therapy. However, the concentration of intracellular H2O2 limits its application. Some materials could enhance the concentration of intracellular H2O2 to strengthen antitumor therapy. In this review, the recent advances in H2O2-supplying materials in terms of promoting intracellular H2O2 production and exogenous H2O2 supply are summarized. Then the mechanism of H2O2-supplying materials for tumor therapy is discussed from three aspects: reconstruction of the tumor hypoxia microenvironment, enhancement of oxidative stress, and the intrinsic anti-tumor ability of H2O2-supplying materials. In addition, the application of H2O2-supplying materials for tumor therapy is discussed. Finally, the future of H2O2-supplying materials is presented. This review aims to provide a novel idea for the application of H2O2-supplying materials in tumor therapy.

Synergistic Regulation of Targeted Organelles in Tumor Cells to Promote Photothermal-Immunotherapy Using Intelligent Core-Satellite-Like Nanoparticles for Effective Treatment of Breast Cancer

The normal operation of organelles is critical for tumor growth and metastasis. Herein, an intelligent nanoplatform (BMAEF) is fabricated to perform on-demand destruction of mitochondria and golgi apparatus, which also generates the enhanced photothermal-immunotherapy, resulting in the effective inhibition of primary and metastasis tumor. The BMAEF has a core of mesoporous silica nanoparticles loaded with brefeldin A (BM), which is connected to ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA) and folic acid co-modified gold nanoparticles (AEF). During therapy, the BMAEF first accumulates in tumor cells via folic acid-induced targeting. Subsequently, the schiff base/ester bond cleaves in lysosome to release brefeldin A and AEF with exposed EGTA. The EGTA further captures Ca2+ to block ion transfer among mitochondria, endoplasmic reticulum, and golgi apparatus, which not only induced dysfunction of mitochondria and golgi apparatus assisted by brefeldin A to suppress both energy and material metabolism against tumor growth and metastasis, but causes AEF aggregation for tumor-specific photothermal therapy and photothermal assisted immunotherapy. Moreover, the dysfunction of these organelles also stops the production of BMI1 and heat shock protein 70 to further enhance the metastasis inhibition and photothermal therapy, which meanwhile triggers the escape of cytochrome C to cytoplasm, leading to additional apoptosis of tumor cells.

Chitosan- and hyaluronic acid-based nanoarchitectures in phototherapy: Combination cancer chemotherapy, immunotherapy and gene therapy

Cancer phototherapy has been introduced as a new potential modality for tumor suppression. However, the efficacy of phototherapy has been limited due to a lack of targeted delivery of photosensitizers. Therefore, the application of biocompatible and multifunctional nanoparticles in phototherapy is appreciated. Chitosan (CS) as a cationic polymer and hyaluronic acid (HA) as a CD44-targeting agent are two widely utilized polymers in nanoparticle synthesis and functionalization. The current review focuses on the application of HA and CS nanostructures in cancer phototherapy. These nanocarriers can be used in phototherapy to induce hyperthermia and singlet oxygen generation for tumor ablation. CS and HA can be used for the synthesis of nanostructures, or they can functionalize other kinds of nanostructures used for phototherapy, such as gold nanorods. The HA and CS nanostructures can combine chemotherapy or immunotherapy with phototherapy to augment tumor suppression. Moreover, the CS nanostructures can be functionalized with HA for specific cancer phototherapy. The CS and HA nanostructures promote the cellular uptake of genes and photosensitizers to facilitate gene therapy and phototherapy. Such nanostructures specifically stimulate phototherapy at the tumor site, with particle toxic impacts on normal cells. Moreover, CS and HA nanostructures demonstrate high biocompatibility for further clinical applications.

