Microfluidic Electrospray Niacin Metal-Organic Frameworks Encapsulated Microcapsules for Wound Healing

Preparation of Au-modified metal organic framework nanozyme with tunable catalytic activity used for diabetic wound healing

Nanozymes with tunable catalytic activity have attracted attention in the field of biomedicine. Bacterial infections are the main causes of delayed or chronic wound healing. Therefore, antibacterial nanoplatforms with tunable enzymatic activity are urgently required for diabetic wound healing. Here, we propose a strategy for constructing Au-cluster-modified Prussian blue (PB) nanospheres (PB-Au) as antibacterial nanoplatforms for diabetic wound healing. The obtained PB-Au exhibited tunable peroxidase (POD)-like activity and maintained both photostability and catalytic stability. These advantages enhanced the antibacterial ability of the PB-Au enzyme. The results show that the bacterial biofilm disruption rate of the PB-Au enzyme was approximately 86 %. The bacterial elimination rate exceeded 95 %. Western blot (WB) data indicated that the expression of vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (CD31) was upregulated by PB-Au by approximately 1.3- and 1.4-fold, respectively. The WB results also suggested that PB-Au could promote angiogenesis. Animal experiments showed that PB-Au rapidly increased the temperature at the wound site by up to 52.6 ℃, which was beneficial for sterilization. The wound healing rate was approximately 98 %. The results demonstrate that PB-Au nanozymes with tunable peroxidase (POD)-like activities have great potential to accelerate diabetic wound healing.

Exploring the potential of incorporating ZIF-67 into electrospun poly (vinyl alcohol)/chitosan nanofibrous mats for wound healing

The current research emphasis is on the development of wound dressings that can inhibit bacterial infections and facilitate the treatment of complex wound healing processes. In this study, nanofibrous mats of polyvinyl alcohol/chitosan/ZIF-67(PVA/Cs/ZIF-67) were prepared using an electrospinning technique, to investigate their antibacterial and regenerative properties in a rat model of full-thickness skin wounds. ZIF-67 nanoparticles, with an average size of approximately 373.5 nm and a high specific surface area of 1849 m2 g-1, were synthesized. The structural characteristics of the mats were analyzed using FTIR and FESEM. TEM and EDS analysis confirmed the presence of ZIF-67 crystals on the surface of the scaffolds. The PVA/Cs/ZIF-67 nanofibrous mat exhibits the requisite porosity, swelling ratio, WVTR, contact angle, and satisfactory mechanical properties in both dry and wet conditions. The cytotoxicity test demonstrated that the nanofibers containing ZIF-67 nanoparticles are biocompatible and capable of supporting cell adhesion. Moreover, the nanofibers exhibit notable antibacterial activity up to 90 %. Additionally, in animal studies, the PVA/Cs/ZIF-67 nanofibrous mat demonstrated superior efficacy in wound healing, accompanied by reduced inflammation and enhanced skin remodeling. This substantiates the considerable potential of the PVA/Cs/ZIF-67 nanofibrous mat as a wound dressing for full-thickness skin wound healing.

Recent advances in electrospray encapsulation of probiotics: influencing factors, natural polymers and emerging technologies

The probiotic food sector is rapidly growing due to increased consumer demand for nutritional supplements. However, ensuring probiotic viability within the harsh conditions of the gastrointestinal tract remains a major challenge. While probiotic encapsulation is a promising solution to enhance probiotic viability, most traditional encapsulation methods have significant limitations. This review underscores the significance of adopting novel encapsulation technologies, particularly electrospray (ES), which offers superior encapsulation efficiency and versatility. It begins with an introduction to the principles and classification of ES, analyzes factors influencing the properties of ES microcapsules, and reviews the use of natural polymers in ES-based encapsulation. Additionally, it discusses recent advancements in this field, focusing on improvements in ES equipment (e.g., coaxial ES and emulsion ES) and the integration of ES with other technologies (e.g., microfluidic ES and ES-fluidized bed coating). Finally, it highlights existing challenges and explores future prospects in this evolving field, offering valuable insights for advancing probiotic encapsulation technologies and enhancing public health outcomes.

Dual-network hydrogel capsules for controlled molecular transport via pH and temperature responsiveness

We have developed innovative core-shell hydrogel capsules with a dual-network shell structure designed for precise control of molecular transport in response to external stimuli such as pH and temperature. The capsules were fabricated using a combination of microfluidic electrospray techniques and water-in-water (w/w) core-shell droplets templating. The primary network of the shell, calcium alginate (Ca-Alg), with a pKa around 3.4, exhibits sensitivity to pH. The secondary network of the shell, poly(ethylene glycol) methyl ether methacrylate (PEGMA), undergoes a volume phase transition near 60 °C. These properties enable precise molecular transport control in/out of the capsules by modulating the surface charges through varying pH and modifying pore size through temperature changes. Moreover, the dual-network shell structure not only significantly enhances the mechanical strength of the capsules but also improves their stability under external stimulus, ensuring structural integrity during the transport of molecules. This research lays the groundwork for further investigations into the multimodal stimuli-responsive hydrogel systems to control molecular transport, important in applications such as sensors and reactors for chemical cascade reactions.

Hydrogel-Based Strategies for Liver Tissue Engineering

The liver's role in metabolism, detoxification, and immune regulation underscores the urgency of addressing liver diseases, which claim millions of lives annually. Due to donor shortages in liver transplantation, liver tissue engineering (LTE) offers a promising alternative. Hydrogels, with their biocompatibility and ability to mimic the liver's extracellular matrix (ECM), support cell survival and function in LTE. This review analyzes recent advances in hydrogel-based strategies for LTE, including decellularized liver tissue hydrogels, natural polymer-based hydrogels, and synthetic polymer-based hydrogels. These materials are ideal for in vitro cell culture and obtaining functional hepatocytes. Hydrogels' tunable properties facilitate creating artificial liver models, such as organoids, 3D bioprinting, and liver-on-a-chip technologies. These developments demonstrate hydrogels' versatility in advancing LTE's applications, including hepatotoxicity testing, liver tissue regeneration, and treating acute liver failure. This review highlights the transformative potential of hydrogels in LTE and their implications for future research and clinical practice.

