Immobilization of nano Cu-MOFs with polydopamine coating for adaptable gasotransmitter generation and copper ion delivery on cardiovascular stents

Redox homeostasis disruptors enhanced cuproptosis effect for synergistic photothermal/chemodynamic therapy

The combination of chemodynamic therapy (CDT) with photothermal therapy (PTT) is a promising approach to enhance antitumor efficacy of chemotherapeutics. In this paper, we developed novel copper-chelated polydopamine (PDA) nanoparticles (NPs) functionalized with hyaluronic acid (HA) (Cu-PDA-HA NPs) to induce apoptosis and cuproptosis-induced cell death, synergistically combining PTT and CDT. Experimental results revealed that Cu-PDA-HA NPs can respond to excessive glutathione (GSH) and hydrogen peroxide (H2O2) in the tumor microenvironment (TME), which will enable their specific degradation, thereby leading to efficient accumulation of Cu2+ within tumor cells. The released Cu2+ ions were reduced by GSH to generate Cu+, which catalyzed in situ Fenton-like reactions to produce cytotoxic hydroxyl radicals (·OH), disrupting cellular redox homeostasis and promoting apoptosis-related CDT. Meanwhile, the photothermal effect of the Cu-PDA-HA NPs could enhance oxidative stress within the tumor by elevating the temperature and subsequent ·OH production. The enhanced oxidative stress made tumor cells more vulnerable to cuproptosis-induced toxicity. Furthermore, in vivo experiments demonstrated that Cu-PDA-HA NPs can still undergo a temperature increase of 18.9°C following 808 nm near-infrared irradiation (1.0 W/cm2, 5 min). Meanwhile, Cu-PDA-HA NPs were able to induce oligomerization of dihydrolipoamide S-acetyltransferase (DLAT) and down-regulate Fe-S cluster proteins such as ferredoxin (FDX1), thereby activating cuproptosis. Therefore, this study provides a novel approach for designing multifunctional nanoparticles with on-demand Cu2+ release and offers a fresh perspective for exploring synergistic therapeutic strategies involving CDT/PTT/apoptosis/cuproptosis.

Biofunctional coatings and drug-coated stents for restenosis therapy

Palliative therapy utilizing interventional stents, such as vascular stents, biliary stents, esophageal stents, and other stents, has been a prevalent clinical strategy for treating duct narrowing and partial blockage. However, stent restenosis after implantation usually significantly compromises therapeutic efficacy and patient safety. Clinically, vascular stent restenosis is primarily attributed to endothelial hyperplasia and coagulation, while the risk of biliary stent occlusion is heightened by bacterial adhesion and bile sludge accumulation. Similarly, granulation tissue hyperplasia leads to tracheal stent restenosis. To address these issues, surface modifications of stents are extensively adopted as effective strategies to reduce the probability of restenosis and extend their functional lifespan. Applying coatings is one of the technical routes involving a complex selection of materials, drug loading capacities, release rates, and other factors. This paper provides an extensive overview of state of the art drug-coated stents, addressing both challenges and future prospects in this domain. We aim to contribute positively to the ongoing development and potential clinical applications of drug-coated stents in interventional therapy.

Nanoparticle-based approaches for treating restenosis after vascular injury

Percutaneous coronary intervention (PCI) is currently the main method for treating coronary artery stenosis, but the incidence of restenosis after PCI is relatively high. Restenosis, the narrowing of blood vessels by more than 50% of the normal diameter after PCI, severely compromises the therapeutic efficacy. Therefore, preventing postinterventional restenosis is important. Vascular restenosis is mainly associated with endothelial injury, the inflammatory response, the proliferation and migration of vascular smooth muscle cells (VSMCs), excessive deposition of extracellular matrix (ECM) and intimal hyperplasia (IH) and is usually prevented by administering antiproliferative or anti-inflammatory drugs through drug-eluting stents (DESs); however, DESs can lead to uncontrolled drug release. In addition, as extracorporeal implants, they can cause inflammation and thrombosis, resulting in suboptimal treatment. Therefore, there is an urgent need for a drug carrier with controlled drug release and high biocompatibility for in vivo drug delivery to prevent restenosis. The development of nanotechnology has enabled the preparation of nanoparticle drug carriers with low toxicity, high drug loading, high biocompatibility, precise targeting, controlled drug release and excellent intracellular delivery ability. This review summarizes the advantages of nanoparticle drug carriers for treating vascular restenosis, as well as how nanoparticles have improved targeting, slowed the release of therapeutic agents, and prolonged circulation in vivo to prevent vascular restenosis more effectively. The overall purpose of this review is to present an overview of nanoparticle therapy for vascular restenosis. We expect these findings to provide insight into nanoparticle-based therapeutic approaches for vascular restenosis.

Endothelium-Mimicking Materials: A "Rising Star" for Antithrombosis

The advancement of antithrombotic materials has significantly mitigated the thrombosis issue in clinical applications involving various medical implants. Extensive research has been dedicated over the past few decades to developing blood-contacting materials with complete resistance to thrombosis. However, despite these advancements, the risk of thrombosis and other complications persists when these materials are implanted in the human body. Consequently, the modification and enhancement of antithrombotic materials remain pivotal in 21st-century hemocompatibility studies. Previous research indicates that the healthy endothelial cells (ECs) layer is uniquely compatible with blood. Inspired by bionics, scientists have initiated the development of materials that emulate the hemocompatible properties of ECs by replicating their diverse antithrombotic mechanisms. This review elucidates the antithrombotic mechanisms of ECs and examines the endothelium-mimicking materials developed through single, dual-functional and multifunctional strategies, focusing on nitric oxide release, fibrinolytic function, glycosaminoglycan modification, and surface topography modification. These materials have demonstrated outstanding antithrombotic performance. Finally, the review outlines potential future research directions in this dynamic field, aiming to advance the development of antithrombotic materials.

Application of metal-organic framework materials in regenerative medicine

In the past few decades, scaffolds manufactured from composite or hybrid biomaterials of natural or synthetic origin have made great strides in enhancing wound healing and repairing fractures and pathological bone loss. However, the prevailing use of such scaffolds in tissue engineering is accompanied by numerous constraints, including low mechanical stability, poor biological activity, and impaired cell proliferation and differentiation. The performance of scaffolds in wound and bone tissue engineering may be enhanced by some modifications in the synthesis of nanoscale metal-organic framework (nano-MOF) scaffolds. Nano-MOFs have attracted researchers' attention in recent years due to their distinctive features, which include tenability, biocompatibility, good mechanical stability, and ultrahigh surface area. The biological properties of scaffolds are enhanced and tissue regeneration is facilitated by the introduction of nano-MOFs. Moreover, the physicochemical characteristics, drug loading, and ion release capacities of the scaffolds are improved by the nanoscale structure and topological features of nano-MOFs, which also control stem cell differentiation, proliferation, and attachment. This review provides further comprehensive detail about the most recent uses of nano-MOFs in tissue engineering. The distinct characteristics of nano-MOFs are explored in enhancing tissue repair, wound healing, osteoinduction, and bone conductivity. Significant attributes include high antibacterial activity, substantial drug-loading capacity, and the ability to regulate drug release. Finally, this discussion addresses the obstacles, clinical impediments, and considerations encountered in the application of these nanomaterials to diverse scaffolds, tissue-mimicking structures, dressings, fillers, and implants for bone tissue repair and wound healing.