Metal-Organic Framework PCN-224 Combined Cobalt Oxide Nanoparticles for Hypoxia Relief and Synergistic Photodynamic/Chemodynamic Therapy

Photodynamic therapy (PDT) and chemodynamic therapy (CDT) are promising tumor treatments mediated by reactive oxygen species (ROS), which have the advantages of being minimally invasive. However, the hypoxia of tumor microenvironment and poor target ability often reduce the therapeutic effect. Here we propose a tumor targeted nanoplatform PCN-224@Co3O4-HA for enhanced PDT and synergistic CDT, constructed by hyaluronate-modified Co3O4 nanoparticles decorated metal-organic framework PCN-224. Co3O4 can catalyze the decomposition of highly expressed H2O2 in tumor cells to produce oxygen and alleviate the problem of hypoxia. It can also produce hydroxyl radicals according to the Fenton-like reaction for chemical dynamic therapy, significantly improving the therapeutic effect. The cell survival experiment showed that after in vitro treatment, 4T1 and MCF-7 cancer cells died in a large area under the anaerobic state, while the survival ability of normal cell L02 was nearly unchanged. This result effectively indicated that PCN-224@Co3O4-HA could effectively relieve tumor hypoxia and improve the effect of PDT and synergistic CDT. Cell uptake experiments showed that PCN-224@Co3O4-HA had good targeting properties and could effectively aggregate in tumor cells. In vivo experiments on mice, PCN-224@Co3O4-HA presented reliable biosafety performance, and can cooperate with PDT and CDT therapy to prevent the growth of tumor.

Biogated mesoporous silica nanoagents for inhibition of cell migration and combined cancer therapy

Migration is an initial step in tumor expansion and metastasis; suppressing cellular migration is beneficial to cancer therapy. Herein, we designed a novel biogated nanoagents that integrated the migration inhibitory factor into the mesoporous silica nanoparticle (MSN) drug delivery nanosystem to realize cell migratory inhibition and synergistic treatment. Antisense oligonucleotides (Anti) of microRNA-330-3p, which is positively related with cancer cell proliferation, migration, invasion, and angiogenesis, not only acted as the locker for blocking drugs but also acted as the inhibitory factor for suppressing migration via gene therapy. Synergistic with gene therapy, the biogated nanoagents (termed as MSNs-Gef-Anti) could achieve on-demand drug release based on the intracellular stimulus-recognition and effectively kill tumor cells. Experimental results synchronously demonstrated that the migration suppression ability of MSNs-Gef-Anti nanoagents (nearly 30%) significantly contributed to cancer therapy, and the lethality rate of the non-small-cell lung cancer was up to 70%. This strategy opens avenues for realizing efficacious cancer therapy and should provide an innovative way for pursuing the rational design of advanced nano-therapeutic platforms with the combination of cancer cell migratory inhibition.

Chiral cysteine-copper ion-based assemblies for improved phototherapy

Phototherapy, encompassing photothermal therapy and photodynamic therapy, is gaining attention as an appealing cancer treatment modality. To enhance its clinical implementation, a comprehensive exploration of the pivotal factors influencing phototherapy is warranted. In this study, the L/d-cysteine (Cys)-copper ion (Cu2+) chiral nanoparticles, through the assembly of L/d-Cys-Cu2+ coordination complexes, were constructed. We found that these nanoparticles interacted with chiral liposomes in a chirality-dependent manner, with d-Cys-Cu2+ nanoparticles exhibiting more than three times stronger binding affinity than l-Cys-Cu2+ nanoparticles. Furthermore, we demonstrated that the d-Cys-Cu2+ nanoparticles were more efficiently internalized by Hela cells in contrast with l-Cys-Cu2+. On this basis, indocyanine green (ICG), acting as both photothermal and photodynamic agent, was encapsulated into L/d-Cys-Cu2+ nanoparticles. Experimental results showed that the l-Cys-Cu2+-ICG and d-Cys-Cu2+-ICG nanoparticles displayed almost identical photothermal performance and singlet oxygen (1O2) generation capability in aqueous solution. However, upon laser irradiation, the d-Cys-Cu2+-ICG nanoparticles achieved enhanced anti-tumor effects compared to l-Cys-Cu2+-ICG due to their chirality-promoted higher cellular uptake efficiency. These findings highlight the crucial role of chirality in phototherapy and provide new perspectives for engineering cancer therapeutic agents.