Emerging nanomaterials for novel wound dressings: From metallic nanoparticles and MXene nanosheets to metal-organic frameworks

The growing need for developing reliable and efficient wound dressings has led to recent progress in designing novel materials and formulations for different kinds of wounds caused by traumas, burns, surgeries, and diabetes. In cases of extreme urgency, accelerating wound recovery is of high importance to prevent persistent infection and biofilm formation. The application of nanotechnology in this domain resulted in the creation of distinct nanoplatforms for highly advanced wound-healing therapeutic approaches. Recently developed nanomaterials have been used as antibacterial agents or drug carriers to control wound infection. In the present review, the authors aim to review the recently published research on the effects of incorporating emerging nanomaterials into novel wound dressings and investigate their distinct roles in the wound healing process. It was determined that the metallic nanoparticles (NPs) exhibit antimicrobial and regenerative properties, metal oxide NPs regulate inflammation and promote tissue regeneration, MXene NPs enhance cell adhesion and proliferation, while metal-organic frameworks (MOFs) offer controlled drug delivery capabilities. Further research is required to fully understand the mechanisms and optimize the applications of these NPs in wound healing.

Boundarics in Biomedicine

"Boundarics in Biomedicine" is a cutting-edge interdisciplinary discipline, which is of great significance for understanding the origin of life, the interaction between internal and external environments, and the mechanism of disease occurrence and evolution. Here, the definition of Boundarics in Biomedicine is first described, including its connotation, research object, research method, challenges, and future perspectives. "Boundarics in Biomedicine" is a cutting-edge interdisciplinary discipline involving multiple fields (e.g., bioscience, medicine, chemistry, materials science, and information science) dedicated to investigating and solving key scientific questions in the formation, identification, and evolution of living organism boundaries. Specifically, it encompasses 3 levels: (a) the boundary between the living organism and the external environment, (b) internal boundary within living organism, and (c) the boundary related to disease in living organism. The advancement of research in Boundarics in Biomedicine is of great scientific significance for understanding the origin of life, the interaction between internal and external environments, and the mechanism of disease occurrence and evolution, thus providing novel principles, technologies, and methods for early diagnosis and prevention of major diseases, personalized drug development, and prognosis assessment (Fig. 1).

Ionic Polymerization-Based Synthesis of Bioinspired Adhesive Hydrogel Microparticles with Tunable Morphologies from Microfluidics

Shape-anisotropic hydrogel microparticles have attracted considerable attention for drug-delivery applications. Particularly, nonspherical hydrogel microcarriers with enhanced adhesive and circulatory abilities have demonstrated value in gastrointestinal drug administration. Herein, inspired by the structures of natural suckers, we demonstrate an ionic polymerization-based production of calcium (Ca)-alginate microparticles with tunable shapes from Janus emulsion for the first time. Monodispersed Janus droplets composed of sodium alginate and nongelable segments were generated using a coflow droplet generator. The interfacial curvatures, sizes, and production frequencies of Janus droplets can be flexibly controlled by varying the flow conditions and surfactant concentrations in the multiphase system. Janus droplets were ionically solidified on a chip, and hydrogel beads of different shapes were obtained. The in vitro and in vivo adhesion abilities of the hydrogel beads to the mouse colon were investigated. The anisotropic beads showed prominent adhesive properties compared with the spherical particles owing to their sticky hydrogel components and unique shapes. Finally, a novel computational fluid dynamics and discrete element method (CFD-DEM) coupling simulation was used to evaluate particle migration and contact forces theoretically. This review presents a simple strategy to synthesize Ca-alginate particles with tunable structures that could be ideal materials for constructing gastrointestinal drug delivery systems.

Application of metal-organic frameworks in infectious wound healing

Metal-organic frameworks (MOFs) are metal-organic skeleton compounds composed of self-assembled metal ions or clusters and organic ligands. MOF materials often have porous structures, high specific surface areas, uniform and adjustable pores, high surface activity and easy modification and have a wide range of prospects for application. MOFs have been widely used. In recent years, with the continuous expansion of MOF materials, they have also achieved remarkable results in the field of antimicrobial agents. In this review, the structural composition and synthetic modification of MOF materials are introduced in detail, and the antimicrobial mechanisms and applications of these materials in the healing of infected wounds are described. Moreover, the opportunities and challenges encountered in the development of MOF materials are presented, and we expect that additional MOF materials with high biosafety and efficient antimicrobial capacity will be developed in the future.

Microalgae-loaded biocompatible alginate microspheres for tissue repair

Hydrogel-based microcarriers have demonstrated effectiveness in wound repair treatments. The current research focus is creating and optimizing active microcarriers containing natural ingredients capable of conforming to diverse wound shapes and depths. Here, microalgae (MA)-loaded living alginate hydrogel microspheres were successfully fabricated via microfluidic electrospray technology, to enhance the effectiveness of wound healing. The stable living alginate hydrogel microspheres loaded with photoautotrophic MA were formed by cross-linking alginate with calcium ions. The combination of MA-loaded living alginate microspheres ensures high biocompatibility and efficient oxygen release, providing strong support for wound healing. Concurrently, vascular endothelial growth factor (VEGF) has been successfully introduced into the microspheres, further enhancing the comprehensive effectiveness of wound treatment. Covering the rat's wound with these MA-VEGF-loaded alginate microspheres further substantiated their significant role in promoting collagen deposition and vascular generation during the wound closure processes. These results confirm the outstanding value of microalgae-loaded live alginate hydrogel microspheres in wound healing, paving the way for new prospects in future clinical treatment methods.

MXene/TPU Hybrid Fabrics Enable Smart Wound Management and Thermoresponsive Drug Delivery

Thermoresponsive wound dressings with real-time monitoring and on-demand drug delivery have gained significant attention recently. However, such smart systems with stable temperature adjustment and drug release control are still lacking. Here, a novel smart fabric is designed for wound management with thermoresponsive drug delivery and simultaneously temperature monitoring. The triple layers of the fabrics are composed of the drug-loaded thermoresponsive nanofiber film, the MXene-optimized joule heating film, and the FPCB control chip. The precise and stable temperature stimulation can be easily achieved by applying a low voltage (0-4 V) to the heating film, achieving the temperature control ranging from 25 to 130 °C. And the temperature of the wound region can be monitored and adjusted in real time, demonstrating an accurate and low-voltage joule heating capability. Based on that, the drug-loaded film achieved precise thermoresponsive drug release and obtained significant antibacterial effects in vitro. The in vivo experiments also proved the hybrid fabric system with a notable antibacterial effect and accelerated wound healing process (about 30% faster than the conventional gauze group).