Infection Microenvironment-Responsive Coating on Titanium Surfaces for On-Demand Release of Therapeutic Gas and Antibiotic

Aseptic loosening and bacterial infection pose significant challenges in the clinical application of titanium (Ti) orthopedic implants, which are primarily caused by insufficient osseointegration and bacterial contamination. To address these issues, a responsive coating on Ti surface is constructed, which achieves enhanced osseointegration and infection elimination by on-demand release of therapeutic gas hydrogen sulfide (H2S) and antibiotic. TiO2 nanotubes (TNT) are anodized on the Ti surface to enhance its bioactivity and serve as reservoirs for the antibiotic. An infection microenvironment-responsive macromolecular H2S donor layer is coated on top of TNT to inhibit premature leakage of antibiotic. This layer exhibits a sustained release of low-dosage H2S, which is capable of promoting the osteogenic differentiation and migration of cells. Moreover, the compactness of the macromolecular H2S donor layer could be broken by bacterial invasion, leading to rapid antibiotic release thus preventing infection. In vitro antibacterial experiments validates significant antibacterial activity of the coating against both Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). Crucially, this coating effectively suppresses implant-associated infection with 98.7% antibacterial efficiency in a rat femoral bone defect model, mitigates inflammation at the defect site and promotes osseointegration of the Ti orthopedic implant.

Bioactive Metal-Organic Frameworks as a Distinctive Platform to Diagnosis and Treat Vascular Diseases

Vascular diseases (VDs) pose the leading threat worldwide due to high morbidity and mortality. The detection of VDs is commonly dependent on individual signs, which limits the accuracy and timeliness of therapies, especially for asymptomatic patients in clinical management. Therefore, more effective early diagnosis and lesion-targeted treatments remain a pressing clinical need. Metal-organic frameworks (MOFs) are porous crystalline materials formed by the coordination of inorganic metal ions and organic ligands. Due to their unique high specific surface area, structural flexibility, and functional versatility, MOFs are recognized as highly promising candidates for diagnostic and therapeutic applications in the field of VDs. In this review, the potential of MOFs to act as biosensors, contrast agents, artificial nanozymes, and multifunctional therapeutic agents in the diagnosis and treatment of VDs from the clinical perspective, highlighting the integration between clinical methods with MOFs is generalized. At the same time, multidisciplinary cooperation from chemistry, physics, biology, and medicine to promote the substantial commercial transformation of MOFs in tackling VDs is called for.

An anti-infection and biodegradable TFRD-loaded porous scaffold promotes bone regeneration in segmental bone defects: experimental studies

BACKGROUND

Addressing segmental bone defects remains a complex task in orthopedics, and recent advancements have led to the development of novel drugs to enhance the bone regeneration. However, long-term oral administration can lead to malnutrition and poor patient compliance. Scaffolds loaded with medication are extensively employed to facilitate the restoration of bone defects.

METHODS

Inspired by the local application of total flavonoids of Rhizoma Drynariae (TFRD) in the treatment of fracture, a novel 3D-printed HA/CMCS/PDA/TFRD scaffold with anti-infection, biodegradable and induced angiogenesis was designed, and to explore its preclinical value in segmental bone defect of tibia.

RESULTS

The scaffold exhibited good degradation and drug release performance. In vitro, the scaffold extract promoted osteogenesis by enhancing bone-related gene/protein expression and mineral deposition in BMSCs. It also stimulated endothelial cell migration and promoted angiogenesis through the upregulation of specific genes and proteins associated with cell migration and tube formation. This may be attributed to the activation of the PI3k/AKT/HIF-1α pathway, facilitating the processes of osteogenesis and angiogenesis. Furthermore, the HA/CMCS/PDA/TFRD scaffold was demonstrated to alleviate infection, enhance angiogenesis, promote bone regeneration, and increase the maximum failure force of new formed bone in a rat model of segmental bone defects.

CONCLUSION

Porous scaffolds loaded with TFRD can reduce infection, be biodegradable, and induce angiogenesis, presenting a novel approach for addressing tibial segmental bone defects.

Nitric Oxide Releasing Nanomaterials for Cardiovascular Applications

A central paradigm of cardiovascular homeostasis is that impaired nitric oxide (NO) bioavailability results in a wide array of cardiovascular dysfunction including incompetent endothelium-dependent vasodilatation, thrombosis, vascular inflammation, and proliferation of the intima. Over the course of more than a century, NO donating formulations such as organic nitrates and nitrites have remained a cornerstone of treatment for patients with cardiovascular diseases. These donors primarily produce NO in the circulation and are not targeted to specific (sub)cellular sites of action. However, safe, and therapeutic levels of NO require delivery of the right amount to a precise location at the right time. To achieve these aims, several recent strategies aimed at therapeutically generating or releasing NO in living systems have shown that polymeric and inorganic (silica, gold) nanoparticles and nanoscale metal-organic frameworks could either generate NO endogenously by the catalytic decomposition of endogenous NO substrates or can store and release therapeutically relevant amounts of NO gas. NO-releasing nanomaterials have been developed for vascular implants (such as stents and grafts) to target atherosclerosis, hypertension, myocardial ischemia-reperfusion injury, and cardiac tissue engineering. In this review, we discuss the advances in design and development of novel NO-releasing nanomaterials for cardiovascular therapeutics and critically examine the therapeutic potential of these nanoplatforms to modulate cellular metabolism, to regulate vascular tone, inhibit platelet aggregation, and limit proliferation of vascular smooth muscle with minimal toxic effects.

Inhibition effect of copper-bearing metals on arterial neointimal hyperplasia via the AKT/Nrf2/ARE pathway in vitro and in vivo

In-stent restenosis can be caused by the activation, proliferation and migration of vascular smooth muscle cells (VSMCs), which affects long-term efficacy of interventional therapy. Copper (Cu) has been proved to accelerate the endothelialization and reduce thrombosis formation, but little is known about its inhibition effect on the excessive proliferation of VSMCs. In this study, 316L-Cu stainless steel and L605-Cu cobalt-based alloy with varying Cu content were fabricated and their effects on surface property, blood compatibility and VSMCs were studied in vitro and in vivo. CCK-8 assay and EdU assay indicated that the Cu-bearing metals had obvious inhibitory effect on proliferation of VSMCs. Blood clotting and hemolysis tests showed that the Cu-bearing metals had good blood compatibility. The inhibition effect of the Cu-bearing metals on migration of cells was detected by Transwell assay. Further studies showed that Cu-bearing metals significantly decreased the mRNA expressions of bFGF, PDGF-B, HGF, Nrf2, GCLC, GCLM, NQO1 and HO1. The phosphorylation of AKT and Nrf2 protein expressions in VSMCs were significantly decreased by Cu-bearing metals. Furthermore, it was also found that SC79 and TBHQ treatments could recover the protein expressions of phospho-AKT and Nrf2, and their downstream proteins as well. Moreover, 316L-Cu stent proved its inhibitory action on the proliferation of VSMCs in vivo. In sum, the results demonstrated that the Cu-bearing metals possessed apparent inhibitory effect on proliferation and migration of VSMCs via regulating the AKT/Nrf2/ARE pathway, showing the Cu-bearing metals as promising stent materials for long-term efficacy of implantation.

