Polydopamine Decorated Microneedles with Fe-MSC-Derived Nanovesicles Encapsulation for Wound Healing

Multifunctional composite soluble microneedle patch based on "one stone, three birds" strategy for promoting the healing of infectious wounds

The colonisation of microorganisms such as bacteria forms a biofilm barrier on the wound's surface, preventing or delaying the penetration of antibacterial drugs. At the same time, continuous bacterial infection can cause oxidative stress and an inflammatory response and hinder angiogenesis, resulting in difficult wound healing. Based on the "one stone, three birds" strategy, a multi-functional nanoparticle composite soluble microneedle was designed and developed to solve this dilemma better. Ginsenoside-liposomes(R-Lipo) were prepared by ginsenoside Rg3, which had the effect of promoting repair, instead of cholesterol, and loaded with berberine (Ber), the antibacterial component of Coptis, together with polydopamine (PDA), which had anti-inflammatory and antioxidant properties, into microneedles based on hyaluronic acid (PDA/R-Lipo@BerMN). PDA/R-Lipo@BerMN tip can penetrate and destroy the integrity of the biofilm, dissolve under the action of hyaluronidase in the skin, and gradually release the drug to achieve rapid antibacterial, anti-inflammatory, antioxidant, and proliferation. As expected, the PDA/R-Lipo@BerMN patch effectively cleared ROS during wound closure, further promoted M2 macrophage polarisation, eradicated bacterial infection, and regulated the immune microenvironment, promoting inflammation suppression, collagen deposition, angiogenesis, and tissue regeneration.

Research Progress of Hydrogel Microneedles in Wound Management

Microneedles are a novel drug delivery system that offers advantages such as safety, painlessness, minimally invasive administration, simplicity of use, and controllable drug delivery. As a type of polymer microneedle with a three-dimensional network structure, hydrogel microneedles (HMNs) possess excellent biocompatibility and biodegradability and encapsulate various therapeutic drugs while maintaining drug activity, thus attracting significant attention. Recently, they have been widely employed to promote wound healing and have demonstrated favorable therapeutic effects. Although there are reviews about HMNs, few of them focus on wound management. Herein, we present a comprehensive overview of the design and preparation methods of HMNs, with a particular emphasis on their application status in wound healing, including acute wound healing, infected wound healing, diabetic wound healing, and scarless wound healing. Finally, we examine the advantages and limitations of HMNs in wound management and provide suggestions for future research directions.

Biological macromolecule-based hydrogels with antibacterial and antioxidant activities for wound dressing: A review

Because of the complex symptoms resulting from metabolic dysfunction in the wound microenvironment during bacterial infections, along with the necessity to combat free radicals, achieving prompt and thorough wound healing remains a significant medical challenge that has yet to be fully addressed. Moreover, the misuse of common antibiotics has contributed to the emergence of drug-resistant bacteria, underscoring the need for enhancements in the practical and commonly utilized approach to wound treatment. In this context, hydrogel dressings based on biological macromolecules with antibacterial and antioxidant properties present a promising new avenue for skin wound treatment due to their multifunctional characteristics. Despite the considerable potential of this innovative approach to wound care, comprehensive research on these multifunctional dressings is still insufficient. Consequently, the development of advanced biological macromolecule-based hydrogels, such as chitosan, alginate, cellulose, hyaluronic acid, and others, has been the primary focus of this study. These materials have been enriched with various antibacterial and antioxidant agents to confer multifunctional attributes for wound healing purposes. This review article aims to offer a comprehensive overview of the latest progress in this field, providing a critical theoretical basis for future advancements in the utilization of these advanced biological macromolecule-based hydrogels for wound healing.

Stem Cell-Derived Nanovesicles Embedded in Dual-Layered Hydrogel for Programmed ROS Regulation and Comprehensive Tissue Regeneration in Burn Wound Healing

Burn wounds often bring high risks of delayed healing process and even death. Reactive oxygen species (ROS) play a crucial role in burn wound repair. However, the dynamic process in wound healing requires both the generation of ROS to inhibit bacteria and the subsequent reduction of ROS levels to initiate and promote tissue regeneration, which calls for a more intelligent ROS regulation dressing system. Hence, a dual-layered hydrogel (Dual-Gel) tailored to the process of burn wound repair is designed: the inner layer hydrogel (Gel 2) first responds to bacterial hyaluronidase (Hyal) to deliver aggregation-induced emission photosensitizer functionalized adipose-derived stem cell nanovesicles, which generate ROS upon light irradiation to eliminate bacteria; then the outer layer hydrogel (Gel 1) continuously starts a long-lasting consumption of excess ROS at the wound site to accelerate tissue regeneration. Simultaneously, the stem cell nanovesicles trapped in the burns wound also provide nutrients and mobilize neighboring tissues to thoroughly assist in inflammation regulation, cell proliferation, migration, and angiogenesis. In summary, this study develops an intelligent treatment approach on burn wounds by programmatically regulating ROS and facilitating comprehensive wound tissue repair.

Accelerated infected wound healing by probiotic-based living microneedles with long-acting antibacterial effect

Delays in infected wound healing are usually a result of bacterial infection and local inflammation, which imposes a significant and often underappreciated burden on patients and society. Current therapies for chronic wound infection generally suffer from limited drug permeability and frequent drug administration, owing to the existence of a wound biofilm that acts as a barrier restricting the entry of various antibacterial drugs. Here, we report the design of a biocompatible probiotic-based microneedle (MN) patch that can rapidly deliver beneficial bacteria to wound tissues with improved delivery efficiency. The probiotic is capable of continuously producing antimicrobial substances by metabolizing introduced glycerol, thereby facilitating infected wound healing through long-acting antibacterial and anti-inflammatory effects. Additionally, the beneficial bacteria can remain highly viable (>80 %) inside MNs for as long as 60 days at 4 °C. In a mouse model of Staphylococcus aureus-infected wounds, a single administration of the MN patch exhibited superior antimicrobial efficiency and wound healing performance in comparison with the control groups, indicating great potential for accelerating infected wound closure. Further development of live probiotic-based MN patches may enable patients to better manage chronically infected wounds.

Polydopamine-coated bioactive glass for immunomodulation and odontogenesis in pulpitis

Preserving vital pulp in cases of dental pulpitis is desired but remains challenging. Previous research has shown that bioactive glass (BG) possesses notable capabilities for odontogenic differentiation. However, the immunoregulatory potential of BG for inflamed pulp is still controversial, which is essential for preserving vital pulp in the context of pulpitis. This study introduces a novel approach utilizing polydopamine-coated BG (BG-PDA) which demonstrates the ability to alleviate inflammation and promote odontogenesis for vital pulp therapy. In vitro, BG-PDA has the potential to induce M2 polarization of macrophages, resulting in decreased intracellular reactive oxygen species levels, inhibition of pro-inflammatory factor, and enhancement of anti-inflammatory factor expression. Furthermore, BG-PDA can strengthen the mitochondrial function in macrophages and facilitate odontogenic differentiation of human dental pulp cells. In a rat model of pulpitis, BG-PDA exhibits the capacity to promote M2 polarization of macrophages, alleviate inflammation, and facilitate dentin bridge formation. This study highlights the notable immunomodulatory and odontogenesis-inducing properties of BG-PDA for treating dental pulpitis, as evidenced by both in vitro and in vivo experiments. These results imply that BG-PDA could serve as a promising biomaterial for vital pulp therapy.