Developing natural polymers for skin wound healing

Natural polymers are complex organic molecules that occur in the natural environment and have not been subjected to artificial synthesis. They are frequently encountered in various creatures, including mammals, plants, and microbes. The aforementioned polymers are commonly derived from renewable sources, possess a notable level of compatibility with living organisms, and have a limited adverse effect on the environment. As a result, they hold considerable significance in the development of sustainable and environmentally friendly goods. In recent times, there has been notable advancement in the investigation of the potential uses of natural polymers in the field of biomedicine, specifically in relation to natural biomaterials that exhibit antibacterial and antioxidant characteristics. This review provides a comprehensive overview of prevalent natural polymers utilized in the biomedical domain throughout the preceding two decades. In this paper, we present a comprehensive examination of the components and typical methods for the preparation of biomaterials based on natural polymers. Furthermore, we summarize the application of natural polymer materials in each stage of skin wound repair. Finally, we present key findings and insights into the limitations of current natural polymers and elucidate the prospects for their future development in this field.

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.

Copper incorporated biomaterial-based technologies for multifunctional wound repair

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

Controllable Adaptive Molybdate-Oligosaccharide Nanoparticles Regulate M2 Macrophage Mitochondrial Function and Promote Angiogenesis via PI3K/HIF-1α/VEGF Pathway to Accelerate Diabetic Wound Healing

The complex wound environment of diabetic wounds leads to poor treatment efficacy, and the inflammatory disorders and vascular injury are the primary causes of death in such patients. Herein, a sprayable, controllable adaptive, pH-responsive nanosystem of molybdate and oligosaccharide (CMO) is specially developed as an immunomodulatory and angiogenesis-promotion material for diabetic wound healing. CMO exhibited pH-responsive release of Mo2+ and oligosaccharide (COS), specifically in response to the alkalescent environment observed in diabetic wounds. CMO provide an anti-inflammatory environment by promoting M2 polarization through significantly stimulating macrophage mitochondrial function. Specifically, CMO with a certain concentration reduce reactive oxygen species (ROS) and tumor necrosis factor α (TNF-α) expression, and upregulated mitochondrial membrane potential (MMP), superoxide dismutase (SOD), and interleukin 10 (IL-10) expression in macrophages. Moreover, CMO facilitate angiogenesis via upregulating the PI3K/HIF-1α/VEGF pathway-a critical process for the formation of new blood vessels that supply nutrients and oxygen to the healing tissue. Remarkably, CMO promote cell viability and migration of endothelial cells, and enhance the expression of angiogenic genes. In vitro and in vivo studies suggest this simple but powerful nanosystem targeting mitochondrial function has the potential to become an effective treatment for diabetic wound healing.

Effect of Silicone Patch Containing Metal-organic Framework on Hypertrophic Scar Suppression

BACKGROUND/AIM

Hypertrophic scars (HS) are an abnormal cutaneous condition of wound healing characterized by excessive fibrosis and disrupted collagen deposition. This study assessed the potential of a silicone patch embedded with chemically stable zirconium-based metal-organic frameworks (MOF)-808 structures to mitigate HS formation using a rabbit ear model.

MATERIALS AND METHODS

A silicone patch was strategically engineered by incorporating Zr-MOF-808, a composite structure comprising metal ions and organic ligands. Structural integrity of the Zr-MOF-808 silicone patch was validated using scanning electron microscopy and X-ray diffraction analysis. The animals were divided into three groups: a control, no treatment group (Group 1), a silicone patch treatment group (Group 2), and a group treated with a 0.2% loaded Zr-MOF-808 silicone patch (Group 3). HS suppression effects were quantified using scar elevation index (SEI), dorsal skin thickness measurements, and myofibroblast protein expression.

RESULTS

Histopathological examination of post-treatment HS samples revealed substantial reductions in SEI (34.6%) and epidermal thickness (49.5%) in Group 3. Scar hyperplasia was significantly diminished by 53.5% (p<0.05), while collagen density declined by 15.7% in Group 3 compared to Group 1. Western blot analysis of protein markers, including TGF-β1, collagen-1, and α-SMA, exhibited diminished levels by 8.8%, 12%, and 21.3%, respectively, in Group 3, and substantially higher levels by 21.9%, 27%, and 39.9%, respectively, in Group 2. On the 35th day post-wound generation, Zr-MOF-808-treated models exhibited smoother, less conspicuous, and flatter scars.

CONCLUSION

Zr-MOF-808-loaded silicone patch reduced HS formation in rabbit ear models by inducing the proliferation and remodeling of the wound healing process.

Metal-Organic Frameworks and Their Composites for Chronic Wound Healing: From Bench to Bedside

Chronic wounds are characterized by delayed and dysregulated healing processes. As such, they have emerged as an increasingly significant threat. The associated morbidity and socioeconomic toll are clinically and financially challenging, necessitating novel approaches in the management of chronic wounds. Metal-organic frameworks (MOFs) are an innovative type of porous coordination polymers, with low toxicity and high eco-friendliness. Documented anti-bacterial effects and pro-angiogenic activity predestine these nanomaterials as promising systems for the treatment of chronic wounds. In this context, the therapeutic applicability and efficacy of MOFs remain to be elucidated. It is, therefore, reviewed the structural-functional properties of MOFs and their composite materials and discusses how their multifunctionality and customizability can be leveraged as a clinical therapy for chronic wounds.

A sustained-release microcarrier effectively prolongs and enhances the antibacterial activity of lysozyme

Bacterial infections have become a great threat to public health in recent years. A primary lysozyme is a natural antimicrobial protein; however, its widespread application is limited by its instability. Here, we present a poly (N-isopropylacrylamide) hydrogel inverse opal particle (PHIOP) as a microcarrier of lysozyme to prolong and enhance the efficiency against bacteria. This PHIOP-based lysozyme (PHIOP-Lys) formulation is temperature-responsive and exhibits long-term sustained release of lysozyme for up to 16 days. It shows a potent antibacterial effect toward both Escherichia coli and Staphylococcus aureus, which is even higher than that of free lysozyme in solution at the same concentration. PHIOPs-Lys were demonstrated to effectively inhibit bacterial infections and enhance wound healing in a full-thickness skin wound rat model. This study provides a novel pathway for prolonging the enzymatic activity and antibacterial effects of lysozyme.

Yunnan Baiyao-loaded multifunctional microneedle patches for rapid hemostasis and cutaneous wound healing

Microneedle patches have been extensively employed for wound healing, while the lack of rapid hemostasis efficiency and multiple tissue-repair properties restrict their values in hemorrhagic wound applications. Herein, we propose a Yunnan Baiyao-loaded multifunctional microneedle patch, namely (BY + EGF)@MN, with deep tissue penetration, hemostasis efficiency and regenerative properties for hemorrhagic wound healing. The (BY + EGF)@MNs are designed with a BY-loaded Bletilla striata polysaccharide (BSP) base for rapid hemostasis and epidermal growth factor (EGF)-loaded GelMA tips for subsequent wound healing. As the BSP base can be fastly dissolved and completely release BY in 6 min to promote platelet adhesion and activate coagulation system, while the EGF can achieve a controlled and sustained release behavior in 7 days with the gradual degradation of the GelMA tips, the (BY + EGF)@MNs exhibit strong pro-coagulability and satisfactory hemostatic effect in a rat hepatic hemorrhage wound model. Based on the multifunctional characteristics, we have verified that when applied in rat cutaneous wounds, the proposed MNs can accelerate the wound healing process by enhancing neovascularization, fibroblast density, and collagen deposition. Thus, we believe that such (BY + EGF)@MNs are promising candidates for rapid hemostasis and diverse wound healing applications.