Preparation of biocompatibility coating on magnesium alloy surface by sodium alginate and carboxymethyl chitosan hydrogel

Magnesium alloy is an excellent material for biodegradable cerebrovascular stents. However, the rapid degradation rate of magnesium alloy will make stent unstable. To improve the biocompatibility of magnesium alloy, in this study, biodegradable sodium alginate and carboxymethyl chitosan (SA/CMCS) was used to coat onto hydrothermally treated the surface of magnesium alloy by a dipping coating method. The results show that the SA/CMCS coating facilitates the growth, proliferation, and migration of endothelial cells and promotes neovascularization. Moreover, the SA/CMCS coating suppresses macrophage activation while promoting their transformation into M2 type macrophages. Overall, the SA/CMCS coating demonstrates positive effects on the safety and biocompatibility of magnesium alloy after implantation, and provide a promising therapy for the treatment of intracranial atherosclerotic stenosis in the future.

Passivation protein-adhesion platform promoting stent reendothelialization using two-electron-assisted oxidation of polyphenols

Superhydrophilic surfaces play an important role in nature. Inspired by this, scientists have designed various superhydrophilic materials that are widely used in the field of biomaterials, such as PEG molecular brushes and zwitterionic materials. However, superhydrophilic coatings with only anti-fouling properties do not satisfy the requirements for rapid reendothelialization of cardiovascular stent surfaces. Herein, a novel polyphenol superhydrophilic surface with passivated protein-adsorption properties was developed using two-electron oxidation of dopamine and polyphenols. This coating has a multiscale effects: 1) macroscopically: anti-fouling properties of superhydrophilic; 2) microscopically: protein adhesion properties of active groups (quinone-, amino-, hydroxyphenyl groups and aromatic ring). Polyphenols not only enhance the ability of coating to passivate protein-adsorption, but also make the coating have polyphenol-related biological functions. Therefore, the polyphenol and passivated protein-adsorption platform together maintain the stability of the scaffold microenvironment. This, in turn, provides favorable conditions for the growth of endothelial cells on the scaffold surface. In vivo implantation of the coated stents into the abdominal aorta resulted in uniform and dense endothelial cells covering the surface of the neointima. Moreover, new endothelial cells secreted large amounts of functional endothelial nitric oxide synthase like healthy endothelial cells. These results indicate that the polyphenol superhydrophilic coating potentially resists intra-stent restenosis and promotes surface reendothelialization. Hence, polyphenol superhydrophilic coatings with passivated protein-adsorption properties constructed by two-electron-assisted oxidation are a highly effective and versatile surface-modification strategy for implantable cardiovascular devices.

Fabrication of a Nanoscale Magnesium/Copper Metal-Organic Framework on Zn-Based Guided Bone Generation Membranes for Enhancing Osteogenesis, Angiogenesis, and Bacteriostasis Properties

Recently, zinc (Zn) and its alloys have demonstrated great potential as guided bone regeneration (GBR) membranes to treat the problems of insufficient alveolar bone volume and long-term osseointegration instability during dental implantology. However, bone regeneration is a complex process consisting of osteogenesis, angiogenesis, and antibacterial function. For now, the in vivo osteogenic performance and antibacterial activity of pure Zn are inadequate, and thus fabricating a platform to endow Zn membranes with multifunctions may be essential to address these issues. In this study, various bimetallic magnesium/copper metal-organic framework (Mg/Cu-MOF) coatings were fabricated and immobilized on pure Zn. The results indicated that the degradation rate and water stability of Mg/Cu-MOF coatings could be regulated by controlling the feeding ratio of Cu2+. As the coating and Zn substrate degraded, an alkaline microenvironment enriched with Zn2+, Mg2+, and Cu2+ was generated. It significantly improved calcium phosphate deposition, differentiation of osteoblasts, and vascularization of endothelial cells in the extracts. Among them, Mg/Cu1 showed the best comprehensive performance. The superior antibacterial activity of Mg/Cu1 was demonstrated in vitro and in vivo, which indicated significantly enhanced bacteriostatic activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli as compared to that of the bare sample. Bimetallic Mg/Cu-MOF coating could properly coordinate the multifunction on a Zn membrane and could be a promising platform for promoting its bone regeneration, which could pave the way for Zn-based materials to be used as barrier membranes in oral clinical trials.

Application of metal-organic frameworks-based functional composite scaffolds in tissue engineering

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.

Metal-organic framework-based platforms for implantation applications: recent advances and challenges

The development of minimally invasive technology has promoted the widespread use of implant interventional materials, which play an important role in alleviating patients' pain during and after surgery. Metal-organic frameworks (MOFs) and their related hybrids formed by bridging ligands and metal nodes via covalent bonds represent one of the smart platforms in implant interventional fields due to their large surface area, adjustable compositions and structures, biodegradability, etc. Significant progresses in the implantation application of MOF-based materials have been achieved recently, but these studies are still in the initial stage. This review highlights the recent advances of MOFs and their related hybrids in orthopedic implantation, cardio-vascular implantation, neural tissue engineering, and biochemical sensing. Each correction between the structural features of MOFs and their corresponding implanted works is highlighted. Finally, the confronting challenges and future perspectives in the implant interventional field are discussed.

Oxidative stress in acute pulmonary embolism: emerging roles and therapeutic implications

Oxidative stress is an imbalance between the body's reactive oxygen species and antioxidant defense mechanisms. Oxidative stress is involved in the development of several cardiovascular diseases, such as pulmonary hypertension, atherosclerosis, and diabetes mellitus. A growing number of studies have suggested the potential role of oxidative stress in the pathogenesis of pulmonary embolism. Biomarkers of oxidative stress in pulmonary embolism have also been explored, such as matrix metalloproteinases, asymmetric dimethylarginine, and neutrophil/lymphocyte ratio. Here, we comprehensively summarize some oxidative stress mechanisms and biomarkers in the development of acute pulmonary embolism and summarize related treatments based on antioxidant stress to explore effective treatment strategies for acute pulmonary embolism.

Heparin-network-mediated long-lasting coatings on intravascular catheters for adaptive antithrombosis and antibacterial infection

Bacteria-associated infections and thrombosis, particularly catheter-related bloodstream infections and catheter-related thrombosis, are life-threatening complications. Herein, we utilize a concise assembly of heparin sodium with organosilicon quaternary ammonium surfactant to fabricate a multifunctional coating complex. In contrast to conventional one-time coatings, the complex attaches to medical devices with arbitrary shapes and compositions through a facile dipping process and further forms robust coatings to treat catheter-related bloodstream infections and thrombosis simultaneously. Through their robustness and adaptively dissociation, coatings not only exhibit good stability under extreme conditions but also significantly reduce thrombus adhesion by 60%, and shows broad-spectrum antibacterial activity ( > 97%) in vitro and in vivo. Furthermore, an ex vivo rabbit model verifies that the coated catheter has the potential to prevent catheter-related bacteremia during implantation. This substrate-independent and portable long-lasting multifunctional coating can be employed to meet the increasing clinical demands for combating catheter-related bloodstream infections and thrombosis.

