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

Bioinspired conductive oriented nanofiber felt with efficient ROS clearance and anti-inflammation for inducing M2 macrophage polarization and accelerating spinal cord injury repair

Complete spinal cord injury (SCI) causes permanent locomotor, sensory and neurological dysfunctions. Targeting complex immunopathological microenvironment at SCI sites comprising inflammatory cytokines infiltration, oxidative stress and massive neuronal apoptosis, the conductive oriented nanofiber felt with efficient ROS clearance, anti-inflammatory effect and accelerating neural regeneration is constructed by step-growth addition polymerization and electrostatic spinning technique for SCI repair. The formation of innovative Fe3+-PDA-PAT chelate in nanofiber felt enhances hydrophilic, antioxidant, antibacterial, hemostatic and binding factor capacities, thereby regulating immune microenvironment of SCI. With the capabilities of up-regulating COX5A and STAT6 expressions, down-regulating the expressions of IL1β, CD36, p-ERK, NFκB2 and NFκB signaling pathway proteins, the nanofiber felt attenuates oxidative stress injury, promotes M2 macrophage polarization and down-regulates inflammatory response. After implantation into complete transection SCI rats, the nanofiber felt is revealed to recruit endogenous NSCs, induce the differentiation of NSCs into neurons while inhibit astrocytes formation and inflammation, reduces glia scar, and promotes angiogenesis, remyelination and neurological functional recovery. Overall, this innovative strategy provides a facile immune regulatory system to inhibit inflammatory response and accelerate nerve regeneration after SCI, and its targeted proteins and mechanisms are first elucidated, which holds great application promise in clinical treatment of complete SCI.

In situ photocrosslinkable hydrogel treats radiation-induced skin injury by ROS elimination and inflammation regulation

The clinical management of radiation-induced skin injury (RSI) poses a significant challenge, primarily due to the acute damage caused by an overabundance of reactive oxygen species (ROS) and the ongoing inflammatory microenvironment. Here, we designed a dual-network hydrogel composed of 5 % (w/v) Pluronic F127 diacrylate and 2 % (w/v) hyaluronic acid methacryloyl, termed the FH hydrogel. To confer antioxidant and anti-inflammation properties to the hydrogel, we incorporated PVP-modified Prussian blue nanoparticles (PPBs) and resveratrol (Res) to form PHF@Res hydrogels. PHF@Res hydrogels not only exhibited multiple free radical scavenging activities (DPPH, ABTS), but also displayed multiple enzyme-like activities (POD-, catalase). Meanwhile, PHF@Res-2 hydrogels significantly suppressed intracellular ROS and promoted the migration of fibroblasts in a high-oxidative stress environment. Moreover, in the RSI mouse model, the PHF@Res-2 hydrogel regulated inflammatory factors and collagen deposition, significantly reduced epithelial hyperplasia, promoted limb regeneration and neovascularization, and accelerated wound healing, outperforming the commercial antiradiation formulation, Kangfuxin. The PHF@Res-2 hydrogel dressing shows great potential in accelerating wound healing in RSI, offering tremendous promise for clinical wound management and regeneration.

2D Janus carrier-enabled trojan horse: Gallium delivery for the sequential therapy of biofilm associated infection

Biofilm-associated infections (BAIs) continue to pose a major challenge in the medical field. Nanomedicine, in particular, promises significant advances in combating BAIs through the introduction of a variety of nanomaterials and nano-antimicrobial strategies. However, studies to date have primarily focused on the removal of the bacterial biofilm and neglect the subsequent post-biofilm therapeutic measures for BAIs, rendering pure anti-biofilm strategies insufficient for the holistic recovery of affected patients. Herein, we construct an emerging dual-functional composite nanosheet (SiHx@Ga) that responds to pHs fluctuation in the biofilm microenvironment to enable a sequential therapy of BAIs. In the acidic environment of biofilm, SiHx@Ga employs the self-sensitized photothermal Trojan horse strategy to effectively impair the reactive oxygen species (ROS) defense system while triggering oxidative stress and lipid peroxidation of bacteria, engendering potent antibacterial and anti-biofilm effects. Surprisingly, in the post-treatment phase, SiHx@Ga adsorbs free pathogenic nucleic acids released after biofilm destruction, generates hydrogen with ROS-scavenging and promotes macrophage polarization to the M2 type, effectively mitigating damaging inflammatory burst and promoting tissue healing. This well-orchestrated strategy provides a sequential therapy of BAIs by utilizing microenvironmental variations, offering a conceptual paradigm shift in the field of nanomedicine anti-infectives.