Celastrol-encapsulated microspheres prepared by microfluidic electrospray for alleviating inflammatory pain

Inflammatory pain is induced by trauma, infection, chemical stimulation, etc. It causes severe physical and psychological agony to patients. Celastrol has powerful anti-inflammatory property and has achieved good results in various inflammation-related diseases. However, the low water solubility and multi-system toxicity limit its clinical application. Herein, we proposed alginate microspheres with core-shell structure which encapsulated celastrol by microfluidic electrospray to effectively overcome the shortcomings and improve the therapeutic effect. The microspheres had uniform size and good biocompatibility, and could release the loaded drugs in the gut. The behavioral tests showed that the celastrol-loaded microspheres effectively alleviated inflammatory pain, and the hematoxylin and eosin staining (HE staining), immunofluorescence and detection of inflammatory cytokines showed the anti-inflammatory effect. These results indicated that the microspheres could reduce dose and toxicity without affecting efficacy, and facilitate the application of celastrol in different clinical situations.

Structural and biological engineering of 3D hydrogels for wound healing

Chronic wounds have become one of the most important issues for healthcare systems and are a leading cause of death worldwide. Wound dressings are necessary to facilitate wound treatment. Engineering wound dressings may substantially reduce healing time, reduce the risk of recurrent infections, and reduce the disability and costs associated. In the path of engineering of an ideal wound dressing, hydrogels have played a leading role. Hydrogels are 3D hydrophilic polymeric structures that can provide a protective barrier, mimic the native extracellular matrix (ECM), and provide a humid environment. Due to their advantages, hydrogels (with different architectural, physical, mechanical, and biological properties) have been extensively explored as wound dressing platforms. Here we describe recent studies on hydrogels for wound healing applications with a strong focus on the interplay between the fabrication method used and the architectural, mechanical, and biological performance achieved. Moreover, we review different categories of additives which can enhance wound regeneration using 3D hydrogel dressings. Hydrogel engineering for wound healing applications promises the generation of smart solutions to solve this pressing problem, enabling key functionalities such as bacterial growth inhibition, enhanced re-epithelialization, vascularization, improved recovery of the tissue functionality, and overall, accelerated and effective wound healing.

Microfluidics: Insights into Intestinal Microorganisms

Microfluidics is a system involving the treatment or manipulation of microscale (10^-9 to 10^-18 L) fluids using microchannels (10 to 100 μm) contained on a microfluidic chip. Among the different methodologies used to study intestinal microorganisms, new methods based on microfluidic technology have been receiving increasing attention in recent years. The intestinal tracts of animals are populated by a vast array of microorganisms that have been established to play diverse functional roles beneficial to host physiology. This review is the first comprehensive coverage of the application of microfluidics technology in intestinal microbial research. In this review, we present a brief history of microfluidics technology and describe its applications in gut microbiome research, with a specific emphasis on the microfluidic technology-based intestine-on-a-chip, and also discuss the advantages and application prospects of microfluidic drug delivery systems in intestinal microbial research.

Microtubes with gradient decellularized porcine sciatic nerve matrix from microfluidics for sciatic nerve regeneration

Long-range peripheral nerve defect is a severe and worldwide disease. With the increasing development of tissue engineering, the excellent ability of nerve extracellular matrix (ECM) in peripheral nerve injury (PNI) has been widely studied and verified. Here, we present a novel microtube that contains gradient decellularized porcine sciatic nerve ECM hydrogel (pDScNM-gel) from microfluidics for sciatic nerve regeneration. The pDScNM is confirmed to enhance cell proliferation and migration, and improve the axon growth of primary dorsal root ganglions (DRGs) in a concentration-related manner. These behaviors were also achieved when cells were co-cultured in a gradient pDScNM microtube. The in vivo sciatic nerve regeneration and functional recovery were also demonstrated by assembling the gradient pDScNM microtubes with a medical silicon tube. These results indicated that the microtubes with gradient pDScNM could act as a promising alternative for repairing peripheral nerve defects and showed great potential in clinical use.

A Self-Pumping Dressing with Multiple Liquid Transport Channels for Wound Microclimate Management

A microclimate with ventilation and proper wettability near the wound is vital for wound healing. In the case of pressure or absorption of large amounts of wound exudate, maintaining air circulation around the wound is currently a challenge for wound dressings. In this study, a novel self-pumping dressing (FAED) with multiple liquid transport channels is designed by combining a 3D spacer fabric, sodium alginate aerogel, and electrospun membrane. This unique structural design allows FAED to unidirectionally rapidly remove excess biofluid from the wound and transfer it through a special liquid transport channel to a liquid storage layer with a high absorption ratio. Importantly, the air circulation layer of FAED composed of liquid transport channels and spacer yarns provides excellent air permeability in both the horizontal (12.3 L min^-1 ) and vertical (272.02 mm s^-1 ) directions. Additionally, a lower compression modulus (0.14 MPa) and higher compression strength (0.15 MPa) enable the novel dressing to adapt to body contours and provide good supporting performance, as compared to foam dressings. Combined with its high biocompatibility, this unique dressing has significant potential for wound treatment and intensive care.

A novel insulin delivery system by β cells encapsulated in microcapsules

Introduction: Diabetes is a growing epidemic worldwide and requires effective clinical therapies. In recent years, β-cell transplantation has emerged as a promising treatment for diabetes, and an encapsulation approach has been proposed to ameliorate this treatment. Methods: Microfluidic technology had been used to generate microcapsules using a porous sodium alginate shell and a core containing β cells. The microcapsules were transplanted into diabetic mice and the therapeutic effect was measured. Results: Porous hydrogel shell allows exchange of small molecules of nutrients while protecting beta cells from immune rejection, while the core ensures high activity of the encapsulated cells. The glucose control effect of the microcapsules were more durable and better than conventional methods. Discussion: We believe that this system, which is composed of biocompatible porous hydrogel shell and enables highly activity of encapsulated β cells, can enhance therapeutic efficacy and has promising clinical applications.