Recent advances and prospects of metal-organic frameworks in cancer therapies

Metal-organic frameworks (MOFs) have been broadly applied in biomedical and other fields. MOFs have high porosity, a large comparative area, and good biostability and have attracted significant attention, especially in cancer therapies. This paper presents the latest applications of MOFs in chemodynamic therapy (CDT), sonodynamic therapy (SDT), photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy (IT), and combination therapy for breast cancer. A combination therapy is the combination of two different treatment modalities, such as CDT and PDT combination therapy, and is considered more effective than separate therapies. Herein, we have also discussed the advantages and disadvantages of combination therapy in the treatment of breast cancer. This paper aims to illustrate the potential of MOFs in new cancer therapeutic approaches, discuss their potential advantages, and provide some reflections on the latest research results.

Recent advances in surface-mounted metal-organic framework thin film coatings for biomaterials and medical applications: a review

Coatings of metal-organic frameworks (MOFs) have potential applications in surface modification for medical implants, tissue engineering, and drug delivery systems. Therefore, developing an applicable method for surface-mounted MOF engineering to fabricate protective coating for implant tissue engineering is a crucial issue. Besides, the coating process was desgined for drug infusion and effect opposing chemical and mechanical resistance. In the present review, we discuss the techniques of MOF coatings for medical application in both in vitro and in vivo in various systems such as in situ growth of MOFs, dip coating of MOFs, spin coating of MOFs, Layer-by-layer methods, spray coating of MOFs, gas phase deposition of MOFs, electrochemical deposition of MOFs. The current study investigates the modification in the implant surface to change the properties of the alloy surface by MOF to improve properties such as reduction of the biofilm adhesion, prevention of infection, improvement of drugs and ions rate release, and corrosion resistance. MOF coatings on the surface of alloys can be considered as an opportunity or a restriction. The presence of MOF coatings in the outer layer of alloys would significantly demonstrate the biological, chemical and mechanical effects. Additionally, the impact of MOF properties and specific interactions with the surface of alloys on the anti-microbial resistance, anti-corrosion, and self-healing of MOF coatings are reported. Thus, the importance of multifunctional methods to improve the adhesion of alloy surfaces, microbial and corrosion resistance and prospects are summarized.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Angiogenic and immunomodulation role of ions for initial stages of bone tissue regeneration

It is widely known that bone has intrinsic capacity to self-regenerate after injury. However, the physiological regeneration process can be impaired when there is an extensive damage. One of the main reasons is due to the inability to establish a new vascular network that ensures oxygen and nutrient diffusion, leading to a necrotic core and non-junction of bone. Initially, bone tissue engineering (BTE) emerged to use inert biomaterials to just fill bone defects, but it eventually evolved to mimic bone extracellular matrix and even stimulate bone physiological regeneration process. In this regard, the stimulation of osteogenesis has gained a lot of attention especially in the proper stimulation of angiogenesis, being critical to achieve a successful osteogenesis for bone regeneration. Besides, the immunomodulation of a pro-inflammatory environment towards an anti-inflammatory one upon scaffold implantation has been considered another key process for a proper tissue restoration. To stimulate these phases, growth factors and cytokines have been extensively used. Nonetheless, they present some drawbacks such as low stability and safety concerns. Alternatively, the use of inorganic ions has attracted higher attention due to their higher stability and therapeutic effects with low side effects. This review will first focus in giving fundamental aspects of initial bone regeneration phases, focusing mainly on inflammatory and angiogenic ones. Then, it will describe the role of different inorganic ions in modulating the immune response upon biomaterial implantation towards a restorative environment and their ability to stimulate angiogenic response for a proper scaffold vascularization and successful bone tissue restoration. STATEMENT OF SIGNIFICANCE: The impairment of bone tissue regeneration when there is excessive damage has led to different tissue engineered strategies to promote bone healing. Significant importance has been given in the immunomodulation towards an anti-inflammatory environment together with proper angiogenesis stimulation in order to achieve successful bone regeneration rather than stimulating only the osteogenic differentiation. Ions have been considered potential candidates to stimulate these events due to their high stability and therapeutic effects with low side effects compared to growth factors. However, up to now, no review has been published assembling all this information together, describing individual effects of ions on immunomodulation and angiogenic stimulation, as well as their multifunctionality or synergistic effects when combined together.

Inorganic/organic combination: Inorganic particles/polymer composites for tissue engineering applications

Biomaterials have ushered the field of tissue engineering and regeneration into a new era with the development of advanced composites. Among these, the composites of inorganic materials with organic polymers present unique structural and biochemical properties equivalent to naturally occurring hybrid systems such as bones, and thus are highly desired. The last decade has witnessed a steady increase in research on such systems with the focus being on mimicking the peculiar properties of inorganic/organic combination composites in nature. In this review, we discuss the recent progress on the use of inorganic particle/polymer composites for tissue engineering and regenerative medicine. We have elaborated the advantages of inorganic particle/polymer composites over their organic particle-based composite counterparts. As the inorganic particles play a crucial role in defining the features and regenerative capacity of such composites, the review puts a special emphasis on the various types of inorganic particles used in inorganic particle/polymer composites. The inorganic particles that are covered in this review are categorised into two broad types (1) solid (e.g., calcium phosphate, hydroxyapatite, etc.) and (2) porous particles (e.g., mesoporous silica, porous silicon etc.), which are elaborated in detail with recent examples. The review also covers other new types of inorganic material (e.g., 2D inorganic materials, clays, etc.) based polymer composites for tissue engineering applications. Lastly, we provide our expert analysis and opinion of the field focusing on the limitations of the currently used inorganic/organic combination composites and the immense potential of new generation of composites that are in development.

Recent Advances in Functional Nanomaterials for Catalytic Generation of Nitric Oxide: A Mini Review

As a gaseous second messenger, nitric oxide (NO) plays an important role in a series of signal pathways. Research on the NO regulation for various disease treatments has aroused wide concern. However, the lack of accurate, controllable, and persistent release of NO has significantly limited the application of NO therapy. Profiting from the booming development of advanced nanotechnology, a mass of nanomaterials with the properties of controllable release have been developed to seek new and effective NO nano-delivery approaches. Nano-delivery systems that generate NO through catalytic reactions exhibit unique superiority in terms of precise and persistent release of NO. Although certain achievements have been made in the catalytically active NO delivery nanomaterials, some basic but critical issues, such as the concept of design, are of low attention. Herein, an overview of the generation of NO through catalytic reactions and the design principles of related nanomaterials are summarized. Then, the nanomaterials that generate NO through catalytic reactions are classified. Finally, the bottlenecks and perspectives are also discussed in depth for the future development of catalytical NO generation nanomaterials.

Surface Modification of Oxygenator Fibers with a Catalytically Active Metal-Organic Framework to Generate Nitric Oxide: An Ex Vivo Pilot Study

Coating all portions of an extracorporeal membrane oxygenation (ECMO) circuit with materials exhibiting inherent, permanent antithrombotic properties is an essential step to prevent thrombus-induced complications. However, developing antithrombotic coatings for oxygenator fibers within membrane oxygenators of ECMO systems has proven challenging. We have used polydopamine (PDA) to coat oxygenator fibers and immobilize a Cu-based metal-organic framework (MOF) on the surface to act as a nitric oxide (NO) catalyst. Importantly, the PDA/MOF coating will produce NO indefinitely from endogenous S-nitrosothiols and it has not previously been applied to ECMO oxygenator fibers.