An antibacterial, antioxidant and hemostatic hydrogel accelerates infectious wound healing

Hydrogel drug-delivery system that can effectively load antibacterial drugs, realize the in-situ drug release in the microenvironment of wound infection to promote wound healing. In this study, a multifunctional hydrogel drug delivery system (HA@TA-Okra) was constructed through the integration of hyaluronic acid methacrylate (HAMA) matrix with tannic acid (TA) and okra extract. The composition and structural characteristics of HA@TA-Okra system and its unique advantages in the treatment of diverse wounds were systematically evaluated. TA, due to its unique chemical structure, is able to anchor within the HAMA network through interactions and cross-linking, conferring exceptional mechanical strength and stability to the hydrogel. Both TA and okra extract possess antioxidant and antibacterial properties, and when they two acts synergistically they can effectively scavenge free radicals, enhance antibacterial action, diminishing the risk of wound infection. In vitro experiments revealed that HA@TA-Okra system has superior properties, such as rapid gel response, remarkable swelling regulation, and potent antioxidant ability. Furthermore, the HA@TA-Okra system significantly outperformed conventional dressings in terms of hemostatic performance in a rat hemorrhage model. We further evaluated the repair role of HA@TA-Okra system in vivo by establishing an animal model of full-thickness skin defects and a model of infected total skin defects. The results confirmed its positive effects in fighting bacterial infection, reducing inflammation and promoting wound healing. In summary, the HA@TA-Okra system exhibits comprehensive properties such as antibacterial, antioxidant and hemostatic properties, which has a potential application in the field of tissue repair medicine.

Spontaneously Photocatalytic Nanoplatform for Sensitive Diagnosis and Penetrated Therapy of Cancer

In this study, a sensitive diagnosis and spontaneously photocatalytic therapy of cancer based on chemiluminescence (CL) and nanozyme was studied. Briefly, carbon nitride-supported copper nanoparticles (CuCNs) loaded with luminol (CuCN-L) were utilized to develop a microneedle patch (CuCN-L/MN). The CuCN-L probe could target overexpressed H2O2 in the TME and actively emit CL to achieve cancer cell imaging for diagnosis. In addition, 425 nm blue-violet CL could photocatalyze CuCN to reduce carbon dioxide (CO2) to carbon monoxide (CO) for gas therapy (GT). Meanwhile, CuCN, acting as a photosensitizer (PS), could be activated by CL to produce reactive oxygen species (ROS), which realized photodynamic therapy (PDT). Furthermore, the use of a degradable MN based on hyaluronic acid (HA) promotes painless local administration as well as deep administration of GT and PDT. This technology of optical sensor-mediated anticancer treatment will have great potential to provide new inspirations for cancer diagnosis and therapy based on a self-excited nanoplatform.

Reactive Oxygen Species-Responsive Gel-Based Microneedle Patches with Antimicrobial and Immunomodulating Properties for Oral Mucosa Disease Treatment

Oral ulcer wounds are difficult to heal due to bacterial infections, persistent inflammatory responses, and excessive reactive oxygen species (ROS). Therefore, the elimination of bacteria, removal of ROS, and reduction of inflammation are prerequisites for the treatment of mouth ulcer wounds. In this study, oligomeric proanthocyanidins (OPC) and 3-(aminomethyl)phenylboronic acid-modified hyaluronic acid (HP) were used to form polymer gels through dynamic covalent borate bonds. Minocycline hydrochloride (MH) was then loaded into the polymer gel, and a multifunctional MH/OPC-HP microneedles (MNs) with ROS-responsive properties was prepared using a vacuum method. The MH/OPC-HP MNs can rapidly release MH in a diffusive manner and sustainably release OPC in response to ROS. The gel-based MH/OPC-HP MNs extended the retention of OPC in oral ulcers, leading to prolonged ROS scavenging effects. Cytocompatibility and hemocompatibility tests showed that MH/OPC-HP MNs had good biocompatibility. Antibacterial experiments demonstrated that MNs loaded with MH exhibited excellent antibacterial effects. In vitro experiments indicated that MH/OPC-HP MNs could effectively clear ROS, reduce oxidative stress damage, inhibit M1-type macrophage polarization, and induce M2-type polarization. Furthermore, in vivo experiments revealed that MH/OPC-HP MNs could inhibit pro-inflammatory cytokines, promote neovascularization, accelerate epithelial healing of ulcers, and significantly promote healing in a rat model of oral ulcer wound infection. In summary, MH/OPC-HP MNs hold promise as a therapeutic strategy for enhancing the healing of oral ulcer wounds.

Microneedle patches: a new vantage point for diabetic wound treatments

Microneedle patches have emerged as a promising approach for diabetic wound healing by enabling the targeted delivery of therapeutic agents such as stem cells and their derived exosomes, as well as localized delivery of bioactive moieties. These patches offer a non-invasive and efficient method for administering therapeutic payloads directly to the site of the wound, bypassing systemic circulation and minimizing potential side effects. The targeted delivery of stem cells holds immense potential for promoting tissue regeneration and accelerating wound healing in diabetic patients. Similarly, the localized delivery of stem cell-derived exosomes, which are known for their regenerative and anti-inflammatory properties, can enhance the healing process. Furthermore, microneedle patches enable the precise and controlled release of bioactive moieties, such as growth factors and cytokines, directly to the wound site, creating a conducive microenvironment for tissue repair and regeneration. The challenges associated with microneedle patches for diabetic wound healing are multifaceted. Biocompatibility issues, variability in skin characteristics among diabetic patients, regulatory hurdles, scalability, cost considerations, long-term stability, and patient acceptance and compliance all present significant barriers to the widespread adoption and optimization of microneedle technology in clinical practice. Overcoming these challenges will require collaborative efforts from various stakeholders to advance the field and address critical gaps in research and development. Ongoing research focuses on enhancing the biocompatibility and mechanical properties of microneedle materials, developing customizable technologies for personalized treatment approaches, integrating advanced functionalities such as sensors for real-time monitoring, and improving patient engagement and adherence through education and support mechanisms. These advancements have the potential to improve diabetic wound management by providing tailored and precise therapies that promote faster healing and reduce complications. This review explores the current landscape of microneedle patches in the context of diabetic wound management, highlighting both the challenges that need to be addressed and future perspectives for this innovative treatment modality.