3D-Printed Janus Piezoelectric Patches for Sonodynamic Bacteria Elimination and Wound Healing

Management of infected wounds has raised worldwide concerns. Attempts in this field focus on the development of intelligent patches for improving the wound healing. Here, inspired by the cocktail treatment and combinational therapy stratagem, we present a novel Janus piezoelectric hydrogel patch via 3-dimensional printing for sonodynamic bacteria elimination and wound healing. The top layer of the printed patch was poly(ethylene glycol) diacrylate hydrogel with gold-nanoparticle-decorated tetragonal barium titanate encapsulation, which realizes the ultrasound-triggered release of reactive oxygen species without leaking nanomaterials. The bottom layer is fabricated with methacrylate gelatin and carries growth factors for the cell proliferation and tissue reconstruction. Based on these features, we have demonstrated in vivo that the Janus piezoelectric hydrogel patch can exert substantial infection elimination activity under the excitation of ultrasound, and its sustained release of growth factors can promote tissue regeneration during wound management. These results indicated that the proposed Janus piezoelectric hydrogel patch had practical significance in sonodynamic infection alleviation and programmable wound healing for treating different clinical diseases.

Microenvironment-Based Diabetic Foot Ulcer Nanomedicine

Diabetic foot ulcers (DFU), one of the most serious complications of diabetes, are essentially chronic, nonhealing wounds caused by diabetic neuropathy, vascular disease, and bacterial infection. Given its pathogenesis, the DFU microenvironment is rather complicated and characterized by hyperglycemia, ischemia, hypoxia, hyperinflammation, and persistent infection. However, the current clinical therapies for DFU are dissatisfactory, which drives researchers to turn attention to advanced nanotechnology to address DFU therapeutic bottlenecks. In the last decade, a large number of multifunctional nanosystems based on the microenvironment of DFU have been developed with positive effects in DFU therapy, forming a novel concept of "DFU nanomedicine". However, a systematic overview of DFU nanomedicine is still unavailable in the literature. This review summarizes the microenvironmental characteristics of DFU, presents the main progress of wound healing, and summaries the state-of-the-art therapeutic strategies for DFU. Furthermore, the main challenges and future perspectives in this field are discussed and prospected, aiming to fuel and foster the development of DFU nanomedicines successfully.

The Human Dermis as a Target of Nanoparticles for Treating Skin Conditions

Skin has a preventive role against any damage raised by harmful microorganisms and physical and chemical assaults from the external environment that could affect the body's internal organs. Dermis represents the main section of the skin, and its contribution to skin physiology is critical due to its diverse cellularity, vasculature, and release of molecular mediators involved in the extracellular matrix maintenance and modulation of the immune response. Skin structure and complexity limit the transport of substances, promoting the study of different types of nanoparticles that penetrate the skin layers under different mechanisms intended for skin illness treatments and dermo-cosmetic applications. In this work, we present a detailed morphological description of the dermis in terms of its structures and resident cells. Furthermore, we analyze the role of the dermis in regulating skin homeostasis and its alterations in pathophysiological conditions, highlighting its potential as a therapeutic target. Additionally, we describe the use of nanoparticles for skin illness treatments focused on dermis release and promote the use of metal-organic frameworks (MOFs) as an integrative strategy for skin treatments.

Bioceramic materials with ion-mediated multifunctionality for wound healing

Regeneration of both anatomic and functional integrity of the skin tissues after injury represents a huge challenge considering the sophisticated healing process and variability of specific wounds. In the past decades, numerous efforts have been made to construct bioceramic-based wound dressing materials with ion-mediated multifunctionality for facilitating the healing process. In this review, the state-of-the-art progress on bioceramic materials with ion-mediated bioactivity for wound healing is summarized. Followed by a brief discussion on the bioceramic materials with ion-mediated biological activities, the emerging bioceramic-based materials are highlighted for wound healing applications owing to their ion-mediated bioactivities, including anti-infection function, angiogenic activity, improved skin appendage regeneration, antitumor effect, and so on. Finally, concluding remarks and future perspectives of bioceramic-based wound dressing materials for clinical practice are briefly discussed.

Hierarchical Microparticles Delivering Oxaliplatin and NLG919 Nanoprodrugs for Local Chemo-immunotherapy

Chemo-immunotherapy shows promising antitumor therapeutic outcomes for many primary cancers. Research in this area has been focusing on developing an ideal formula that enables the potent efficacy of chemo-immunotherapy in combating various cancers with reduced systemic toxicity. Herein, we present novel hierarchical hydrogel microparticles (MDDP) delivering oxaliplatin and NLG919 nanoprodrugs for local chemo-immunotherapy with desired features. The oxaliplatin prodrug and NLG919 were efficiently loaded in the dual-drug polymeric nanoparticles (DDP NPs), which were further encapsulated into a MDDP by using microfluidic technology. When delivered to the tumor site, the DDP NPs will be sustainedly released from the MDDP and retained locally to reduce systemic toxicity. After being endocytosed by cancer cells, the cytotoxic oxaliplatin and NLG919 could be successfully triggered to release from DDP NPs in a chain-shattering manner, leading to the immunogenic cell death (ICD) of tumor cells and the suppression of intratumoral immunosuppressive Tregs, respectively. With the assistance of an immune modulator, the chemotherapeutics-induced ICD could trigger robust systemic antitumor immune responses, presenting superior synergistic antitumor efficacies. Thus, the hierarchical microparticles could substantially inhibit the growth of mouse subcutaneous colorectal tumors, breast tumors, and colorectal tumors with large initial sizes via synergized chemo-immunotherapy, showing great potential in the practical clinical application of oncotherapy.

Microfluidic electrospray generation of porous magnetic Janus reduced graphene oxide/carbon composite microspheres for versatile adsorption

HYPOTHESIS

Graphene-based microparticles materials are broadly utilized in all sorts of fields owing to their outstanding properties. Despite great progress, the present graphene microparticles still face challenges in the aspects of size uniformity, motion flexibility, and tailorable surface chemistry, which limit their application in some specific fields, such as versatile adsorption. Hence, the development of novel graphene microparticles with the aforementioned characteristics is urgently required.

EXPERIMENTS

We presented a simple microfluidic electrospray strategy to generate magnetic Janus reduced graphene oxide/carbon (rGO/C) composite microspheres with a variety of unique features. Specifically, the microfluidic electrospray method endowed the obtaiend microspheres with sufficient size uniformity as well as magnetic responsive motion ability. Additionally, magnetic-mediated surface assembly of phase transition lysozyme (PTL) nanofilm on the microspheres rendered the deposited area hydrophilic while non-deposited area hydrophobic.