DDTC-Cu(I) based metal-organic framework (MOF) for targeted melanoma therapy by inducing SLC7A11/GPX4-mediated ferroptosis

Disulfiram (DSF), a drug for alcohol withdrawal, has attracted extensive scientific attention due to its potential to treat cancer. The metabolite of DSF, diethyl dithiocarbamate (DDTC), forms a Cu-DDTC complex in vivo with copper ions, which has been shown to be a proteasome inhibitor with high antitumor activity. However, the in vivo stability of Cu-DDTC complexes remains a challenge. In this study, the nanomedicine Cu-BTC@DDTC with high antitumor activity was prepared by using the nanoscale metal-organic framework (MOF) Cu-BTC as a carrier and loading diethyldithiocarbamate (DDTC) through coordination interaction. The results showed that Cu-BTC@DDTC had high drug loading and adequate stability, and exhibited DDTC-Cu(I) chemical valence characteristics and polycrystalline structure features. In vitro cytocompatibility investigation and animal xenograft tumor model evaluation demonstrated the anti-cancer potential of Cu-BTC@DDTC, especially the combination of Cu-BTC@DDTC with low-dose cisplatin showed significant antitumor effect and biosafety. This study provides a feasible protocol for developing antitumor drugs based on the drug repurposing strategy.

Nanozyme-Enabled Treatment of Cardio- and Cerebrovascular Diseases

Cardio- and cerebrovascular diseases are two major vascular-related diseases that lead to death worldwide. Reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of diseases. Excessive ROS induce cellular context damage and lead to tissue dysfunction. Nanozymes, as emerging enzyme mimics, offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of ROS-related cardio- and cerebrovascular diseases by directly scavenging excess ROS or regulating pathologically related molecules. This review first introduces nanozyme-enabled therapeutic mechanisms at the cellular level. Then, the therapies for several typical cardio- and cerebrovascular diseases with nanozymes are discussed, mainly including cardiovascular diseases, ischemia reperfusion injury, and neurological disorders. Finally, the challenges and outlooks for the application of nanozymes are also presented. This review will provide some instructive perspectives on nanozymes and promote the development of enzyme-mimicking strategies in cardio- and cerebrovascular disease therapy.

Silk fibroin/chitosan coating with tunable catalytic nitric oxide generation for surface functionalization of cardiovascular stents

Developing a functional coating for vascular stents with sustainable and tunable NO release remains challenging. In this work, we report a silk fibroin/chitosan-based biopolymer coating incorporating copper ions as a catalyst for NO generation and demonstrate its potential for the surface functionalization of cardiovascular stents. Based on the differences in silk fibroin and chitosan coordinating with copper ions, the loading, bonding, and release of copper ions could be precisely regulated over a wide range by controlling the ratio of silk fibroin and chitosan. This system shows good cytocompatibility for endothelial cells and tunable catalytic activity to decompose S-nitroso-N-acetyl-D-penicillamine (SNAP) for NO generation. Consequently, a functionalized coating with sustainable and tunable NO catalysis generation was developed on the metallic stent. Based on good biocompatibility, tunable NO release, and simple processing, the coating is expected to have great promise in the field of intervention therapy of cardiovascular disease.

Copper-Based Metal-Organic Framework Induces NO Generation for Synergistic Tumor Therapy and Antimetastasis Activity

The interaction between platelets and circulating tumor cells (CTCs) contributes to distal tumor metastasis by protecting CTCs from immunological assault and shear stress, which can be disrupted by nitric oxide (NO) through inhibiting platelet-mediated adhesion. To eradicate primitive tumors and inhibit CTC-based pulmonary metastasis, a novel biomimetic nanomedicine (mCuMNO) is designed by encapsulating Cu⁺ -responsive S-nitrosoglutathione as a NO donor into a copper-based metal-organic framework (CuM). This work discovers that mCuMNO can target tumor regions and deplete local glutathione (GSH) to reduce Cu²⁺ to Cu⁺ , followed by triggering NO release and hydroxyl radicals (·OH) production, thereby interrupting platelet/CTC interplay and contributing to chemodynamic therapy. Detailed studies demonstrate that mCuMNO exhibits high efficiency and safety in tumor therapy and antimetastasis activity, sheding new light on the development of CuM-based tumor synthetic therapy.

Combinational Growth Factor and Gas Delivery for Thrombosis Prevention

Cardiovascular stents enable the rapid re-endothelialization of endothelial cells (ECs), and the constant suppression of smooth muscle cell (SMC) proliferation has been proved to effectively prevent thrombosis. However, the development and application of such stents are still insufficient due the delayed re-endothelialization progress, as well as the poor durability of the SMC inhibition. In this paper, we developed a mussel-inspired coating with the ability for the dual delivery of both growth factor (e.g., platelet-derived growth factor, PDGF) and therapeutic gas (e.g., nitric oxide, NO) for thrombosis prevention. We firstly synthesized the mussel-inspired co-polymer (DMHM) of dopamine methacrylamide (DMA) and hydroxyethyl methacrylate (HEMA) and then coated the DMHM on 316L SS stents combined with CuII. Afterwards, we immobilized the PDGF on the DMHM-coated stent and found that the PDGF could be released in the first 3 days to enhance the recruitment, proliferation, and migration of human umbilical vein endothelial cells (HUVECs) to promote re-endothelialization. The CuII could be “sealed” in the DMHM coating, with extended durability (2 months), with the capacity for catalyzed NO generation for up to 2 months to suppress the proliferation of SMCs. Such a stent surface modification strategy could enhance the development of the cardiovascular stents for thrombosis prevention.

3D printed Ti-5Cu alloy accelerates osteogenic differentiation of MC3T3-E1 cells by stimulating the M2 phenotype polarization of macrophages

Ti-5Cu alloy has been proved to have excellent mechanical properties and cell compatibility and has certain antibacterial properties due to the addition of Cu. However, there are few studies on the effects of Ti-5Cu alloy on macrophage polarization and immune-related bone formation. In this study, we prepared Ti-5Cu alloy by three-dimensional printing technology and found that Ti-5Cu alloy presented a much smoother surface compared with Ti. In addition, the CCK-8 results indicated the Ti-5Cu alloy had no cytotoxicity to RAW264.7 cells by co-culture. The results of inductively coupled plasma mass spectrometry showed that the concentration of Cu²⁺ was 0.133 mg/L after 7 days of co-culture, and the CCK-8 results proved that Cu²⁺ had no cytotoxicity to RAW264.7 at this concentration. Then, we studied the effects of Ti-5Cu alloy on macrophage polarization; it was shown that the Ti-5Cu alloy is more prone to modulate the RAW264.7 polarization towards the M2 phenotype and the conditioned medium derived from Ti-5Cu alloy significantly promoted the proliferation and osteogenic differentiation of MC3T3-E1 cells. However, when the expression of Oncostatin M (OSM) gene of RAW264.7 was knocked down, the osteogenic differentiation of MC3T3-E1 cells was decreased. This suggests that the OSM secreted by RAW264.7 co-cultured with Ti-5Cu alloy could accelerate the osteogenic differentiation of MC3T3-E1 cells by acting on OSMR/gp130 receptors.