Dual-Barb Microneedle with JAK/STAT Inhibitor-Loaded Nanovesicles Encapsulation for Tendinopathy

Tendon stem/progenitor cells (TSPCs) are crucial for tendon repair, regeneration, and homeostasis. Dysfunction of TSPCs, due to aberrant activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway, contributes to tendinopathy. Unfortunately, the effectiveness of conventional subcutaneous injection targeting at suppressing JAK/STAT signaling pathway is limited due to the passive diffusion of drugs away from the injury site. Herein, a novel poly-gamma-glutamic acid (γ-PGA) dual-barb microneedle (MN) path loaded with TSPCs-derived nanovesicles (NVs) containing JAK/STAT inhibitor WP1066 (MN-WP1066-NVs) for tendinopathy treatment is designed. The dual-barb design of the MN ensures firm adhesion to the skin, allowing for sustained and prolonged release of WP1066-NVs, facilitating enhanced TSPCs self-renewal, migration, and stemness in tendinopathy. In vitro and in vivo experiments demonstrate that the degradation of γ-PGA patch tips facilitates the gradual release of WP1066-NVs at the lesion site. This release alleviates inflammation, suppresses extracellular matrix degradation, and restores normal tendon histological structure by inhibiting the JAK/STAT pathway. These findings suggest that the multifunctional dual-barb MN patch offers a novel and effective therapeutic strategy for tendinopathy treatment.

Bone Marrow Mesenchymal Stem Cell-Derived Nanovesicles Containing H8 Improve Hepatic Glucose and Lipid Metabolism and Exert Ameliorative Effects in Type 2 Diabetes

Purpose

Nanovesicles (NVs) derived from bone mesenchymal stem cells (BMSCs) as drug delivery systems are considered an effective therapeutic strategy for diabetes. However, its mechanism of action remains unclear. Here, we evaluated the efficacy and molecular mechanism of BMSC-derived NVs carrying the curcumin analog H8 (H8-BMSCs-NVs) on hepatic glucose and lipid metabolism in type 2 diabetes (T2D).

Subjects and Methods

Mouse BMSCs were isolated by collagenase digestion and H8-BMSCs-NVs were prepared by microvesicle extrusion. The effects of H8-BMSCs-NVs on hepatic glucose and lipid metabolism were observed in a T2D mouse model and a HepG2 cell insulin resistance model. To evaluate changes in potential signaling pathways, the PI3K/AKT/AMPK signaling pathway and expression levels of G6P and PEPCK were assessed by Western blotting.

Results

H8-BMSCs-NVs effectively improved lipid accumulation in liver tissues and restored liver dysfunction in T2D mice. Meanwhile, H8-BMSCs-NVs effectively inhibited intracellular lipid accumulation in the insulin resistance models of HepG2 cells. Mechanistic studies showed that H8-BMSCs-NVs activated the PI3K/AKT/AMPK signaling pathway and decreased the expression levels of G6P and PEPCK.

Conclusion

These findings demonstrate that H8-BMSCs-NVs improved hepatic glucose and lipid metabolism in T2D mice by activating the PI3K/AKT/AMPK signaling pathway, which provides novel evidence suggesting the potential of H8-BMSCs-NVs in the clinically treatment of T2D patients.

From Bone Remodeling to Wound Healing: An miR-146a-5p-Loaded Nanocarrier Targets Endothelial Cells to Promote Angiogenesis

Wound healing is a complex challenge that demands urgent attention in the clinical realm. Efficient angiogenesis is a pivotal factor in promoting wound healing. microRNA-146a (miR-146a) inhibitor has angiogenic potential in the periodontal ligament. However, free microRNAs (miRNAs) are poorly delivered into cells due to their limited tissue specificity and low intracellular delivery efficiency. To address this hurdle, we developed a nanocarrier for targeted delivery of the miR-146a inhibitor into endothelial cells. It is composed of a polyethylenimine (PEI)-modified mesoporous silica nanoparticle (MSN) core and a pentapeptide (YIGSR) layer that recognizes endothelial cells. In vitro, we defined that the miR-146a inhibitor and adiponectin (ADP) can modulate angiogenesis and the remodeling of periodontal tissues by activating the ERK and Akt signaling pathways. Then, we confirm the specificity of YIGSR to endothelial cells, and importantly, the nanocarrier effectively delivers the miR-146a inhibitor into endothelial cells, promoting angiogenesis. In a C57 mouse skin wound model, the miR-146a inhibitor is successfully delivered into endothelial cells at the wound site using the nanocarrier, resulting in the formation of new blood vessels with strong CD31 expression. Additionally, no significant differences are found in the expression levels of inflammatory markers interleukin-6 and tumor necrosis factor-α. This outcome not only brings new strategies for angiogenesis but also exhibits broader implications for bone remodeling and wound healing. The breakthrough holds significance for future research and clinical interventions.

A TLR4-Targeting Bioactive Peptide Hydrogel to Regulate Immune-Microenvironment for Diabetic Wound Repair

Persistent inflammation and disrupted immunoregulation are critical factors in impeding diabetic wound healing. While immunoregulatory hydrogel dressings hold significant promise for clinical applications in diabetic wound healing, the current application often demands intricate interventions and high-cost treatments involving cytokines and cell therapies. The development of single component immunoregulatory hydrogels remains a complex challenge. To address this issue, an active peptide hydrogel with immunoregulatory properties targeting the TLR4/NF-kB pathway, aiming to promote rapid diabetic wound healing, is engineered. The hydrogel sequence comprises naphthalene derivative, phenylalanine, and glycine to modulate hydrophilic/hydrophobic characteristics. The amino group on arginine contributes to tissue adhesion and regulation of intermolecular forces, ultimately yielding stable gels. The results underscore the formation of the peptide hydrogel (NFA) via the physical crosslinking of self-assembled nanofibers in water, thereby affording both excellent injectability and tissue adhesion. Notably, NFA demonstrates significant potential in promoting wound healing in a mouse model with full-thickness wounds by regulating macrophage responses in the inflammatory microenvironment through the TLR4/NF-kB pathway.

Injectable and Near-Infrared Light-Controllable Fibrin Hydrogels with Antimicrobial and Immunomodulating Properties for Infected Wound Healing

The management of infected wounds poses a significant challenge due to the growing issue of antibiotic resistance, underscoring the urgent necessity to innovate and implement alternative therapeutic strategies. These strategies should be capable of eliminating bacterial infections in infected wounds while circumventing the induction of multi-drug resistance. In the current study, we developed an easily prepared and injectable fibrin gel (FG) loaded with nanoparticles (NPs) that exhibit antibacterial and immunomodulatory properties to facilitate the healing of infected wounds. Initially, a novel type of NP was generated through the electrostatic interaction between the photothermal agent, mPEG-modified polydopamine (MPDA), and the nitric oxide (NO) donor, S-nitrosocysteamine (SNO). This interaction resulted in the formation of NPs referred to as SNO-loaded MPDA (SMPDA). Subsequently, the SMPDA was encapsulated into the FG using a double-barreled syringe, thereby producing the SMPDA-loaded FG (SMPDA/G). Experimental results revealed that SMPDA/G could effectively eliminate bacterial infections and alter the immune microenvironment. This efficacy is attributed to the synergistic combination of NO therapy and photothermal therapy, along with the role of SMPDA in facilitating M2 macrophage polarization within the gel. Accordingly, these findings suggest that the SMPDA/G holds substantial promise for clinical application in infected wound healing.