FINDINGS

Such magnetic Janus rGO/C composite microspheres with regionalized wettability characteristics not only showed prominent performance in adsorbing organic liquids with high adsorption capacity and remarkable reusability but also displayed satisfying biocompatibility for the efficient uptake of bilirubin. More encouragingly, the microspheres could serve as adsorbents in a simulative hemoperfusion setup, which further demonstrated the clinical application potential of the magnetic Janus rGO/C microspheres. Thus, we anticipate that the obtained magnetic Janus rGO/C composite microspheres could show multifunctional properties toward water treatment and blood molecule cleaning.

Bio-inspired natural platelet hydrogels for wound healing

Wound healing has invariably been a fundamental health concern, demanding manpower and materials and causing financial burdens. In this research, inspired by the hemostatic function of platelets, we proposed a novel bionic hydrogel by covalent amidation crosslinking natural platelet and alginate for wound healing. With the natural functional groups, the platelet-derived hydrogel exhibited outstanding biocompatibility and blood compatibility. By changing the addition ratio of platelets to alginates, the mechanical properties of the achieved hydrogel were variable to cater to different wound environments. Furthermore, silver nanoparticles could be loaded into the void space of the hydrogel which endowed the composites with superior anti-infective properties. We have demonstrated that the bio-inspired platelet hydrogel could promote hemostasis of acute tissue damage, prevent bacterial proliferation, and promote angiogenesis, collagen deposition, and granulation tissue formation in wound healing. These features signify the potential values of the bio-inspired platelet hydrogel in clinical applications.

Bioinspired Vascular Stents with Microfluidic Electrospun Multilayer Coatings for Preventing In-Stent Restenosis

In-stent restenosis (ISR) is seriously affecting the long-term prognosis of vascular interventional therapy and leading to enormous medical burdens. Great efforts have been devoted to developing functional vascular stents with desired features and properties for effective ISR prevention. Here, a multifunctional bionic vascular stent with designed coatings prepared using microfluidic electrospinning technology is presented. Such stents are composed of biocompatible, drug-loaded methylacrylated gelatin-polyethylene glycol diacrylate (GelMA-PEGDA) and polycaprolactone composite nanofibers on 316L stainless steel stents by an easy-to-operate step-by-step spraying method. Benefitting from the addition of polydopamine during the fabrications, the drug-loaded composite nanofibers can adhere well to both the stent and the vascular wall. Furthermore, as the inner fibrous layer of the stent contacting the lumen is equipped with heparin-vascular endothelial growth factor (Hep-VEGF), it plays an anticoagulation role and promotes the growth of endothelial cells; while the outer layer contacts the vascular wall and releases rapamycin slowly, which can restrain smooth muscle proliferation. By implanting this into the rabbit carotid artery, the multi-functional bionic demonstrates that the vascular stent can achieve good anti-thrombosis and in-stent restenosis effects, which indicates its potential values in vascular intervention and other biomedical fields.

Responsive and self-healing structural color supramolecular hydrogel patch for diabetic wound treatment

The treatment of diabetic wounds remains a great challenge for medical community. Here, we present a novel structural color supramolecular hydrogel patch for diabetic wound treatment. This hydrogel patch was created by using N-acryloyl glycinamide (NAGA) and 1-vinyl-1,2,4-triazole (VTZ) mixed supramolecular hydrogel as the inverse opal scaffold, and temperature responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel loaded with vascular endothelial cell growth factor (VEGF) as a filler. Supramolecular hydrogel renders hydrogel patch with superior mechanical properties, in which NAGA and VTZ also provide self-healing and antibacterial properties, respectively. Besides, as the existence of PNIPAM, the hydrogel patch was endowed with thermal-responsiveness property, which could release actives in response to temperature stimulus. Given these excellent performances, we have demonstrated that the supramolecular hydrogel patch could significantly enhance the wound healing process in diabetes rats by downregulating the expression of inflammatory factors, promoting collagen deposition and angiogenesis. Attractively, due to responsive optical property of inverse opal scaffold, the hydrogel patch could display color-sensing behavior that was suitable for the wound monitoring and management as well as guidance of clinical treatment. These distinctive features indicate that the presented hydrogel patches have huge potential values in biomedical fields.

Tough Wet Adhesion of Hydrogen-Bond-Based Hydrogel with On-Demand Debonding and Efficient Hemostasis

Hydrogels have been widely used in wet tissues. However, the insufficient adhesion of hydrogels for wound hemostasis remains a grand challenge. Herein, a facile yet effective strategy is developed to fabricate tough wet adhesion of hydrogen-bond-based hydrogel (PAAcVI hydrogel) using copolymerization of acrylic acid and 1-vinylimidazole in dimethyl sulfoxide followed by solvent exchange with water. The PAAcVI hydrogel shows equally robust adhesion (>400 J m^-2) to both wet and dry tissues. Moreover, the PAAcVI hydrogel also exhibits strong long-term stable adhesion underwater and in various wet environments. Meanwhile, the adhesion of PAAcVI hydrogel can be adjusted through Zn²⁺-ion-mediated on-demand debonding, which makes it easy to peel off from the tissue reducing pain during dressing removal and avoiding secondary injury. The PAAcVI hydrogel displays efficient hemostasis in the mice-tail docking model and mice-liver bleeding model. This hydrogen-bond-based hydrogel shows tough wet adhesion, and its adhesion is controllable, demonstrating its promising application in moisture-resistant adhesives, medical adhesives, and hemostatic materials.

Multifunctional fish gelatin hydrogel inverse opal films for wound healing

Background

Wound healing has become a worldwide healthcare issue. Attempts in the area focus on developing patches with the capabilities of avoiding wound infection, promoting tissue remolding, and reporting treatment status that are of great value for wound treatment.

Results

In this paper, we present a novel inverse opal film (IOF) patch based on a photo-crosslinking fish gelatin hydrogel with the desired features for wound healing and dynamic monitoring. The film with vibrant structure colors was constructed by using the mixture of fish gelatin methacryloyl, chitosan, and polyacrylic acid (PAA) to replicate colloidal crystal templates. As the structures of these natural biomolecules are well-retained during the fabrication, the resultant IOF was with brilliant biocompatibility, low immunogenicity, antibacterial property, as well as with the functions of promoting tissue growth and wound healing. In addition, the IOF presented interconnected nanopores and high specific surface areas for vascular endothelial growth factor loading, which could further improve its angiogenesis capability. More attractively, as the pH-responsive PAA was incorporated, the IOF patch could report the wound healing status through its real-time structural colors or reflectance spectra.

Conclusions

These features implied the practical value of the multifunctional fish gelatin hydrogel IOFs in clinical wound management.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01564-w.