The pursuit of linear dosage in pharmacy: reservoir-based drug delivery systems from macro to micro scale

INTRODUCTION

The pursuit of linear dosage in pharmacy is essential for achieving consistent therapeutic release and enhancing patient compliance. This review provides a comprehensive summary of zero-order drug delivery systems, with a particular focus on reservoir-based systems emanated from different microfabrication technologies.

AREAS COVERED

The consideration of recent advances in drug delivery systems is given to encompass the key areas including the importance of achieving a constant drug release rate for therapeutic applications. Detailed examination of reservoir-based systems, their design, mechanisms of action and materials used are highlighted. By addressing these areas, the discussion aims to provide a thorough understanding of most recent zero-order drug delivery systems, their performance advantages and methods of their manufacturing. To ensure the complete coverage of the explored research area, modern AI-assistant tools were used to find not only the most relevant, but also connected and similar articles.

EXPERT OPINION

Future developments in reservoir-based drug delivery systems are expected to significantly enhance therapeutic effectiveness and patient outcomes through the integration of innovative materials and technologies. The fabrication of intelligent drug delivery systems that utilize sensors and feedback mechanisms can enable real-time monitoring of drug release and patient reactions.

Therapeutic Potential of Microneedle Assisted Drug Delivery for Wound Healing: Current State of the Art, Challenges, and Future Perspective

Microneedles (MNs) appear as a transformative and minimally invasive platform for transdermal drug delivery, representing a highly promising strategy in wound healing therapeutics. This technology, entailing the fabrication of micron-scale needle arrays, enables the targeted and efficient delivery of bioactive agents into the epidermal and dermal layers without inducing significant pain or discomfort. The precise penetration of MNs facilitates localized and sustained drug release, which significantly enhances tissue regeneration and accelerates wound closure. Furthermore, MNs can be engineered to encapsulate essential bioactive compounds, including antimicrobial agents, growth factors, and stem cells, which are critical for modulating the wound healing cascade and mitigating infection risk. The biodegradable nature of these MNs obviates the need for device removal, rendering them particularly advantageous in the management of chronic wounds such as diabetic ulcers and pressure sores. The integration of nanotechnology within MNs further augments their drug-loading capacity, stability, and controlled-release kinetics, offering a sophisticated therapeutic modality. This cutting-edge approach has the potential to redefine wound care by optimizing therapeutic efficacy, reducing adverse effects, and enhancing patient adherence. As MN technology advances, its application in wound healing exemplifies a dynamic frontier within biomedical engineering and regenerative medicine.

The Synergistic Potential of Hydrogel Microneedles and Nanomaterials: Breaking Barriers in Transdermal Therapy

The stratum corneum, which acts as a strong barrier against external agents, presents a significant challenge to transdermal drug delivery. In this regard, microneedle (MN) patches, designed as modern systems for drug delivery via permeation through the skin with the ability to pass through the stratum corneum, are known to be convenient, painless, and effective. In fact, MN have shown significant breakthroughs in transdermal drug delivery, and among the various types, hydrogel MN (HMNs) have demonstrated desirable inherent properties. Despite advancements, issues such as limited loading capacity, uncontrolled drug release rates, and non-uniform therapeutic approaches persist. Conversely, nanomaterials (NMs) have shown significant promise in medical applications, however, their efficacy and applicability are constrained by challenges including poor stability, low bioavailability, limited payload capacity, and rapid clearance by the immune system. Incorporation of NMs within HMNs offers new prospects to address the challenges associated with HMNs and NMs. This combination can provide a promising field of research for improved and effective delivery of therapeutic agents and mitigate certain adverse effects, addressing current clinical concerns. The current review highlights the use of NMs in HMNs for various therapeutic and diagnostic applications.

Engineered Nanoparticles for Theranostic Applications in Kidney Repair

Kidney diseases are characterized by their intricate nature and complexity, posing significant challenges in their treatment and diagnosis. Nanoparticles (NPs), which can be further classified as synthetic and biomimetic NPs, have emerged as promising candidates for treating various diseases. In recent years, the development of engineered nanotherapeutics has focused on targeting damaged tissues and serving as drug delivery vehicles. Additionally, these NPs have shown superior sensitivity and specificity in diagnosis and imaging, thus providing valuable insights for the early detection of diseases. This review aims to focus on the application of engineered synthetic and biomimetic NPs in kidney diseases in the aspects of treatment, diagnosis, and imaging. Notably, the current perspectives and challenges are evaluated, which provide inspiration for future research directions, and encourage the clinical application of NPs in this field.