Bioactive Metal Ion-Coordinated Dynamic Hydrogel with Antibacterial, Immunomodulatory, and Angiogenic Activities for Infected Wound Repair

The repair of infected wounds is a complex physiopathologic process. Current studies on infected wound treatment have predominantly focused on infection treatment, while the factors related to delayed healing caused by vascular damage and immune imbalance are commonly overlooked. In this study, an extracellular matrix (ECM)-like dynamic and multifunctional hyaluronic acid (HA) hydrogel with antimicrobial, immunomodulatory, and angiogenic capabilities was designed as wound dressing for the treatment of infected skin wounds. The dynamic network in the hydrogel dressing was based on reversible metal-ligand coordination formed between sulfhydryl groups and bioactive metal ions. In our design, antibacterial silver and immunomodulatory zinc ions were employed to coordinate with sulfhydrylated HA and a vasculogenic peptide. In addition to the desired bioactivities for infected wounds, the hydrogel could also exhibit self-healing and injectable abilities. Animal experiments with infected skin wound models indicated that the hydrogel dressings enabled minimally invasive injection and seamless skin wound covering and then facilitated wound healing by efficient bacterial killing, continuous inflammation inhibition, and improved blood vessel formation. In conclusion, the metal ion-coordinated hydrogels with wound-infection-desired bioactivities and ECM-like dynamic structures represent a class of tissue bionic wound dressings for the treatment of infected and chronic inflammation wounds.

Nanomaterials-incorporated polymeric microneedles for wound healing applications

There is a growing and urgent need for developing novel biomaterials and therapeutic approaches for efficient wound healing. Microneedles (MNs), which can penetrate necrotic tissues and biofilm barriers at the wound and deliver active ingredients to the deeper layers in a minimally invasive and painless manner, have stimulated the interests of many researchers in the wound-healing filed. Among various materials, polymeric MNs have received widespread attention due to their abundant material sources, simple and inexpensive manufacturing methods, excellent biocompatibility and adjustable mechanical strength. Meanwhile, due to the unique properties of nanomaterials, the incorporation of nanomaterials can further extend the application range of polymeric MNs to facilitate on-demand drug release and activate specific therapeutic effects in combination with other therapies. In this review, we firstly introduce the current status and challenges of wound healing, and then outline the advantages and classification of MNs. Next, we focus on the manufacturing methods of polymeric MNs and the different raw materials used for their production. Furthermore, we give a summary of polymeric MNs incorporated with several common nanomaterials for chronic wounds healing. Finally, we discuss the several challenges and future prospects of transdermal drug delivery systems using nanomaterials-based polymeric MNs in wound treatment application.

NIR triggered polydopamine coated cerium dioxide nanozyme for ameliorating acute lung injury via enhanced ROS scavenging

Acute lung injury (ALI) is a life threatening disease in critically ill patients, and characterized by excessive reactive oxygen species (ROS) and inflammatory factors levels in the lung. Multiple evidences suggest that nanozyme with diversified catalytic capabilities plays a vital role in this fatal lung injury. At present, we developed a novel class of polydopamine (PDA) coated cerium dioxide (CeO2) nanozyme (Ce@P) that acts as the potent ROS scavenger for scavenging intracellular ROS and suppressing inflammatory responses against ALI. Herein, we aimed to identify that Ce@P combining with NIR irradiation could further strengthen its ROS scavenging capacity. Specifically, NIR triggered Ce@P exhibited the most potent antioxidant and anti-inflammatory behaviors in lipopolysaccharide (LPS) induced macrophages through decreasing the intracellular ROS levels, down-regulating the levels of TNF-α, IL-1β and IL-6, up-regulating the level of antioxidant cytokine (SOD-2), inducing M2 directional polarization (CD206 up-regulation), and increasing the expression level of HSP70. Besides, we performed intravenous (IV) injection of Ce@P in LPS induced ALI rat model, and found that it significantly accumulated in the lung tissue for 6 h after injection. It was also observed that Ce@P + NIR presented the superior behaviors of decreasing lung inflammation, alleviating diffuse alveolar damage, as well as promoting lung tissue repair. All in all, it has developed the strategy of using Ce@P combining with NIR irradiation for the synergistic enhanced treatment of ALI, which can serve as a promising therapeutic strategy for the clinical treatment of ROS derived diseases as well.

A differential-targeting core-shell microneedle patch with coordinated and prolonged release of mangiferin and MSC-derived exosomes for scarless skin regeneration

Microneedles for skin regeneration are conventionally restricted by uncontrollable multi-drug release, limited types of drugs, and poor wound adhesion. Here, a novel core-shell microneedle patch is developed for scarless skin repair, where the shell is composed of hydrophilic gelatin methacryloyl (GelMA) loaded with mangiferin, an anti-inflammatory small molecule, and the core is composed of hydrophobic poly (lactide-co-propylene glycol-co-lactide) dimethacrylates (PGLADMA) loaded with bioactive macromolecule and human mesenchymal stromal cell (hMSC)-derived exosomes. This material choice provides several benefits: the GelMA shell provides a swelling interface for tissue interlocking and rapid release of mangiferin at an early wound healing stage for anti-inflammation, whereas the PGLADMA core offers long-term encapsulation and release of exosomes (30% release in 3 weeks), promoting sustained angiogenesis and anti-inflammation. Our results demonstrate that the core-shell microneedle possesses anti-inflammatory properties and can induce angiogenesis both in vitro in terms of macrophage polarization and tube formation of human umbilical vein endothelial cells (HUVECs), and in vivo in terms of anti-inflammation, re-epithelization, and vessel formation. Importantly, we also observe reduced scar formation in vivo. Altogether, the degradation dynamics of our hydrophilic/hydrophobic materials enable the design of a core-shell microneedle for differential and prolonged release, promoting scarless skin regeneration, with potential for other therapies of long-term exosome release.

Recent advances in reactive oxygen species scavenging nanomaterials for wound healing

Reactive oxygen species play a crucial role in cell signaling pathways during wound healing phases. Treatment strategies to balance the redox level in the deep wound tissue are emerging for wound management. In recent years, reactive oxygen species scavenging agents including natural antioxidants, reactive oxygen species (ROS) scavenging nanozymes, and antioxidant delivery systems have been widely employed to inhibit oxidative stress and promote skin regeneration. Here, the importance of reactive oxygen species in different wound healing phases is critically analyzed. Various cutting-edge bioactive ROS nanoscavengers and antioxidant delivery platforms are discussed. This review also highlights the future directions for wound therapies via reactive oxygen species scavenging. This comprehensive review offers a map of the research on ROS scavengers with redox balancing mechanisms of action in the wound healing process, which benefits development and clinical applications of next-generation ROS scavenging-based nanomaterials in skin regeneration.

Targeting Diverse Wounds and Scars: Recent Innovative Bio-design of Microneedle Patch for Comprehensive Management

Wounds and the subsequent formation of scars constitute a unified and complex phased process. Effective treatment is crucial; however, the diverse therapeutic approaches for different wounds and scars, as well as varying treatment needs at different stages, present significant challenges in selecting appropriate interventions. Microneedle patch (MNP), as a novel minimally invasive transdermal drug delivery system, has the potential for integrated and programmed treatment of various diseases and has shown promising applications in different types of wounds and scars. In this comprehensive review, the latest applications and biotechnological innovations of MNPs in these fields are thoroughly explored, summarizing their powerful abilities to accelerate healing, inhibit scar formation, and manage related symptoms. Moreover, potential applications in various scenarios are discussed. Additionally, the side effects, manufacturing processes, and material selection to explore the clinical translational potential are investigated. This groundwork can provide a theoretical basis and serve as a catalyst for future innovations in the pursuit of favorable therapeutic options for skin tissue regeneration.