Copper-containing titanium alloys promote angiogenesis in irradiated bone through releasing copper ions and regulating immune microenvironment

Poor vascularization was demonstrated as a factor inhibiting bone regeneration in patients receiving radiotherapy. Various copper-containing materials have been reported to increase angiogenesis, therefore might improve bone formation. In this study, a Ti6Al4V-1.5Cu alloy was prepared using selective laser melting (SLM) technology. The immunomodulatory and pro-angiogenic effects of the Ti6Al4V-1.5Cu alloys were examined. In vitro, Ti6Al4V-1.5Cu stimulated vascular formation by restraining inflammatory factors and provoking angiogenic factors in non-irradiated and irradiated macrophages. In vivo, the angiogenic effects of the Ti6Al4V-1.5Cu alloy were confirmed using an irradiated rat femur defect model. Moreover, we found that the biological effects of the Ti6Al4V-1.5Cu alloy were partially due to the release of copper ions and associated with PI3K-Akt signaling pathway. In conclusion, this study indicated the potential of the Ti6Al4V-1.5Cu alloy to promote angiogenesis by releasing copper ions and inhibiting inflammation in normal and irradiated tissues.

An organic selenium and VEGF-conjugated bioinspired coating promotes vascular healing

The introduction of drug-eluting stents (DESs) have yield a significant reduction in the incidence of re-stenosis, however, challenges remain including incomplete healing of the endothelium, inflammatory response and thrombogenesis at the site of vascular wall injury. Here, we developed a novel stent with polyphenol-polyamine surface combining the biological functions of nitric oxide gas and VEGF, selectively promoting the proliferation and migration of endothelial cells while suppressing smooth muscle cells. Compared with bare PLLA stents and traditional DESs, the functionalized stents enhanced vascular healing through remarkable inhibiting intimal hyperplasia and occurrence of thrombosis, accelerating the in-situ endothelium repair. Moreover, it showed a down-regulation of injury vascular inflammation response and reduction of the vessel wall injury in New Zealand Rabbits after 1- and 3-month implantation.

Pharmacological prevention of intimal hyperplasia: A state-of-the-art review

Intimal hyperplasia (IH) occurs in a considerable number of cases of blood vessel reconstruction by stenting or balloon angioplasty, venous bypass grafting, and arteriovenous dialysis accesses. It is triggered by endothelial injury during the vascular intervention and leads to vessel restenosis with life-threatening consequences for patients. To date, the drugs used for IH prevention in clinics-paclitaxel and rapalog drugs-have been focusing primarily on the vascular smooth muscle cell (VSMC) proliferation pathway of IH development. Limitations, such as endothelial toxicity and inappropriate drug administration timing, have spurred the search for new and efficient pharmacological approaches to control IH. In this state-of-the-art review, we present the pathways of IH development, focusing on the key events and actors involved in IH. Subsequently, we discuss different drugs and drug combinations interfering with these pathways based on their effect on peripheral circulation IH models in animal studies, or on clinical reports. The reports were obtained through an extensive search of peer-reviewed publications in Pubmed, Embase, and Google Scholar, with search equations composed based on five concepts around IH and their various combinations. To improve vascular intervention outcomes, rethinking of conventional therapeutic approaches to IH prevention is needed. Exploring local application of drugs and drug combinations acting on different pathophysiological pathways of IH development has the potential to provide effective and safe restenosis prevention.

Step-wise CAG@PLys@PDA-Cu2+ modification on micropatterned nanofibers for programmed endothelial healing

Native-like endothelium regeneration is a prerequisite for material-guided small-diameter vascular regeneration. In this study, a novel strategy is proposed to achieve phase-adjusted endothelial healing by step-wise modification of parallel-microgroove-patterned (i.e., micropatterned) nanofibers with polydopamine-copper ion (PDA-Cu²⁺) complexes, polylysine (PLys) molecules, and Cys-Ala-Gly (CAG) peptides (CAG@PLys@PDA-Cu²⁺). Using electrospun poly(l-lactide-co-caprolactone) random nanofibers as the demonstrating biomaterial, step-wise modification of CAG@PLys@PDA-Cu²⁺ significantly enhanced substrate wettability and protein adsorption, exhibited an excellent antithrombotic surface and outstanding phase-adjusted capacity of endothelium regeneration involving cell adhesion, endothelial monolayer formation, and the regenerated endothelium maturation. Upon in vivo implantation for segmental replacement of rabbit carotid arteries, CAG@PLys@PDA-Cu²⁺ modified grafts (2 mm inner diameter) with micropatterns on inner surface effectively accelerated native-like endothelium regeneration within 1 week, with less platelet aggregates and inflammatory response compared to those on non-modified grafts. Prolonged observations at 6- and 12-weeks post-implantation demonstrated a positive vascular remodeling with almost fully covered endothelium and mature smooth muscle layer in the modified vascular grafts, accompanied with well-organized extracellular matrix. By contrast, non-modified vascular grafts induced a disorganized tissue formation with a high risk of thrombogenesis. In summary, step-wise modification of CAG@PLys@PDA-Cu²⁺ on micropatterned nanofibers can significantly promote endothelial healing without inflicting thrombosis, thus confirming a novel strategy for developing functional vascular grafts or other blood-contacting materials/devices.

Nitric Oxide-Releasing Platforms for Treating Cardiovascular Disease

Cardiovascular disease (CVD) is the first leading cause of death globally. Nitric oxide (NO) is an important signaling molecule that mediates diverse processes in the cardiovascular system, thereby providing a fundamental basis for NO-based therapy of CVD. At present, numerous prodrugs have been developed to release NO in vivo. However, the clinical application of these prodrugs still faces many problems, including the low payloads, burst release, and non-controlled delivery. To address these, various biomaterial-based platforms have been developed as the carriers to deliver NO to the targeted tissues in a controlled and sustained manner. This review aims to summarize recent developments of various therapeutic platforms, engineered to release NO for the treatment of CVD. In addition, two potential strategies to improve the effectiveness of existing NO therapy are also discussed, including the combination of NO-releasing platforms and either hydrogen sulfide-based therapy or stem cell therapy. Hopefully, some NO-releasing platforms may provide important therapeutic benefits for CVD.

Efficient Delivery of Curcumin by Alginate Oligosaccharide Coated Aminated Mesoporous Silica Nanoparticles and In Vitro Anticancer Activity against Colon Cancer Cells

We designed and synthesized aminated mesoporous silica (MSN-NH2), and functionally grafted alginate oligosaccharides (AOS) on its surface to get MSN-NH2-AOS nanoparticles as a delivery vehicle for the fat-soluble model drug curcumin (Cur). Dynamic light scattering, thermogravimetric analysis, and X-ray photoelectron spectroscopy were used to characterize the structure and performance of MSN-NH2-AOS. The nano-MSN-NH2-AOS preparation process was optimized, and the drug loading and encapsulation efficiencies of nano-MSN-NH2-AOS were investigated. The encapsulation efficiency of the MSN-NH2-Cur-AOS nanoparticles was up to 91.24 ± 1.23%. The pH-sensitive AOS coating made the total release rate of Cur only 28.9 ± 1.6% under neutral conditions and 67.5 ± 1% under acidic conditions. According to the results of in vitro anti-tumor studies conducted by MTT and cellular uptake assays, the MSN-NH2-Cur-AOS nanoparticles were more easily absorbed by colon cancer cells than free Cur, achieving a high tumor cell targeting efficiency. Moreover, when the concentration of Cur reached 50 μg/mL, MSN-NH2-Cur-AOS nanoparticles showed strong cytotoxicity against tumor cells, indicating that MSN-NH2-AOS might be a promising tool as a novel fat-soluble anticancer drug carrier.