A review on recent advances in polymeric microneedle loading cells: Design strategies, fabrication technologies, transdermal application and challenges

Microneedle systems (MNs) loading living cells are a powerful platform to treat various previously incurable diseases in the era of precision medicine. Herein, an overview of recent advances in MN-based strategies for cell delivery is summarized, including material selection, design of morphological structures, and processing methods. We also systematically outlined the law of microstructural design relative to the structure-effective/function relationship in transdermal delivery or precision medicine and the design principles of cell microneedle (CMN). Furthermore, the representative works of precision treatments focusing on inflammatory skin diseases were tracked and discussed using CMN. Indeed, it highlights a practical path to solving the dilemma of cell therapy and raising the hope of precision medicine. However, there are still some challenges in developing CMN since they need multi-dimensional comprehensive properties, including mechanical properties, cell viability preservation, release, therapeutic effect, etc. The manuscript could provide insights into developing an innovative fit-to-purpose vehicle in cell therapy for interested researchers.

Hierarchically Porous Microgels with Interior Spiral Canals for High-Efficiency Delivery of Stem Cells in Wound Healing

Chronic wound poses a serious risk to diabetic patients, primarily due to damaged skin microvasculature and prolonged inflammation at the wound site. Mesenchymal stem cell (MSC) therapy utilizing microgels as a cell delivery system has shown promise in promoting wound healing by enhancing cell viability and the secretion of bioactive factors. Retaining sufficient MSCs at injury sites is crucial for optimal therapeutic outcomes. However, inadequate hierarchical structure and limited use of the microgel's interior space significantly reduce cell proliferation and infiltration efficiency, thereby compromising the therapeutic effect. To address this, a microfluidic approach is developed for fabricating porous hierarchical interconnected microgels with interior spiral canals (PHIGels) by employing a fluidic "viscous instability" effect and gas formation reaction during the microfluidic synthesis. These MSC-laden PHIGel scaffolds facilitate rapid proliferation and infiltration into the interior spiral canals through a hierarchical pore network, significantly increasing the number of viable cells that can be carried by the microgels. It is proved that these microgel-based deliveries of MSCs promote re-epithelialization, collagen synthesis, angiogenesis, and reduction in inflammation, thus enhancing cutaneous wound repair in a rat model of type I diabetes. The microporosity and hierarchical design of these microgels offer novel routes for tissue regeneration and repair.

Trojan Horse Bioheterojunction Empowers Adhesive Hydrogel with Robust Antibacterial Activity and Sensing Capacity for Infected Cutaneous Regeneration

Strategic integration of adhesive hydrogels with phototherapy-based antibacterial properties has been extensively leveraged in infected tissue repair. Nevertheless, the interference of bacterial heat shock proteins and antioxidant defense systems attenuates the bactericidal potency of phototherapy. To address this imposing predicament, a Trojan horse bioheterojunction (Th-bioHJ) incorporating liquid metal and copper sulfide is devised to confer an adhesive hydrogel with multimodal and comprehensive antibacterial properties for remedying infectious wounds. Th-bioHJ generates phototherapeutic effects and interrupts the electron transport chain with the Trojan horse strategy, achieving rapid and robust sterilization. Additionally, Th-bioHJ promotes cell migration and angiogenesis. In vivo studies elucidate the remarkable efficacy of Th-bioHJ hydrogel in rapidly eradicating bacteria, promoting angiogenesis and boosting infectious cutaneous regeneration. Meanwhile, the Th-bioHJ hydrogel demonstrates exceptional biointerface adhesion and sensing capabilities for real-time motion monitoring. This study provides groundbreaking insights into the innovative application of an adhesive hydrogel in the management of infected wounds.

Multifunctional Microneedle Patches Loaded With Engineered Nitric Oxide-Releasing Nanocarriers for Targeted and Synergistic Chronic Wound Therapy

Chronic wounds impose significant physical and mental burdens on patients. Nano-based formulations offer a promising strategy for chronic wound healing due to their non-invasive nature and enhanced biofilms penetration, but they often lack targeting capability or fail to achieve long-term and synergistic effects. In this work, a multifunctional microneedle (MN) patch loaded with engineered nitric oxide (NO)-releasing nanocarriers are presented that encapsulate an antibacterial agent and are immobilized with Concanavalin A (Con A) and NO molecules for targeted and synergistic treatment of chronic wounds. With the assistance of MNs, the nanoparticles (NPs) can directly cross bacterial biofilms and be efficiently delivered to wound tissues, where they target harmful bacteria through the specific recognition between Con A and polysaccharides on bacterial surfaces, followed by the release of the encapsulated antimicrobial agent, thereby achieving effective antibacterial effect. Moreover, the NPs generate NO in a sustained manner as they dissociate in the wound tissue, which exerts potent anti-inflammatory action and benefits tissue regeneration, further promoting chronic wounds closure. Consequently, this work provides a novel MN patch loaded with engineered NPs designed for accelerating chronic wound healing through targeted and synergistic therapy.