Highly Active Frozen Nanovesicles Microneedles for Senile Wound Healing via Antibacteria, Immunotherapy, and Skin Regeneration

Senile wound healing risks a variety of health complications and makes both economic and psychological burdens on patients greatly. Poor activity of aged dermal fibroblasts (A-FBs) and local disordered immunoreaction in the deep dermis contribute to delayed wound healing. Therefore, the locally complex microenvironment in deep requires additional processing. Herein, a novel double-layer hyaluronic acid methacrylate (HAMA)/polyvinyl alcohol (PVA) microneedle patch (MNP) coated by young fibroblast-derived exosomes (Y-EXOs) (Y-EXOs@HAMA/PVA MNP) is presented for deep drug delivery, aged wound healing and immunoregulation. A spraying and freeze-drying method is applied for keeping the bioactivity of the nanovesicles. An ideal loading of Y-EXOs and enhanced strength for penetration have realized after circulation for times. The Y-EXOs@HAMA/PVA MNP shows an excellent influence on delayed wound healing of aged skin with active A-FBs, more deposition of collagen and less production of IL-17A compared with application of aged fibroblast-derived exosomes (A-EXOs). Moreover, the content microRNAs in Y-EXOs and A-EXOs are sequenced for further study. This study initiatively demonstrates that Y-EXOs have effective function on both anti-aging and anti-inflammation and Y-EXOs@HAMA/PVA MNP is expected as a novel strategy for deep drug delivery for promoting hard wound healing in aged skin in future clinical application.

Functional biomacromolecules-based microneedle patch for the treatment of diabetic wound

Diabetic wounds are a common complication of diabetes. The prolonged exposure to high glucose and oxidative stress in the wound environment increases the risk of bacterial infection and abnormal angiogenesis, leading to amputation. Microneedle patches have shown promise in promoting the healing of diabetic wounds through transdermal drug delivery. These patches target the four main aspects of diabetic wound treatment: hypoglycemia, antibacterial action, inflammatory regulation, and tissue regeneration. By overcoming the limitations of traditional administration methods, microneedle patches enable targeted therapy for deteriorated tissues. The design of these patches extends beyond the selection of needle tip material and biomacromolecule encapsulated drugs; it can also incorporate near-infrared rays to facilitate cascade reactions and treat diabetic wounds. In this review, we comprehensively summarize the advantages of microneedle patches compared to traditional treatment methods. We focus on the design and mechanism of these patches based on existing experimental articles in the field and discuss the potential for future research on microneedle patches.

Injectable plant-derived polysaccharide hydrogels with intrinsic antioxidant bioactivity accelerate wound healing by promoting epithelialization and angiogenesis

Skin wound healing is a complex and dynamic process involving hemostasis, inflammatory response, cell proliferation and migration, and angiogenesis. Currently used wound dressings remain unsatisfactory in the clinic due to the lack of adjustable mechanical property for injection operation and bioactivity for accelerating wound healing. In this work, an "all-sugar" hydrogel dressing is developed based on dynamic borate bonding network between the hydroxyl groups of okra polysaccharide (OP) and xyloglucan (XG). Benefiting from the reversible crosslinking network, the resulting composite XG/OP hydrogels exhibited good shear-thinning and fast self-healing properties, which is suitable to be injected at wound beds and filled into irregular injured site. Besides, the proposed XG/OP hydrogels showed efficient antioxidant capacity by scavenging DPPH activity of 73.9 %. In vivo experiments demonstrated that XG/OP hydrogels performed hemostasis and accelerated wound healing with reduced inflammation, enhanced collagen deposition and angiogenesis. This plant-derived dynamic hydrogel offers a facile and effective approach for wound management and has great potential for clinical translation in feature.

Sonochemical Synthesis of Natural Polyphenolic Nanoparticles for Modulating Oxidative Stress

Natural polyphenolic compounds play a vital role in nature and are widely utilized as building blocks in the fabrication of emerging functional nanomaterials. Although diverse fabrication methodologies are developed in recent years, the challenges of purification, uncontrollable reaction processes and additional additives persist. Herein, a modular and facile methodology is reported toward the fabrication of natural polyphenolic nanoparticles. By utilizing low frequency ultrasound (40 kHz), the assembly of various natural polyphenolic building blocks is successfully induced, allowing for precise control over the particle formation process. The resulting natural polyphenolic nanoparticles possessed excellent in vitro antioxidative abilities and in vivo therapeutic effects in typical oxidative stress models including wound healing and acute kidney injury. This study opens new avenues for the fabrication of functional materials from naturally occurring building blocks, offering promising prospects for future advancements in this field.

Biological scaffold as potential platforms for stem cells: Current development and applications in wound healing

Wound repair is a complex challenge for both clinical practitioners and researchers. Conventional approaches for wound repair have several limitations. Stem cell-based therapy has emerged as a novel strategy to address this issue, exhibiting significant potential for enhancing wound healing rates, improving wound quality, and promoting skin regeneration. However, the use of stem cells in skin regeneration presents several challenges. Recently, stem cells and biomaterials have been identified as crucial components of the wound-healing process. Combination therapy involving the development of biocompatible scaffolds, accompanying cells, multiple biological factors, and structures resembling the natural extracellular matrix (ECM) has gained considerable attention. Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells, providing them with an environment conducive to growth, similar to that of the ECM. These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing. This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing, emphasizing their capacity to facilitate stem cell adhesion, proliferation, differentiation, and paracrine functions. Additionally, we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

Gelatin Microspheres Based on H8-Loaded Macrophage Membrane Vesicles to Promote Wound Healing in Diabetic Mice

Diabetic wound healing remains a worldwide challenge for both clinicians and researchers. The high expression of matrix metalloproteinase 9 (MMP9) and a high inflammatory response are indicative of poor diabetic wound healing. H8, a curcumin analogue, is able to treat diabetes and is anti-inflammatory, and our pretest showed that it has the potential to treat diabetic wound healing. However, H8 is highly expressed in organs such as the liver and kidney, resulting in its unfocused use in diabetic wound targeting. (These data were not published, see Table S1 in the Supporting Information.) Accordingly, it is important to pursue effective carrier vehicles to facilitate the therapeutic uses of H8. The use of H8 delivered by macrophage membrane-derived nanovesicles provides a potential strategy for repairing diabetic wounds with improved drug efficacy and fast healing. In this study, we fabricated an injectable gelatin microsphere (GM) with sustained MMP9-responsive H8 macrophage membrane-derived nanovesicles (H8NVs) with a targeted release to promote angiogenesis that also reduces oxidative stress damage and inflammation, promoting diabetic wound healing. Gelatin microspheres loaded with H8NV (GMH8NV) stimulated by MMP9 can significantly facilitate the migration of NIH-3T3 cells and facilitate the development of tubular structures by HUVEC in vitro. In addition, our results demonstrated that GMH8NV stimulated by MMP9 protected cells from oxidative damage and polarized macrophages to the M2 phenotype, leading to an inflammation inhibition. By stimulating angiogenesis and collagen deposition, inhibiting inflammation, and reducing MMP9 expression, GMH8NV accelerated wound healing. This study showed that GMH8NVs were targeted to release H8NV after MMP9 stimulation, suggesting promising potential in achieving satisfactory healing in diabetic treatment.

Gynura divaricata (L.) DC. promotes diabetic wound healing by activating Nrf2 signaling in diabetic rats

THE ETHNOPHARMACOLOGICAL SIGNIFICANCE

Diabetic chronic foot ulcers pose a significant therapeutic challenge as a result of the oxidative stress caused by hyperglycemia. Which impairs angiogenesis and delays wound healing, potentially leading to amputation. Gynura divaricata (L.) DC. (GD), a traditional Chinese herbal medicine with hypoglycemic effects, has been proposed as a potential therapeutic agent for diabetic wound healing. However, the underlying mechanisms of its effects remain unclear.

AIM OF THE STUDY

In this study, we aimed to reveal the effect and potential mechanisms of GD on accelerating diabetic wound healing in vitro and in vivo.