A Polyphenol-Network-Mediated Coating Modulates Inflammation and Vascular Healing on Vascular Stents

Localized drug delivery from drug-eluting stents (DESs) to target sites provides therapeutic efficacy with minimal systemic toxicity. However, DESs failure may cause thrombosis, delay arterial healing, and impede re-endothelialization. Bivalirudin (BVLD) and nitric oxide (NO) promote arterial healing. Nevertheless, it is difficult to combine hydrophilic signal molecules with hydrophobic antiproliferative drugs while maintaining their bioactivity. Here, we fabricated a micro- to nanoscale network assembly consisting of copper ion and epigallocatechin gallate (EGCG) via π-π interactions, metal coordination, and oxidative polymerization. The network incorporated rapamycin and immobilized BVLD by the thiol-ene "click" reaction and provided sustained rapamycin and NO release. Unlike rapamycin-eluting stents, those coated with the EGCG-Cu-rapamycin-BVLD complex favored competitive endothelial cell (EC) growth over that of smooth muscle cells, exhibited long-term antithrombotic efficacy, and attenuated the negative impact of rapamycin on the EC. In vivo stent implantation demonstrated that the coating promoted endothelial regeneration and hindered restenosis. Therefore, the polyphenol-network-mediated surface chemistry can be an effective strategy for the engineering of multifunctional surfaces.

Bioactive NIR-II Light-Responsive Shape Memory Composite Based on Cuprorivaite Nanosheets for Endometrial Regeneration

Intrauterine adhesions (IUAs) caused by mechanical damage or infection increase the risk of infertility in women. Although numerous physical barriers such as balloon or hydrogel are developed for the prevention of IUAs, the therapeutic efficacy is barely satisfactory due to limited endometrial healing, which may lead to recurrence. Herein, a second near-infrared (NIR-II) light-responsive shape memory composite based on the combination of cuprorivaite (CaCuSi₄ O₁₀ ) nanosheets (CUP NSs) as photothermal conversion agents and polymer poly(d,l-lactide-co-trimethylene carbonate) (PT) as shape memory building blocks is developed. The as-prepared CUP/PT composite possesses excellent shape memory performance under NIR-II light, and the improved operational feasibility as an antiadhesion barrier for the treatment of IUAs. Moreover, the released ions (Cu, Si) can stimulate the endometrial regeneration due to the angiogenic bioactivity. This study provides a new strategy to prevent IUA and restore the injured endometrium relied on shape memory composite with enhanced tissues reconstruction ability.

Modulation of Macrophage Response by Copper and Magnesium Ions in Combination with Low Concentrations of Dexamethasone

Macrophages have been deemed crucial for correct tissue regeneration, which is a complex process with multiple overlapping phases, including inflammation. Previous studies have suggested that divalent ions are promising cues that can induce an anti-inflammatory response, since they are stable cues that can be released from biomaterials. However, their immunomodulatory potential is limited in a pro-inflammatory environment. Therefore, we investigated whether copper and magnesium ions combined with low concentrations of the anti-inflammatory drug, dexamethasone (dex), could have a synergistic effect in macrophage, with or without pro-inflammatory stimulus, in terms of morphology, metabolic activity and gene expression. Our results showed that the combination of copper and dex strongly decreased the expression of pro-inflammatory markers, while the combination with magnesium upregulated the expression of IL-10. Moreover, in the presence of a pro-inflammatory stimulus, the combination of copper and dex induced a strong TNF-α response, suggesting an impairment of the anti-inflammatory actions of dex. The combination of magnesium and dex in the presence of a pro-inflammatory stimulus did not promote any improvement in comparison to dex alone. The results obtained in this study could be relevant for tissue engineering applications and in the design of platforms with a dual release of divalent ions and small molecules.

Sulfur-Mediated Polycarbonate Polyurethane for Potential Application of Blood-Contacting Materials

In this study, a sulfur-mediated polycarbonate polyurethane (PCU-SS) is developed by mimicking the catalyzing ability of glutathione peroxidase (GPx) on nitric oxide (NO) in the human body. The PCU-SS is endowed with the capability to produce NO based on disulfide bonds, which could strongly improve the biocompatibility of the materials. The characterization results indicate that PCU-SS could not only decrease the adhesion of platelets but also enhance the capability of anti-thrombus. Moreover, it is shown that PCU-SS has a good compatibility with endothelial cells (ECs), while has a marked inhibition capacity of the proliferation of smooth muscle cells (SMCs) and macrophages (MA). Meanwhile, the result of animal implantation experiments further demonstrates the good abilities of PCU-SS on anti-inflammation, anti-thrombus, and anti-hyperplasia. Our results offer a novel strategy for the modification of blood-contacting materials based on disulfide bonds. It is expected that the PCU-SS could shed new light on biocompatibility improvement of cardiovascular stents.

Applying Principles of Regenerative Medicine to Vascular Stent Development

Stents are a widely-used device to treat a variety of cardiovascular diseases. The purpose of this review is to explore the application of regenerative medicine principles into current and future stent designs. This review will cover regeneration-relevant approaches emerging in the current research landscape of stent technology. Regenerative stent technologies include surface engineering of stents with cell secretomes, cell-capture coatings, mimics of endothelial products, surface topography, endothelial growth factors or cell-adhesive peptides, as well as design of bioresorable materials for temporary stent support. These technologies are comparatively analyzed in terms of their regenerative effects, therapeutic effects and challenges faced; their benefits and risks are weighed up for suggestions about future stent developments. This review highlights two unique regenerative features of stent technologies: selective regeneration, which is to selectively grow endothelial cells on a stent but inhibit the proliferation and migration of smooth muscle cells, and stent-assisted regeneration of ischemic tissue injury.

Superlow Dosage of Intrinsically Bioactive Zinc Metal-Organic Frameworks to Modulate Endothelial Cell Morphogenesis and Significantly Rescue Ischemic Disease

Despite long-term efforts for ischemia therapy, proangiogenic drugs hardly satisfy therapy/safety/cost/mass production multiple evaluations and meanwhile with a desire to minimize dosages, thereby clinical applications have been severely hampered. Recently, metal ion-based therapy has emerged as an effective strategy. Herein, intrinsically bioactive Zn metal-organic frameworks (MOFs) were explored by bridging the dual superiorities of proangiogenic Zn²⁺ and facile/cost-effective/scalable MOFs. Zn-MOFs could enhance the morphogenesis of vascular endothelial cells (ECs) via the PI3K/Akt/eNOS pathway. However, high dosage is inevitable and Zn-MOFs suffer from insolubility and low stability, which lead to the bioaccumulation of Zn-MOFs and seriously potential toxicity risks. To alleviate this, it is required to decrease the dosage, but this can be entrapped into the dosage/therapy/safety contradiction and disappointing therapy effect. To address these challenges, the bioavailability of Zn-MOFs is urgent to improve for the minimization of dosage and significant therapy/safety. The mitochondrial respiratory chain is Zn²⁺ active, which inspired us to codecorate EC-targeted and mitochondria-localizing-sequence peptides onto Zn-MOF surfaces. Interestingly, after codecoration, a 100-fold reduced dosage acquired equally powerful vascularization, and the superlow dosage significantly rescued ischemia (4.4 μg kg^-1, about one order of magnitude lower than the published minimal value). Additionally, no obvious muscle injury was found after treatment. Potential toxicity risks were alleviated, benefiting from the superlow dosage. This advanced drug simultaneously satisfied comprehensive evaluations and dosage minimization. This work utilizes engineering thought to rationally design "all-around" bioactive MOFs and is expected to be applied for ischemia treatment.