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.

Near Infrared-Triggered Nitric Oxide-Release Nanovesicles with Mild-Photothermal Antibacterial and Immunomodulation for Healing MRSA-Infected Diabetic Wounds

Bacterial infection-induced excessive inflammation is a major obstacle in diabetic wound healing. Nitric oxide (NO) exhibits significant antibacterial activity but is extremely deficient in diabetes. Hence, a near-infrared (NIR)-triggered NO release system is constructed through codelivery of polyarginine (PArg) and gold nanorods (Au) in an NIR-activatable methylene blue (MB) polypeptide-assembled nanovesicle (Au/PEL-PBA-MB/PArg). Upon NIR irradiation, the quenched MB in the nanovesicles is photoactivated to generate more reactive oxygen species (ROS) to oxidize PArg and release NO in an on-demand controlled manner. With the specific bacterial capture of phenylboronic acid (PBA), NO elevated membrane permeability and boosted bacterial vulnerability in the photothermal therapy (PTT) of the Au nanorods, which is displayed by superior mild PTT antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) at temperatures < 49.7 °C in vitro. Moreover, in vivo, the antibacterial nanovesicles greatly suppressed the burst of MRSA-induced excessive inflammation, NO relayed immunomodulated macrophage polarization from M1 to M2, and the excessive inflammatory phase is successfully transferred to the repair phase. In cooperation with angiogenesis by NO, tissue regeneration is accelerated in MRSA-infected diabetic wounds. Therefore, nanoplatform has considerable potential for accelerating the healing of infected diabetic wounds.

Drug-phospholipid conjugate nano-assembly for drug delivery

Phospholipid-based liposomes are among the most successful nanodrug delivery systems in clinical use. However, these conventional liposomes present significant challenges including low drug-loading capacity and issues with drug leakage. Drug-phospholipid conjugates (DPCs) and their assemblies offer a promising strategy for addressing these limitations. In this review, we summarize recent advances in the design, synthesis, and application of DPCs for drug delivery. We begin by discussing the chemical backbone structures and various design strategies such as phosphate head embedding and mono-/bis-embedding in the sn-1/sn-2 positions. Furthermore, we highlight stimulus-responsive designs of DPCs and their applications in treating diseases such as cancer, inflammation, and malaria. Lastly, we explore future directions for DPCs development and their potential applications in drug delivery.

Microneedles as transdermal drug delivery system for enhancing skin disease treatment

Microneedles (MNs) serve as a revolutionary paradigm in transdermal drug delivery, heralding a viable resolution to the formidable barriers presented by the cutaneous interface. This review examines MNs as an advanced approach to enhancing dermatological pathology management. It explores the complex dermis structure and highlights the limitations of traditional transdermal methods, emphasizing MNs' advantage in bypassing the stratum corneum to deliver drugs directly to the subdermal matrix. The discourse outlines the diverse typologies of MNs, including solid, coated, hollow, hydrogel, and dissolvable versions. Each type is characterized by its unique applications and benefits. The treatise details the deployment of MNs in the alleviation of cutaneous cancers, the administration of inflammatory dermatoses such as psoriasis and atopic dermatitis, and their utility in wound management. Additionally, the paper contemplates the prospects of MNs within the realm of aesthetic dermatology and the burgeoning market traction of cosmetic MN formulations. The review summarizes the scientific and commercial challenges to the clinical adoption of MN therapeutics, including dosage calibration, pharmacodynamics, biocompatibility, patient compliance, sterilization, mass production, and regulatory oversight. It emphasizes the need for ongoing research, innovation, and regulatory harmonization to overcome these obstacles and fully realize MNs' potential in treating skin diseases and improving patient welfare.

Biofabricated osteoblast-derived nanovesicles as extracellular vesicle mimics for bone repair

Osteoblast-derived extracellular vesicles (EVs) have demonstrated therapeutic utility for bone repair as transporters of key biomolecules capable of accelerating biomineralisation and tissue repair. The clinical translation of these biologically derived nanoparticles, however remains limited due to scalability, heterogeneity and standardisation issues. Herein we investigate the generation of nanovesicles (NVs) from mineralising osteoblasts by extrusion directly compared against natural EV counterparts from the same parental cells. Mineralising osteoblast-derived EVs (MO-EVs) were isolated via ultracentrifugation from cell culture media. The parental osteoblasts were then processed via serial extrusion to <200 nm. EVs and NVs were characterised by comparing their size, concentration and morphology. The presence of tetraspanin markers was detected by Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS). Osteoblasts viability and metabolic activity was assessed after both EV and NV-treatment before comparing their mineralising potency via alizarin red staining. EVs and NVs exhibited similar diameters of approximately 100 nm with a vesicular morphology. EVs were found to be richer in proteins and exhibited a significantly more negative ζ-potential compared to NVs. SP-IRIS analysis confirmed the presence of CD9, CD63 and CD81 in EVs. At both 1 and 10 μg/mL, EVs and NVs reduced the metabolic activity of osteoblasts, however, this was not associated with any cytotoxic effects. The biomineralisation study performed using osteoblasts showed that only EVs significantly increased mineral deposition (p < 0.05) compared to untreated control. In this study, we have established for the first time the biofabrication of cell-derived nanovesicles as a promising alternative to extracellular vesicles derived from mineralising osteoblasts.