MATERIALS AND METHODS

The effects of GD on cell proliferation, apoptosis, reactive oxygen species (ROS) production, migration, mitochondrial membrane potential (MMP), and potential molecular mechanisms were investigated in high glucose (HG) stimulated human umbilical vein endothelial cells (HUVECs) using CCK-8, flow cytometry assay, wound healing assay, immunofluorescence, DCFH-DA staining, JC-1 staining, and Western blot. Full-thickness skin defects were created in STZ-induced diabetic rats, and wound healing rate was tracked by photographing them every day. HE staining, immunohistochemistry, and Western blot were employed to investigate the effect and molecular mechanism of GD on wound healing in diabetic rats.

RESULTS

GD significantly improved HUVEC survival, decreased apoptosis, lowered ROS production, restored MMP, improved migration ability, and raised VEGF expression. The use of Nrf2-siRNA completely abrogated these effects. Topical application of GD promoted angiogenesis and granulation tissue growth, resulting in faster healing of diabetic wounds. The expression of VEGF, CD31, and VEGFR was elevated in the skin tissue of diabetic rats after GD treatment, which upregulated HO-1, NQO-1, and Bcl-2 expression while downregulating Bax expression via activation of the Nrf2 signaling pathway.

CONCLUSION

The findings of this study indicate that GD has the potential to serve as a viable alternative treatment for diabetic wounds. This potential arises from its ability to mitigate the negative effects of oxidative stress on angiogenesis, which is regulated by the Nrf2 signaling pathway. The results of our study offer valuable insights into the therapeutic efficacy of GD in the treatment of diabetic wounds, emphasizing the significance of directing interventions towards the Nrf2 signaling pathway to mitigate oxidative stress and facilitate the process of angiogenesis.

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

A microneedle patch realizes weight loss through photothermal induction of fat browning

As a globally prevalent disease, obesity leads to many chronic diseases, so it is important to develop safe and effective treatments with fewer side effects and lasting weight loss. In this study, we developed a biodegradable hyaluronic acid microneedle patch loaded with polydopamine nanoparticles and mirabegron, which directly acted on subcutaneous white adipose tissue, and then induced browning of white adipose tissue through mild photothermal therapy. The approach showed excellent browning-promoting ability and biocompatibility. It is noteworthy that the weight of untreated mice increased by 9%, while the weight of obese mice decreased by nearly 19% after photothermal treatment. In addition, when mirabegron was used in combination with photothermal therapy, the weight loss of obese mice was more significant, with a weight loss of about 22%. This microneedle patch exhibited attractive potential for body slimming.

MgO@polydopamine Nanoparticle-Loaded Photothermal Microneedle Patches Combined with Chitosan Gel Dressings for the Treatment of Infectious Wounds

As for wound drug delivery, microneedles (MNs) have attracted wide attention. However, while effective at increasing the depth of drug delivery, traditional MNs often have limited drug loads and have difficulty penetrating scabs on wounds. Herein, we develop a drug delivery system combining MgO@polydopamine (MgO@PDA) nanoparticle-loaded photothermal MN patches and chitosan (CS) gel to inhibit the formation of scabs and deliver sufficient drugs into deep tissue. When inserted into the wound, the MN system can keep the wound bed moist and weakly acidic to inhibit the formation of scabs and accelerate wound closure. The released MgO@PDA nanoparticles from both the tips and the backing layer, which immensely increase the drug load, continuously release Mg2+ in the moist, weakly acidic wound bed, promoting tissue migration and the formation of microvessels. MgO@PDA nanoparticles show excellent antibacterial activity under near-infrared irradiation synergized with the CS gel, and the PDA coating can also overcome the adverse effects of oxidative stress. Through in vitro and in vivo experiments, the MN system showed remarkable antibacterial, antioxidant, anti-inflammatory, and pro-angiogenic effects, indicating its potential in the treatment of infectious wounds.

Photothermal and Photocatalytic Glycol Chitosan and Polydopamine-Grafted Oxygen Vacancy Bismuth Oxyiodide (BiO1-x I) Nanoparticles for the Diagnosis and Targeted Therapy of Diabetic Wounds

Treatment of diabetic wounds is a significant clinical challenge due to the massive infections caused by bacteria. In this study, multifunctional glycol chitosan and polydopamine-coated BiO1-x I (GPBO) nanoparticles (NPs) with near-infrared (NIR) photothermal and photocatalytic abilities are prepared. When infection occurs, the local microenvironment becomes acidic, and the pH-switchable GPBO can target the bacteria of the wound site. The NIR-assisted GPBO treatment exhibits anti-bacterial effects with fast response, high efficiency, and long duration to Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. GPBO achieves excellent photothermal imaging and CT imaging of the mouse subcutaneous abscess model. With the assistance of NIR irradiation, the GPBO promotes the healing of the diabetic wound model with the effects of anti-bacteria, anti-inflammation, the M2 polarization promotion of macrophages, and angiogenesis. This is the first-time report of nano-sized BiO1-x I. The synthesis and selected application for the imaging and targeted therapy of diabetic wounds are presented. This study offers an example of the NP-assisted precise diagnosis and therapy of bacterial infection diseases.

Recent progress on the development of bioinspired surfaces with high aspect ratio microarray structures: From fabrication to applications

Surfaces with high aspect ratio microarray structures can implement sophisticated assignment in typical fields including microfluidics, sensor, biomedicine, et al. via regulating their deformation or the material properties. Inspired by natural materials and systems, for example sea cockroaches, water spiders, cacti, lotus leaves, rice leaves, and cedar leaves, many researchers have focused on microneedle functional surface studies. When the surface with high aspect ratio microarray structures is stimulated by the external fields, such as optical, electric, thermal, magnetic, the high aspect ratio microarray structures can undergo hydrophilic and hydrophobic switching or shape change, which may be gifted the surfaces with the ability to perform complex task, including directional liquid/air transport, targeted drug delivery, microfluidic chip sensing. In this review, the fabrication principles of various surfaces with high aspect ratio microarray structures are classified and summarized. Mechanisms of liquid manipulation on hydrophilic/hydrophobic surfaces with high aspect ratio microarray structures are clarified based on Wenzel model, Cassie model, Laplace pressure theories and so on. Then the intelligent control strategies have been demonstrated. The applications in microfluidic, drug delivery, patch sensors have been discussed. Finally, current challenges and new insights of future prospects for dynamic manipulation of liquid/air based on biomimetic surface with high aspect ratio microarray structures are also addressed.

Evaluation of Reactive Oxygen Species Scavenging of Polydopamine with Different Nanostructures

Reactive oxygen species (ROS) play an important role in cellular metabolism and many oxidative stress-related diseases, while excessive accumulation of ROS will lead to genetic changes in cells and promote the occurrence of inflammatory diseases or cell death. Nature-inspired polydopamine (PDA) with tailored nanostructures emerges as an ROS scavenger and is considered as an effective approach to inflammation-related diseases. However, the effects of nanoparticle structure on PDA scavenging efficacy and efficiency remain uncovered. In this work, three typical PDA nanoparticles including solid PDA, mesoporous PDA, and hollow PDA are synthesized, and of which physiochemical properties are characterized. Furthermore, their ROS scavenging performance is investigated by in vitro evaluation of radical removal. Among the three nanoparticles, mesoporous PDA is demonstrated to have the highest scavenging capability, mainly due to its specific surface area. Finally, the study on three in vivo inflammation models is constructed. The results confirm that mesoporous PDA is the most potent scavenger of ROS and more effective in reducing reperfusion injury, improving renal function, and preventing periodontitis progression, respectively. Together with the good biosafety and biocompatibility profiles, PDA nanoparticles, mesoporous PDA in particular, can be a promising avenue of ROS scavenging in fight against the inflammatory diseases.