Dynamically Responsive Scaffolds from Microfluidic 3D Printing for Skin Flap Regeneration

Biological scaffolds hold promising perspectives for random skin flap regeneration, while the practical application is greatly limited by their insufficient vascularization ability and the lack of responsiveness during the dynamical healing process. Herein, a novel MXene-incorporated hollow fibrous (MX-HF) scaffold with dynamically responsive channels is presented for promoting vascularization and skin flap regeneration by using a microfluidic-assisted 3D printing strategy. Benefiting from the photothermal conversion capacity of the MXene nanosheets and temperature-responsive ability of poly(NIPAM) hydrogels in the MX-HF scaffolds, they display a near-infrared (NIR)-responsive shrinkage/swelling behavior, which facilitates the cell penetration into the scaffold channels from the surrounding environment. Moreover, by incorporating vascular endothelial growth factor (VEGF) into the hydrogel matrix for controllable delivery, the MX-HF scaffolds can achieve promoted proliferation, migration, and proangiogenic effects of endothelial cells under NIR irradiation. It is further demonstrated in vivo that the NIR-responsive VEGF@MX-HF scaffolds can effectively improve skin flap survival by promoting angiogenesis, decreasing inflammation, and attenuating apoptosis in skin flaps. Thus, it is believed that such responsive MX-HF scaffolds are promising candidates for clinical random skin flap regeneration as well as other diverse tissue engineering applications.

ECM-mimetic immunomodulatory hydrogel for methicillin-resistant Staphylococcus aureus-infected chronic skin wound healing

The treatment of difficult-to-heal wounds remains a substantial clinical challenge due to deteriorative tissue microenvironment including the loss of extracellular matrix (ECM), excessive inflammation, impaired angiogenesis, and bacterial infection. Inspired by the chemical components, fibrous structure, and biological function of natural ECM, antibacterial and tissue environment-responsive glycopeptide hybrid hydrogel was developed for chronic wound healing. The hydrogel can facilitate the cell proliferation and macrophage polarization to M2 phenotype, and show potent antibacterial efficacy against both Gram-negative and Gram-positive bacteria. Significantly, the glycopeptide hydrogel accelerated the reconstruction of methicillin-resistant Staphylococcus aureus (MRSA)-infected full-thickness diabetic and scalding skin by orchestrating a pro-regenerative response indicated by abundant M2-type macrophages, attenuated inflammation, and promoted angiogenesis. Collectively, ECM-mimetic and immunomodulatory glycopeptide hydrogel is a promising multifunctional dressing to reshape the damaged tissue environment without additional drugs, exogenous cytokines, or cells, providing an effective strategy for the repair and regeneration of chronic cutaneous wounds.

Remediation of cadmium contaminated soil by composite spent mushroom substrate organic amendment under high nitrogen level

Cadmium (Cd) contamination in soil poses a serious threat to ecological environment and crop quality, especially under high nitrogen level. Here, the efficiency of composite organic amendment (spent mushroom substrate and its biochar) on remediation of Cd contaminated soil under high nitrogen level has been studied through a 42 days' soil incubation experiment. The results showed: (i) the application of composite organic amendment minimized the repercussions of high nitrogen and significantly reduced the exchangeable Cd proportion by 28.3%-29.5%, especially for Ca(NO₃)₂ treatment; (ii) the application of composite organic amendment improved the physicochemical properties of soil, such as pH, CEC and organic matter content increased by 0.63-0.99 unit, 39.69%-45.00% and 7.77%-11.47%, and EC decreased by 16.21%-44.47% compared with non-amendment Cd-contaminated soil, respectively; (iii) the application of composite organic amendment significantly increased the soil enzyme activities and microbial biomass, among which urease activity was increased most by 12.06-16.42 mg·g^-1·d^-1, and the copy number of AOA was decreased by 30.6%- 92.0%, and the copy number of AOB was increased most by about 45 times. In brief, the composite organic amendment can alleviate the adverse effects of Cd and nitrogen on the soil, but its long-term efficacy needs to be verified in further field study.

Prebiotics and Postbiotics Synergistic Delivery Microcapsules from Microfluidics for Treating Colitis

Manipulation of gut microbiota by bacterial metabolites has shown protective effects against colitis; while the efficacy is strictly limited by the poor oral delivery efficiency and single drug usage. Here, a novel prebiotics and postbiotics synergistic delivery microcapsule composed of indole-3-propionic acid (IPA) postbiotic and three prebiotics including alginate sodium, resistant starch (RS), and chitosan via microfluidic electrospray for preventing and treating colitis are proposed. It is found that oral administration of IPA microcapsules (IPA@MC) to mice can exert significant protective effects to colitis, suggesting the therapeutic synergy between prebiotics and postbiotics. Furthermore, the mechanism of the IPA@MC is revealed in modulating the gut microbiota, that is by significantly increasing the overall richness and abundance of short-chain fatty acids (SCFA) producing bacteria such as Faecalibacterium and Roseburia. These results indicate that the prebiotics and postbiotics synergistic delivery microcapsules are ideal candidates for treating colitis.

Advances in hydrogel-based vascularized tissues for tissue repair and drug screening

The construction of biomimetic vasculatures within the artificial tissue models or organs is highly required for conveying nutrients, oxygen, and waste products, for improving the survival of engineered tissues in vitro. In recent times, the remarkable progress in utilizing hydrogels and understanding vascular biology have enabled the creation of three-dimensional (3D) tissues and organs composed of highly complex vascular systems. In this review, we give an emphasis on the utilization of hydrogels and their advantages in the vascularization of tissues. Initially, the significance of vascular elements and the regeneration mechanisms of vascularization, including angiogenesis and vasculogenesis, are briefly introduced. Further, we highlight the importance and advantages of hydrogels as artificial microenvironments in fabricating vascularized tissues or organs, in terms of tunable physical properties, high similarity in physiological environments, and alternative shaping mechanisms, among others. Furthermore, we discuss the utilization of such hydrogels-based vascularized tissues in various applications, including tissue regeneration, drug screening, and organ-on-chips. Finally, we put forward the key challenges, including multifunctionalities of hydrogels, selection of suitable cell phenotype, sophisticated engineering techniques, and clinical translation behind the development of the tissues with complex vasculatures towards their future development.