Exploring the wound healing potential of dietary nitrate in diabetic rat model

Introduction

The wound healing in diabetes is hindered and prolonged due to long-term inflammation, oxidative stress damage, and angiogenesis disorders induced by high glucose status. The management of such difficult-to-treat wounds continues to pose a significant challenge in clinical treatment. Dietary nitrate, commonly found in greens such as beets and spinach, acts as a nutritional supplement and is metabolized in the body through the salivary nitrate-nitrite-NO pathway. This pathway plays a crucial role in various physiological functions, including enhancing blood flow and attenuating inflammation.

Methods

In this study, we established a diabetic rat wound model. Forty-eight rats were randomly divided into six groups (n = 8): the Con group, the Con + Nitrate group, the STZ group, the STZ + NaCl group, the STZ + rhEGF group, and the STZ + Nitrate group. Skin wound healing was assessed on the day of surgery and on postoperative days 3, 7, 10, and 14. Specimens were taken on days 7 and 14 post-surgery for relevant tests.

Results

We found that dietary nitrate could accelerate skin wound healing by promoting angiogenesis and increasing blood perfusion. Significantly, dietary nitrate also regulated glucose and lipid metabolism and exhibited anti-inflammatory and antioxidant properties.

Discussion

These findings provide a novel theoretical basis for managing wounds in diabetic individuals, indicating the broad potential of dietary nitrate in future clinical applications.

Drug-Loaded Mesoporous Polydopamine Nanoparticles in Chitosan Hydrogels Enable Myocardial Infarction Repair through ROS Scavenging and Inhibition of Apoptosis

In this study, we synthesized mesoporous polydopamine nanoparticles (MPDA NPs) using an emulsion-induced interface assembly strategy and loaded epigallocatechin gallate (EGCG) into MPDA NPs via electrostatic attraction to form EGCG@MPDA NPs. In the post myocardial infarction (MI) environment, these interventions specifically aimed to eliminate reactive oxygen species (ROS) and facilitate the repair of MI. We further combined them with a thermosensitive chitosan (CS) hydrogel to construct an injectable composite hydrogel (EGCG@MPDA/CS hydrogel). Utilizing in vitro experiments, the EGCG@MPDA/CS hydrogel exhibited excellent ROS-scavenging ability of H9C2 cells under the oxidative stress environment and also could inhibit their apoptosis. The EGCG@MPDA/CS hydrogel significantly promoted left ventricular ejection fraction (LVEF) in infarcted rat models post injection for 28 days compared to the PBS group (51.25 ± 1.73% vs 29.31 ± 0.78%, P < 0.05). In comparison to the PBS group, histological analysis revealed a substantial increase in left ventricular (LV) wall thickness in the EGCG@MPDA/CS hydrogel group (from 0.58 ± 0.03 to 1.39 ± 1.11 mm, P < 0.05). This work presents a novel approach to enhance MI repair by employing the EGCG@MPDA/CS hydrogel. This hydrogel effectively reduces local oxidative stress by ROS and stimulates the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.

Living photosynthetic microneedle patches for in situ oxygenation and postsurgical melanoma therapy

Surgical excision remains the principal treatment for melanoma, while tumor recurrence and delayed wound healing often occur due to the residual tumor cells and hypoxic microenvironment in the postoperative skin wounds. Herein, we present a living photosynthetic microneedle (MN) patch (namely MA/CM@MN) loaded with microalgae (MA) and cuttlefish melanin (CM) for postsurgical melanoma therapy and skin wound healing. Benefiting from the oxygenic photosynthesis of the alive MA in the MN base, the MA/CM@MN can generate oxygen under light exposure, thus facilitating skin cell proliferation and protecting cells against hypoxia-induced cell death. In addition, with CM nanoparticles embedded in the MN tips, the MA/CM@MN can be effectively heated up under near-infrared (NIR) irradiation, contributing to a strong tumor killing efficacy on melanoma cells in vitro. Further experiments demonstrate that the NIR-irradiated MA/CM@MN effectively prevents local tumor recurrence and simultaneously promotes the healing of tumor-induced wounds after incomplete tumor resection in melanoma-bearing mice, probably because the MA/CM@MN can inhibit tumor cell proliferation, stimulate tumor cell apoptosis, and mitigate tissue hypoxia in light. These results indicate that the living photosynthetic MN patch offers an effective therapeutic strategy for postoperative cancer therapy and wound healing applications.