Hierarchical double-layer microneedles accomplish multicenter skin regeneration in diabetic full-thickness wounds

INTRODUCTION

Managing large chronic wounds presents significant challenges because of inadequate donor sites, infection, and lack of structural support from dermal substitutes. Hydrogels are extensively used in various forms to promote chronic wound healing and provide a three-dimensional spatial structure, through growth factors or cell transport.

OBJECTIVES

We present a novel multicenter regenerative model that is capable of regenerating and merging simultaneously to form a complete layer of skin. This method significantly reduces wound healing time compared to the traditional centripetal healing model. We believe that our model can improve clinical outcomes and pave the way for further research into regenerative medicine.

METHODS

We prepared a novel multi-island double-layer microneedle (MDMN) using gelatin-methacryloylchitosan (GelMA-CS). The MDMN was loaded with keratinocytes (KCs) and dermal fibroblasts (FBs). Our aim in this study was to explore the therapeutic potential of MDMN in a total skin excision model.

RESULTS

The MDMN model replicated the layered structure of full-thickness skin and facilitated tissue regeneration and healing via dual omni-bearing. Multi-island regeneration centres accomplished horizontal multicentric regeneration, while epidermal and dermal cells migrated synchronously from each location. This produced a healing area approximately 4.7 times greater than that of the conventional scratch tests. The MDMN model exhibited excellent antibacterial properties, attributed to the chitosan layer. During wound healing in diabetic mice, the MDMN achieved earlier epidermal coverage and faster wound healing through multi-island regeneration centres and the omnidirectional regeneration mode. The MDMN group displayed an accelerated wound healing rate upon arrival at the destination (0.96 % ± 0.58 % vs. 4.61 % ± 0.32 %). Additionally, the MDMN group exhibited superior vascularization and orderly collagen deposition.

CONCLUSION

The present study presents a novel skin regeneration model using microneedles as carriers of autologous keratinocytes and dermal fibroblasts, which allows for omni-directional, multi-center, and full-thickness skin regeneration.

High-Strength Smart Microneedles with "Offensive and Defensive" Effects for Intervertebral Disc Repair

Intervertebral disc degeneration (IVDD) is a global public health issue. The injury of annulus fibrosus (AF) caused by acupuncture or discectomy can trigger IVDD again. However, there is currently no suitable method for treating AF injury. In this study, the high-strength smart microneedles (MNs) which can penetrate the AF tissue through a local and minimally invasive method, and achieve remote control of speeded-up release of the drug and hyperthermia by the Near Infrared is developed. The PDA/GelMA composite MNs loaded with diclofenac sodium are designed to extracellularly "offend" the inflammatory microenvironment and mitigate damage to cells, and intracellularly increase the level of cytoprotective heat shock proteins to enhance the defense against the hostile microenvironment, achieving "offensive and defensive" effects. In vitro experiments demonstrate that the synergistic treatment of photothermal therapy and anti-inflammation effectively reduces inflammation, inhibits cell apoptosis, and promotes the synthesis of the extracellular matrix (ECM). In vivo experiments show that the MNs mitigate the inflammatory response, promote ECM deposition, reduce the level of apoptosis, and restore the biomechanical properties of the intervertebral disc (IVD) in rats. Overall, this high-strength smart MNs display promising "offensive and defensive" effects that can provide a new strategy for IVD repair.

Smart-Responsive Multifunctional Therapeutic System for Improved Regenerative Microenvironment and Accelerated Bone Regeneration via Mild Photothermal Therapy

The treatment of bone defects remains a substantial clinical challenge due to the lack of spatiotemporal management of the immune microenvironment, revascularization, and osteogenic differentiation. Herein, deferoxamine (DFO)-loaded black phosphorus nanosheets decorated by polydopamine layer are prepared (BPPD) and compounded into gelatin methacrylate/sodium alginate methacrylate (GA) hybrid hydrogel as a smart-responsive therapeutic system (GA/BPPD) for accelerated bone regeneration. The BPPD nanocomposites served as bioactive components and near-infrared (NIR) photothermal agents, which conferred the hydrogel with excellent NIR/pH dual-responsive properties, realizing the stimuli-responsive release of DFO and PO4 3 - during bone regeneration. Under the action of NIR-triggered mild photothermal therapy, the GA/BPPD hydrogel exhibited a positive effect on promoting osteogenesis and angiogenesis, eliminating excessive reactive oxygen species, and inducing macrophage polarization to the M2 phenotype. More significantly, through macrophage M2 polarization-induced osteoimmune microenvironment, this hydrogel platform could also drive functional cytokine secretion for enhanced angiogenesis and osteogenesis. In vivo experiments further demonstrated that the GA/BPPD system could facilitate bone healing by attenuating the local inflammatory response, increasing the secretion of pro-healing factors, stimulating endogenous cell recruitment, and accelerating revascularization. Collectively, the proposed intelligent photothermal hydrogel platform provides a promising strategy to reshape the damaged tissue microenvironment for augmented bone regeneration.

Nanoghosts: Harnessing Mesenchymal Stem Cell Membrane for Construction of Drug Delivery Platforms Via Optimized Biomimetics

Mesenchymal stem cells (MSCs) are becoming hotspots for application in disease therapies recently, combining with biomaterials and drug delivery system. A major advantage of MSCs applied in drug delivery system is that these cells enable specific targeting and releasing of cargos to the disease sites. However, the potential tumor tropic effects of MSCs raised concerns on biosafety. To solve this problem, there are emerging methods of isolating cell membranes and developing nanoformulations to perform drug delivery, which avoids concerns on biosafety without disturbing the membrane functions of specific polarizing and locating. These cargoes are so called "nanoghosts." This review article summarizes the current applications of nanoghosts, the promising potential of MSCs to be applied in membrane isolation and nanoghost construction, and possible approaches to develop better drug delivery system harnessing from MSC ghost cell membranes.

Gelatinase-responsive biodegradable targeted microneedle patch for abscess wound treatment of S. aureus infection

Abscess wound caused by bacterial infection is usually difficult to heal, thus greatly affect people's quality of life. In this study, a biodegradable drug-loaded microneedle patch (MN) is designed for targeted eradication of S. aureus infection and repair of abscess wound. Firstly, the bacterial responsive composite nanoparticle (Ce6@GNP-Van) with a size of about 182.6 nm is constructed by loading the photosensitizer Ce6 into gelatin nanoparticle (GNP) and coupling vancomycin (Van), which can specifically target S. aureus and effectively shield the phototoxicity of photosensitizer during delivery. When Ce6@GNP-Van is targeted and enriched in the infected regions, the gelatinase secreted by the bacteria can degrade GNP in situ and release Ce6, which can kill the bacteria by generating ROS under laser irradiation. In vivo experiments show that the microneedle is basically degraded in 10 min after inserting into skin, and the abscess wound is completely healed within 13 d after applying Ce6@GNP-Van-loaded MN patch to the abscess wound of the bacterial infected mice with laser irradiation, which can simultaneously achieve the eradication of biofilm and subsequent wound healing cascade activation, showing excellent synergistic antibacterial effect. In conclusion, this work establishes a synergistic treatment strategy to facilitate the repair of chronic abscess wound.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

ROS-scavenging materials for skin wound healing: advancements and applications

The intricate healing process of skin wounds includes a variety of cellular and molecular events. Wound healing heavily relies on reactive oxygen species (ROS), which are essential for controlling various processes, including inflammation, cell growth, angiogenesis, granulation, and the formation of extracellular matrix. Nevertheless, an overabundance of reactive oxygen species (ROS) caused by extended oxidative pressure may result in the postponement or failure of wound healing. It is crucial to comprehend the function of reactive oxygen species (ROS) and create biomaterials that efficiently eliminate ROS to enhance the healing process of skin wounds. In this study, a thorough examination is presented on the role of reactive oxygen species (ROS) in the process of wound healing, along with an exploration of the existing knowledge regarding biomaterials employed for ROS elimination. In addition, the article covers different techniques and substances used in the management of skin wound. The future prospects and clinical applications of enhanced biomaterials are also emphasized, highlighting the potential of biomaterials that scavenge active oxygen to promote skin repair. This article seeks to enhance the understanding of the complex processes of ROS in the healing of wounds and the application of ROS-scavenging materials. Its objective is to create novel strategies for effective treatment skin wounds.