A surface-eroding poly(1,3-trimethylene carbonate) coating for magnesium based cardiovascular stents with stable drug release and improved corrosion resistance

Magnesium alloys with integration of degradability and good mechanical performance are desired for vascular stent application. Drug-eluting coatings may optimize the corrosion profiles of magnesium substrate and reduce the incidence of restenosis simultaneously. In this paper, poly (trimethylene carbonate) (PTMC) with different molecular weight (50,000 g/mol named as PTMC5 and 350,000 g/mol named as PTMC35) was applied as drug-eluting coatings on magnesium alloys. A conventional antiproliferative drug, paclitaxel (PTX), was incorporated in the PTMC coating. The adhesive strength, corrosion behavior, drug release and biocompatibility were investigated. Compared with the PLGA control group, PTMC coating was uniform and gradually degraded from surface to inside, which could provide long-term protection for the magnesium substrate. PTMC35 coated samples exhibited much slower corrosion rate 0.05 μA/cm2 in comparison with 0.11 μA/cm2 and 0.13 μA/cm2 for PLGA and PTMC5 coated counterparts. In addition, PTMC35 coating showed more stable and sustained drug release ability and effectively inhibited the proliferation of human umbilical vein vascular smooth muscle cells. Hemocompatibility test indicated that few platelets were adhered on PTMC5 and PTMC35 coatings. PTMC35 coating, exhibiting surface erosion behavior, stable drug release and good biocompatibility, could be a good candidate as a drug-eluting coating for magnesium-based stent.

Endothelialization strategy of implant materials surface: The newest research in recent 5 years

In recent years, more and more metal or non-metal materials have been used in the treatment of cardiovascular diseases, but the vascular complications after transplantation are still the main factors restricting the clinical application of most grafts, such as acute thrombosis and graft restenosis. Implant materials have been extensively designed and surface optimized by researchers, but it is still too difficult to avoid complications. Natural vascular endodermis has excellent function, anti-coagulant and anti-intimal hyperplasia, and it is also the key to maintaining the homeostasis of normal vascular microenvironment. Therefore, how to promote the adhesion of endothelial cells (ECs) on the surface of cardiovascular materials to achieve endothelialization of the surface is the key to overcoming the complications after implant materialization. At present, the surface endothelialization design of materials based on materials surface science, bioactive molecules, and biological function intervention and feedback has attracted much attention. In this review, we summarize the related research on the surface modification of materials by endothelialization in recent years, and analyze the advantages and challenges of current endothelialization design ideas, explain the relationship between materials, cells, and vascular remodeling in order to find a more ideal endothelialization surface modification strategy for future researchers to meet the requirements of clinical biocompatibility of cardiovascular materials.

Polydopamine nanoparticles attenuate retina ganglion cell degeneration and restore visual function after optic nerve injury

Background

Oxidative stress contributes to retina ganglion cells (RGCs) loss in variety of ocular diseases, including ocular trauma, ocular vein occlusion, and glaucoma. Scavenging the excessed reactive oxygen species (ROS) in retinal neurovascular unit could be beneficial to RGCs survival. In this study, a polydopamine (PDA)-based nanoplatform is developed to protect RGCs.

Results

The PDA nanoparticles efficiently eliminate multi-types of ROS, protect endothelia and neuronal cells from oxidative damage, and inhibit microglia activation in retinas. In an optic nerve crush (ONC) model, single intravitreal injection of PDA nanoparticles could significantly attenuate RGCs loss via eliminating ROS in retinas, reducing the inflammatory response and maintaining barrier function of retinal vascular endothelia. Comparative transcriptome analysis of the retina implied that PDA nanoparticles improve RGCs survival probably by altering the expression of genes involved in inflammation and ROS production. Importantly, as a versatile drug carrier, PDA nanoparticles could deliver brimonidine (a neuroprotection drug) to synergistically attenuate RGCs loss and promote axon regeneration, thus restore visual function.

Conclusions

The PDA nanoparticle-based therapeutic nanoplatform displayed excellent performance in ROS elimination, providing a promising probability for treating retinal degeneration diseases.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01199-3.

Effective removal of levofloxacin drug and Cr(VI) from water by a composed nanobiosorbent of vanadium pentoxide@chitosan@MOFs

Wastewaters is generally polluted with various inorganic and organic contaminants which require effective multipurpose purification technology. In this respect, a novel V₂O₅@Ch/Cu-TMA nanobiosorbent was constructed via encapsulation of nanoscale metal organic frameworks (Cu-TMA) into vanadium pentoxide-imbedded-chitosan matrix to comprehensively investigate its efficiency in removal of levofloxacin drug (LEVO) (e.g., organic pollutant) and chromium (VI) (e.g., inorganic pollutant) from water. Both LEVO drug and Cr(VI) adsorptions were correlated to pseudo-second order (R² = 1) and Langmuir isotherm (R² = 0.9924 for LEVO and R² = 0.9815 for Cr(VI)). Adsorption of Cr(VI) was confirmed to be spontaneous and endothermic reactions, while LEVO was found to proceed via spontaneous and exothermic reactions based on the thermodynamic parameters. The emerged V₂O₅@Ch/Cu-TMA is regarded as an excellent nanobiosorbent for removal of inorganic contaminant as Cr(VI) from all natural water samples (tap, sea and wastewater) with percentages range 92.43%-96.95% and organic contaminant as LEVO drug from tap and wastewater (91.99%-97.20%).

3D Printed Wesselsite Nanosheets Functionalized Scaffold Facilitates NIR-II Photothermal Therapy and Vascularized Bone Regeneration

Various bifunctional scaffolds have recently been developed to address the reconstruction of tumor-initiated bone defects. Such scaffolds are usually composed of a near-infrared (NIR) photothermal conversion agent and a conventional bone scaffold for photothermal therapy (PTT) and long-term bone regeneration. However, the reported photothermal conversion agents are mainly restricted to the first biological window (NIR-I) with intrinsic poor tissue penetration depth. Also, most of these agents are non-bioactive materials, which induced potential systemic side toxicity after implantation. Herein, a NIR-II photothermal conversion agent (Wesselsite [SrCuSi4 O10 ] nanosheets, SC NSs) with tremendous osteogenic and angiogenic bioactivity, is rationally integrated with polycaprolactone (PCL) via 3D printing. The as-designed 3D composite scaffolds not only trigger osteosarcoma ablation through NIR-II light generated extensive hyperthermia, but also promote in vitro cellular proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs), respectively, and the ultimate enhancement of vascularized bone regeneration in vivo owing to the controlled and sustained release of bioactive ions (Sr, Cu, and Si). The authors' study provides a new avenue to prepare multifunctional bone scaffolds based on therapeutic bioceramics for repairing tumor-induced bone defects.