Controlled release of mesenchymal stem cell-derived nanovesicles through glucose- and reactive oxygen species-responsive hydrogels accelerates diabetic wound healing

Wound healing is often impaired in patients with diabetes. Mesenchymal stem cells (MSCs) and MSCs-derived nanovesicles (MNVs) hold promise as therapeutic agents for managing diabetic wounds. However, efficient delivery and controlled release of MNVs within these wounds are essential for maximizing therapeutic effectiveness. In this study, we developed a dual-responsive hydrogel designed to respond to elevated levels of glucose and reactive oxygen species. This hydrogel combines polyvinyl alcohol with phenylboronic acid-grafted chitosan, referred to as PBA-CP, while MNVs were produced by shearing MSCs through membranes with varying pore sizes. The composite PBA-CP/MNVs hydrogel significantly accelerated wound healing in a diabetic wound model by promoting epithelialization, dermal reconstruction, hair follicle formation, and angiogenesis. MNVs were readily taken up by keratinocytes, fibroblasts, and endothelial cells, stimulating their proliferation and migration. Altogether, the chitosan-based PBA-CP/MNVs composite hydrogel presents a promising therapeutic strategy for diabetic wound treatment.

Polydopamine Nanoformulations Induced ICD and M1 Phenotype Macrophage Polarization for Enhanced TNBC Synergistic Photothermal Immunotherapy

Photothermal therapy (PTT) is a promising technology that can achieve the thermal ablation of tumors and induce immunogenic cell death (ICD). However, relying solely on the antitumor immune responses caused by PTT-induced ICD is insufficient to suppress tumor metastasis and recurrence effectively. Fortunately, multifunctional nanoformulation-based synergistic photothermal immunotherapy can eliminate primary and metastatic tumors and inhibit tumor recurrence for a long time. Herein, we select polydopamine (PDA) nanoparticles to serve as the carrier for our nanomedicine as well as a potent photothermal agent and modulator of macrophage polarization. PDA nanoparticles are loaded with the insoluble immune adjuvant Imiquimod (R837) to construct PDA(R837) nanoformulations. These straightforward yet highly effective nanoformulations demonstrate excellent performance, allowing for successful triple-negative breast cancer (TNBC) treatment through synergistic photothermal immunotherapy. Moreover, experimental results showed that PDA(R837) implementation of PTT is effective in the thermal ablation of primary tumors while causing ICD and releasing R837, further promoting dendritic cell (DC) maturation and activating the systemic antitumor immune response. Furthermore, PDA(R837) nanoformulations inhibit tumor metastasis and recurrence and achieve M1 phenotype macrophage polarization, achieving long-term and excellent antitumor efficacy. Therefore, the structurally simple PDA(R837) nanoformulations provide cancer treatment and have excellent clinical translational application prospects.

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.

Microneedle-Delivered PDA@Exo for Multifaceted Osteoarthritis Treatment via PI3K-Akt-mTOR Pathway

Osteoarthritis (OA) is marked by cartilage deterioration, subchondral bone changes, and an inflammatory microenvironment. The study introduces the Microneedle-Delivered Polydopamine-Exosome (PDA@Exo MN), a therapeutic that not only preserves cartilage and promotes bone regeneration but also improves localized drug delivery through enhanced penetration capabilities. PDA@Exo MN shows strong reactive oxygen species (ROS) scavenging abilities and high biocompatibility, fostering osteogenesis and balancing anabolic and catabolic processes in cartilage. It directs macrophage polarization from M0 to the anti-inflammatory M2 phenotype. RNA sequencing of treated chondrocytes demonstrates restored cellular function and activated antioxidant responses, with modulated inflammatory pathways. The PI3K-AKT-mTOR pathway's activation, essential for PDA@Exo's effects, is confirmed via bioinformatics and Western blot. In vivo assessments robustly validate that PDA@Exo MN prevents cartilage degradation and OA progression, supported by histological assessments and micro-CT analysis, highlighting its disease-modifying impact. The excellent biocompatibility of PDA@Exo MN, verified through histological (H&E) and blood tests showing no organ damage, underscores its safety and efficacy for OA therapy, making it a novel and multifunctional nanomedical approach in orthopedics, characterized by organ-friendliness and biosecurity.

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.

Designing injectable dermal matrix hydrogel combined with silver nanoparticles for methicillin-resistant Staphylococcus aureus infected wounds healing