An Intrinsically Magnetic Epicardial Patch for Rapid Vascular Reconstruction and Drug Delivery

Myocardial infarction (MI) is a major cause of mortality worldwide. The major limitation of regenerative therapy for MI is poor cardiac retention of therapeutics, which results from an inefficient vascular network and poor targeting ability. In this study, a two-layer intrinsically magnetic epicardial patch (MagPatch) prepared by 3D printing with biocompatible materials like poly (glycerol sebacate) (PGS) is designed, poly (ε-caprolactone) (PCL), and NdFeB. The two-layer structure ensured that the MagPatch multifariously utilized the magnetic force for rapid vascular reconstruction and targeted drug delivery. MagPatch accumulates superparamagnetic iron oxide (SPION)-labelled endothelial cells, instantly forming a ready-implanted organization, and rapidly reconstructs a vascular network anastomosed with the host. In addition, the prefabricated vascular network within the MagPatch allowed for the efficient accumulation of SPION-labelled therapeutics, amplifying the therapeutic effects of cardiac repair. This study defined an extendable therapeutic platform for vascularization-based targeted drug delivery that is expected to assist in the progress of regenerative therapies in clinical applications.

The emerging progress on wound dressings and their application in clinic wound management

BACKGROUND

In addition to its barrier function, the skin plays a crucial role in maintaining the stability of the body's internal environment and normal physiological functions. When the skin is damaged, it is important to select proper dressings as temporary barriers to cover the wound, which can exert significant effects on defence against microbial infection, maintaining normal tissue/cell functions, and coordinating the process of wound repair and regeneration. It now forms an important approach in clinic practice to facilitate wound repair.

SEARCH STRATEGIES

We conducted a comprehensive literature search using online databases including PubMed, Web of Science, MEDLINE, ScienceDirect, Wiley Online Library, CNKI, and Wanfang Data. In addition, information was obtained from local and foreign books on biomaterials science and traumatology.

RESULTS

This review focuses on the efficacy and principles of functional dressings for anti-bacteria, anti-infection, anti-inflammation, anti-oxidation, hemostasis, and wound healing facilitation; and analyses the research progress of dressings carrying living cells such as fibroblasts, keratinocytes, skin appendage cells, and stem cells from different origins. We also summarize the recent advances in intelligent wound dressings with respect to real-time monitoring, automatic drug delivery, and precise adjustment according to the actual wound microenvironment. In addition, this review explores and compares the characteristics, advantages and disadvantages, mechanisms of actions, and application scopes of dressings made from different materials.

CONCLUSION

The real-time and dynamic acquisition and analysis of wound conditions are crucial for wound management and prognostic evaluation. Therefore, the development of modern dressings that integrate multiple functions, have high similarity to the skin, and are highly intelligent will be the focus of future research, which could drive efficient wound management and personalized medicine, and ultimately facilitate the translation of health monitoring into clinical practice.

Simvastatin nanocrystals-based dissolving microneedles for wound healing

Currently, one of the main problems encountered in wound healing therapy is related to inefficient drug delivery. However, dissolving microneedles (DMNs) can be administered percutaneously to effectively deliver a drug to a deep wound area. Simvastatin (SIM) can promote wound healing, albeit its insolubility in water limits its application. Here, we designed a DMNs (SIM-NC@DMNs) drug delivery system loaded with SIM nanocrystals (SIM-NC) and evaluated its efficacy in wound healing. Based on our observations, the dissolution performance of insoluble SIM is significantly improved after the preparation of SIM-NC. For example, the saturation solubility of SIM-NC in deionized water and PBS increased by 150.57 times and 320.14 times, respectively. After the SIM-NC@DMNs are deeply inserted into the wound, the needle portion, which is composed of hyaluronic acid (HA), dissolves rapidly, and the SIM-NC loaded on the needle portion is efficiently released into the deep wound area for optimal therapeutic efficacy. The combination of NC and DMNs makes this system further effective for wound healing. Our cumulative work suggests that the newly developed SIM-NC@DMNs possess great potential in accelerating wound healing. By day 12 after treatment, the residual wound area in the Control group was 21.34 %, while the residual wound area in the SIM-NC@DMNs group was only 2.36 %. This result as well as provides certain evidence of its efficacy for wound healing therapy. The SIM-NC@DMNs drug delivery system may become an efficient treatment modality that promotes wound healing, with a promising potential in the field of wound healing research.

Advanced Silk Fibroin Biomaterials-Based Microneedles for Healthcare

Microneedles are a promising transdermal drug delivery system that has the advantages of minimal invasiveness, painlessness, and on-demand drug delivery compared with commonly used medical techniques. Natural resources are developed as next-generation materials for microneedles with varying degrees of success. Among them, silk fibroin is a natural polymer obtained from silkworms with good biocompatibility, high hardness, and controllable biodegradability. These properties provide many opportunities for integrating silk fibroin with implantable microneedle systems. In this review, the research progress of silk fibroin microneedles in recent years is summarized, including their materials, processing technology, detection, drug release methods, and applications. Besides, the research and development of silk fibroin in a multidimensional way are analyzed. Finally, it is expected that silk fibroin microneedles will have excellent development prospects in various fields.

Ultrarapid-Acting Microneedles for Immediate Delivery of Biotherapeutics

Subcutaneous (SC) injection is a common administration route for rapid and efficient delivery of biotherapeutics. However, syringe-based injections usually require professional assistance and are associated with pain and potential risks of infections, thus leading to undesired patient compliance and poor life quality. Herein, this work presents an ultrarapid-acting microneedle (URA-MN) patch for immediate transdermal delivery of therapeutics in a minimally invasive manner. Effervescent agents are incorporated into the tip of URA-MN for rapid generation of CO2 bubbles upon insertion into the skin, immediately powering the biotherapeutics release within a few minutes. The release kinetics of diverse agents including liraglutide (LRT), insulin, and heparin from the URA-MN patches are evaluated in three different mouse models, and the rapid release of biotherapeutics and potent therapeutic effects are achieved with only 5 min administration. Noteworthily, attributed to the short application duration and negligible residuals of MN matrix remaining in the skin, the URA-MN patch shows desirable biocompatibility after six-week administration.

Combination therapy using multifunctional dissolvable hyaluronic acid microneedles for oral ulcers

Oral ulcers are common in the oral mucosa. Frequent occurrences of oral ulcers commonly afflict patients, seriously impacting their daily life. Treatments with good anti-inflammatory and antibacterial properties are important for promoting the healing of oral ulcers. In this study, a multifunctional, soluble hyaluronic acid (HA) microneedle (MN) patch was prepared to promote oral ulcer healing. The tip layer of the MN patch was loaded with triamcinolone acetonide (TA) and epidermal growth factor (EGF) to inhibit inflammation and promote angiogenesis. Zeolitic imidazolate framework-8 (ZIF-8) was loaded onto the base layer of the MN patch, which effectively released Zn2+ to mediate antibacterial effects. In addition, HA exerts a protective effect on the mucous membrane. Owing to these properties, the multifunctional MN patches were found to have good anti-inflammatory, antibacterial, and tissue-healing abilities, indicating that the multifunctional MN patch design successfully promoted the healing of oral ulcers.