Tailoring biocompatibility of composite scaffolds of collagen/guar gum with metal-organic frameworks

Metal-organic frameworks (MOFs) are microporous materials with high potential for biomedical applications. They are useful as drug delivery systems, antibacterials, and biosensors. Recently, composite materials comprised of polymer matrixes and MOFs have gained relevance in the biomedical field due to their high potential as materials to accelerate wound healing. In this work, we studied the potential applications of composite hydrogels containing MgMOF74, CaMOF74, and Zn(Atz)(Py). The composite hydrogels are biodegradable, being completely degraded after 15 days by the action of collagenase and papain. The composites showed high biocompatibility reaching cell viabilities up to 165.3 ± 8.6% and 112.3 ± 12.8% for porcine fibroblasts and human monocytes, respectively. The composites did not show hemolytic character and they showed antibacterial activity against Escherichia coli reaching up to 84 ± 5% of inhibition compared with amoxicillin (20 ppm). Further, the immunological assays revealed that the composites produce a favorable cell signaling stimulating the secretion of the TGF-β and MCP-1 cytokines and maintaining the secretion of TNF-α in normal levels. Finally, the composites showed potential to be used as controlled drug delivery systems reaching a release efficiency of 30.5 ± 2.5% for ketorolac. Finally, results revealed that ColGG-Zn(Atz)(Py) was the best formulation evaluated.

Porous MOF Microneedle Array Patch with Photothermal Responsive Nitric Oxide Delivery for Wound Healing

Patches with the capacity of controllable delivering active molecules toward the wound bed to promote wound healing are expectant all along. Herein, a novel porous metal-organic framework (MOF) microneedle (MN) patch enabling photothermal-responsive nitric oxide (NO) delivery for promoting diabetic wound healing is presented. As the NO-loadable copper-benzene-1,3,5-tricarboxylate (HKUST-1) MOF is encapsulated with graphene oxide (GO), the resultant NO@HKUST-1@GO microparticles (NHGs) are imparted with the feature of near-infrared ray (NIR) photothermal response, which facilitate the controlled release of NO molecules. When these NHGs are embedded in a porous PEGDA-MN, the porous structure, larger specific surface area, and sufficient mechanical strength of the integrated MN could promote a more accurate and deeper delivery of NO molecules into the wound site. By applying the resultant NHG-MN to the wound of a type I diabetic rat model, the authors demonstrate that it is capable of accelerating vascularization, tissue regeneration, and collagen deposition, indicating its bright prospect applied in wound healing and other therapeutic scenarios.

Platelet Membrane-Coated Nanocarriers Targeting Plaques to Deliver Anti-CD47 Antibody for Atherosclerotic Therapy

Atherosclerosis, the principle cause of cardiovascular disease (CVD) worldwide, is mainly characterized by the pathological accumulation of diseased vascular cells and apoptotic cellular debris. Atherogenesis is associated with the upregulation of CD47, a key antiphagocytic molecule that is known to render malignant cells resistant to programmed cell removal, or "efferocytosis." Here, we have developed platelet membrane-coated mesoporous silicon nanoparticles (PMSN) as a drug delivery system to target atherosclerotic plaques with the delivery of an anti-CD47 antibody. Briefly, the cell membrane coat prolonged the circulation of the particles by evading the immune recognition and provided an affinity to plaques and atherosclerotic sites. The anti-CD47 antibody then normalized the clearance of diseased vascular tissue and further ameliorated atherosclerosis by blocking CD47. In an atherosclerosis model established in ApoE^-/- mice, PMSN encapsulating anti-CD47 antibody delivery significantly promoted the efferocytosis of necrotic cells in plaques. Clearing the necrotic cells greatly reduced the atherosclerotic plaque area and stabilized the plaques reducing the risk of plaque rupture and advanced thrombosis. Overall, this study demonstrated the therapeutic advantages of PMSN encapsulating anti-CD47 antibodies for atherosclerosis therapy, which holds considerable promise as a new targeted drug delivery platform for efficient therapy of atherosclerosis.

Ice-Inspired Lubricated Drug Delivery Particles from Microfluidic Electrospray for Osteoarthritis Treatment

Particle-based drug delivery systems have a demonstrated value in osteoarthritis treatment. Research in this area trends to developing functional particles to improve the therapeutic effects. Herein, inspired by the super lubricated surface of ice that consists of a contiguous and ultrathin layer of bound water, we developed a 2-methylacryloyloxyethyl phosphorylcholine (MPC) decorated methacrylate anhydride- hyaluronic acid (HAMA) drug delivery particle with satisfying strength and enhanced lubrication from microfluidic electrospray for osteoarthritis treatment. Benefiting from the precise control of microfluidic electrospray flows, the generated drug delivery particles are imparted with well-tailored sizes and good dispersion. As the generated HAMA particles were modified by MPC with the positively (N+(CH3)3) and negatively (PO4-) charged chemical groups, they were imparted with enhanced lubrication effect and reduced friction on the joint interface by forming a hydrated lubricating layer. We have demonstrated that the MPC-modified HAMA particles could be employed as microcarriers for loading diclofenac sodium (DS) to inhibit the inflammatory response, thus further enhancing the osteoarthritis therapeutic effect in vivo and in vitro. Thus, the proposed drug delivery particles with satisfactory biocompatibility and therapeutic effect are great potential for clinical applications.

Biomass Microcapsules with Stem Cell Encapsulation for Bone Repair

Bone defects caused by trauma, tumor, or osteoarthritis remain challenging due to the lack of effective treatments in clinic. Stem cell transplantation has emerged as an alternative approach for bone repair and attracted widespread attention owing to its excellent biological activities and therapy effect. The attempts to develop this therapeutic approach focus on the generation of effective cell delivery vehicles, since the shortcomings of direct injection of stem cells into target tissues. Here, we developed a novel core-shell microcapsule with a stem cell-laden core and a biomass shell by using all-aqueous phase microfluidic electrospray technology. The designed core-shell microcapsules showed a high cell viability during the culture procedure. In addition, the animal experiments exhibited that stem cell-laden core-shell microcapsules have good biocompatibility and therapeutic effect for bone defects. This study indicated that the core-shell biomass microcapsules generated by microfluidic electrospray have promising potential in tissue engineering and regenerative medicine.

Droplet-based microfluidics in biomedical applications

Droplet-based microfluidic systems have been employed to manipulate discrete fluid volumes with immiscible phases. Creating the fluid droplets at microscale has led to a paradigm shift in mixing, sorting, encapsulation, sensing, and designing high throughput devices for biomedical applications. Droplet microfluidics has opened many opportunities in microparticle synthesis, molecular detection, diagnostics, drug delivery, and cell biology. In the present review, we first introduce standard methods for droplet generation (i.e., passive and active methods) and discuss the latest examples of emulsification and particle synthesis approaches enabled by microfluidic platforms. Then, the applications of droplet-based microfluidics in different biomedical applications are detailed. Finally, a general overview of the latest trends along with the perspectives and future potentials in the field are provided.