Layer-by-layer microneedle patch with antibacterial and antioxidant dual activities for accelerating bacterial-infected wound healing

Bacterial-infected wound healing has always been a huge challenge to humans. Owing to the appearance of antibiotic resistance, there is an emergency need to design antibiotic-free wound dressings to treat such wounds. Herein, a novel antibiotic-free microneedle patch was designed, which its backing layer with antioxidant effect was coated with sodium carboxymethyl cellulose, 2-O-α-D-glucopyranosyl-L-ascorbic acid (GLAA), and 2-hydroxypropyltrimethyl ammonium chloride chitosan through electrostatic interaction based on layer-by-layer self-assembly technique, and its tips consisted of gelatin and tannic acid (TA) via hydrogen bonding interaction (CGH/GTA MN patch). The obtained CGH/GTA MN patch could effectively puncture the skin, and exhibit properties of pH-responsive TA and GLAA release. In vitro experiments showed that the obtained CGH/GTA MN patch has excellent antioxidative (scavenging DPPH efficacy is above 80 %, and scavenging ABTS efficiency reaches about 100 %), antibacterial (antibacterial rates of nearly 100 % for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)), biodegradable, and biocompatible properties. In the S. aureus-infected rat wounds, the CGH/GTA MN patch could efficiently accelerate infected-wound healing by eliminating S. aureus infection, inhibiting inflammation, promoting angiogenesis, and accelerating epidermal regeneration. Thus, this study will provide a promising strategy to heal bacterial-infected wounds.

A Strong Adhesive Biological Hydrogel for Colon Leakage Repair and Abdominal Adhesion Prevention

Colon leakage is one of the most severe complications in abdominal trauma or surgery cases. It can lead to severe abdominal infection and abdominal adhesions, resulting in prolonged hospital stays and increased mortality. In this study, a photosensitive hydrogel is proposed, which can swiftly form a strong adhesion coating on the damaged colon after UV irradiation, to realize quick cure and suture-free repair of colon leakage. The newly developed biological gel consists of hyaluronic acid methacryloyl (HAMA) and hyaluronic acid o-nitroso benzaldehyde (HANB) in the optimal ratio of 3: 1, which exerts both the rapid photocuring properties of HAMA and the strong tissue adhesion properties of HANB. HAMA/HANB shows excellent adhesion stability on wet surfaces, presenting controllable mechanical properties, ductility, adhesion stability, and chemical stability; it also evades foreign body response, which relieves the degree of abdominal adhesion. The underlying mechanism for HAMA/HANB promoting wound healing in colon leakage involves the reconstruction of the colon barrier, as well as the regulation of the immune reaction and neovascularization. In all, HAMA/HANB is a promising alternative suture-free approach for repairing colon leakage; it has a reliable healing effect and is expected to be extended to clinical application for other organ injuries.

Functional Microneedle Patch for Wound Healing and Biological Diagnosis and Treatment

Wound healing, especially chronic wounds, has been one of the major challenges in the field of biomedicine. Drug therapy alone is not effective, so a variety of functional wound healing dressings have been developed. Microneedles have attracted more and more attentions in the field of wound healing dressings due to their penetration and high drug delivery efficiency. In this review, all the studies on the application of microneedles in wound healing in recent years are summarized, classify different microneedles according to their functions in the process of wound healing, discuss the current challenges in the transformation of microneedle technology toward clinical applications, and finally look forward to the future design and development directions of microneedles in this field.

Microneedle systems: cell, exosome, and nucleic acid based strategies

Cells, exosomes, and nucleic acids play crucial roles in biomedical engineering, holding substantial clinical potential. However, their utility is often hindered by various drawbacks, including cellular immunogenicity, and instability of exosomes and nucleic acids. In recent years, microneedle (MN) technology has revolutionized drug delivery by offering minimal invasiveness and remarkable versatility. MN has emerged as an ideal platform for the extraction, storage, and delivery of these biological components. This review presents a comprehensive overview of the historical progression and recent advances in the field of MN. Specifically, it highlights the current applications of cell-, exosome-, and nucleic acid-based MN systems, while presenting prevailing research challenges. Additionally, the review provides insights into the prospects of MN in this area, aiming to provide new ideas for researchers and facilitate the clinical translation of MN technology.

The Progress in the Application of Dissolving Microneedles in Biomedicine

In recent years, microneedle technology has been widely used for the transdermal delivery of substances, showing improvements in drug delivery effects with the advantages of minimally invasive, painless, and convenient operation. With the development of nano- and electrochemical technology, different types of microneedles are increasingly being used in other biomedical fields. Recent research progress shows that dissolving microneedles have achieved remarkable results in the fields of dermatological treatment, disease diagnosis and monitoring, and vaccine delivery, and they have a wide range of application prospects in various biomedical fields, showing their great potential as a form of clinical treatment. This review mainly focuses on dissolving microneedles, summarizing the latest research progress in various biomedical fields, providing inspiration for the subsequent intelligent and commercial development of dissolving microneedles, and providing better solutions for clinical treatment.

Hyaluronic Acid-Conjugated Fluorescent Probe-Shielded Polydopamine Nanomedicines for Targeted Imaging and Chemotherapy of Bladder Cancer

Bladder cancer is one of the most common malignancies in the urinary system, with high risk of recurrence and progression. However, the difficulty in detecting small tumor lesions and the lack of selectivity of intravesical treatment seriously affect the prognosis of patients with bladder cancer. In the present work, a nanoparticle-based delivery system with tumor targeting, high biocompatibility, simple preparation, and the ability to synergize imaging and therapy was fabricated. Specifically, this nanosystem consisted of the core of doxorubicin (DOX)-loaded polydopamine nanoparticles (PDD NPs) and the shell of hyaluronic acid (HA)-conjugated IR780 (HA-IR780). The HA-IR780-covered PDD NPs (HR-PDD NPs) demonstrated tumor targeting and visualization both in vitro and in vivo with properties of promoted cancer cell endocytosis and lysosomal escape, efficiently delivering drugs to the target site and exerting a killing effect on tumor cells. Encouragingly, intravesical instillation of HR-PDD NPs improved drug retention in the bladder and promoted its accumulation in tumor tissue, resulting in better tumor proliferation inhibition and apoptosis in an orthotopic bladder cancer model in rats. This study provides a promising strategy for the diagnosis and therapy of bladder cancer.

Reactive Oxygen Species-Scavenging Nanosystems in the Treatment of Diabetic Wounds

Diabetic wounds are characterized by drug-resistant bacterial infections, biofilm formation, impaired angiogenesis and perfusion, and oxidative damage to the microenvironment. Given their complex nature, diabetic wounds remain a major challenge in clinical practice. Reactive oxygen species (ROS), which have been shown to trigger hyperinflammation and excessive cellular apoptosis, play a pivotal role in the pathogenesis of diabetic wounds. ROS-scavenging nanosystems have recently emerged as smart and multifunctional nanomedicines with broad synergistic applicability. The documented anti-inflammatory and pro-angiogenic ability of ROS-scavenging treatments predestines these nanosystems as promising options for the treatment of diabetic wounds. Yet, in this context, the therapeutic applicability and efficacy of ROS-scavenging nanosystems remain to be elucidated. Herein, the role of ROS in diabetic wounds is deciphered, and the properties and strengths of nanosystems with ROS-scavenging capacity for the treatment of diabetic wounds are summarized. In addition, the current challenges of such nanosystems and their potential future directions are discussed through a clinical-translational lens.