Hydrogel-based delivery systems have now emerged as a pivotal platform for addressing chronic tissue defects, leveraging their innate capacity to suppress pathogenic infections and facilitate expedited tissue regeneration. In this work, an injectable hydrogel dressing, termed AgNPs-dermal matrix hydrogel (Ag@ADMH), has been designed to expedite the healing process of wounds afflicted with methicillin-resistant Staphylococcus aureus (MRSA), featuring sustained antibacterial efficacy. The synthesis of the hydrogel dressing entailed a self-assembly process of collagen fibers within an acellular dermal matrix to construct a three-dimensional scaffold, encapsulated with plant polyphenol-functionalized silver nanoparticles (AgNPs). The Ag@ADMH demonstrated exceptional biocompatibility, and enables a sustained release of AgNPs, ensuring prolonged antimicrobial activity. Moreover, the in vitro RT-qPCR analysis revealed that compared with ADMH, Ag@ADMH diminish the expression of iNOS while augmenting CD206 expression, thereby mitigating the inflammatory response and fostering wound healing. Especially, the Ag@ADMH facilitated a reduction in M1 macrophage polarization, as evidenced by a significant decrement in the M1 polarization trend and an enhanced M2/M1 ratio in dermal matrix hydrogels laden with AgNPs, corroborated by confocal microscopy and flow cytometry analyses of macrophage phenotypes. The in vivo assessments indicated that Ag@ADMH minimized fibrous capsule formation. In a full-thickness skin defect model of MRSA infection, the formulation significantly attenuated the inflammatory response by reducing MPO and CD68 expression levels, concurrently promoting collagen synthesis and CD34 expression, pivotal for vasculogenesis, thereby accelerating the resolution of MRSA-infected wounds. These attributes underscore the injectable extracellular matrix hydrogel as a formidable strategy for the remediation and regeneration of infected wounds.

Multi-responsive sodium hyaluronate/tannic acid hydrogels with ROS scavenging ability promote the healing of diabetic wounds

Oxidative stress caused by excessive reactive oxygen species (ROS) accumulation significantly hinders wound healing in patients with diabetes. Scavenging ROS and reducing inflammation are crucial for rapid healing. In this work, a multi-responsive sodium hyaluronate (HA)/tannic acid (TA) hydrogel was developed based on boronate ester bonds. Sodium hyaluronate with 3-aminophenyl boronic acid modification (HA-APBA) was mixed and crosslinked with TA to form HA-APBA/TA hydrogels. These hydrogels are injectable, self-healing, and biocompatible. The HA-APBA/TA hydrogels could release free TA through the collapse of the structure at low pH, high H2O2 concentration, and high glucose concentration, thus possessing good ROS scavenging ability. In full-thickness skin wounds of db/db mice, the HA-APBA/TA hydrogels promoted wound healing, collagen deposition, and significant angiogenesis. Furthermore, they have been shown to effectively reduce the levels of inflammatory factors in wounds and lower the expression of CD86, a pro-inflammatory macrophage surface marker. This resulted in a more effective transition of wound healing from the inflammatory phase to the proliferative phase. This study provides an optional strategy for alleviating oxidative stress and controlling excessive inflammation, thereby promoting diabetic wound healing.

Polydopamine-coated polycaprolactone/carbon nanotube fibrous scaffolds loaded with basic fibroblast growth factor for wound healing

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Microneedle transdermal drug delivery as a candidate for the treatment of gouty arthritis: Material structure, design strategies and prospects

Gouty arthritis (GA) is caused by monosodium urate (MSU) crystals deposition. GA is difficult to cure because of its complex disease mechanism and the tendency to reoccur. GA patients require long-term uric acid-lowering and anti-inflammatory treatments. In the past ten years, as a painless, convenient and well-tolerated new drug transdermal delivery method, microneedles (MNs) administration has been continuously developed, which can realize various drug release modes to deal with various complex diseases. Compared with the traditional administration methods (oral and injection), MNs are more conducive to the long-term independent treatment of GA patients because of their safe, efficient and controllable drug delivery ability. In this review, the pathological mechanism of GA and common therapeutic drugs for GA are summarized. After that, MNs drug delivery mechanisms were summarized: dissolution release mechanism, swelling release mechanism and channel-assisted release mechanism. According to drug delivery patterns of MNs, the mechanisms and applications of rapid-release MNs, long-acting MNs, intelligent-release MNs and multiple-release MNs were reviewed. Additionally, existing problems and future trends of MNs in the treatment of GA were also discussed. STATEMENT OF SIGNIFICANCE: Gout is an arthritis caused by metabolic disease "hyperuricemia". Epidemiological studies show that the number of gouty patients is increasing rapidly worldwide. Due to the complex disease mechanism and recurrent nature of gout, gouty patients require long-term therapy. However, traditional drug delivery modes (oral and injectable) have poor adherence, low drug utilization, and lack of local localized targeting. They may lead to adverse effects such as rashes and gastrointestinal reactions. As a painless, convenient and well-tolerated new drug transdermal delivery method, microneedles have been continuously developed, which can realize various drug release modes to deal with gouty arthritis. In this review, the material structure, design strategy and future outlook of microneedles for treating gouty arthritis will be reviewed.

Multifunctionally disordered TiO2 nanoneedles prevent periprosthetic infection and enhance osteointegration by killing bacteria and modulating the osteoimmune microenvironment

Rationale: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are effective interventions for end-stage osteoarthritis; however, periprosthetic infection is a devastating complication of arthroplasty. To safely prevent periprosthetic infection and enhance osteointegration, the surface modification strategy was utilized to kill bacteria, modulate the osteoimmune microenvironment, and improve new bone formation. Methods: We used the hydrothermal method to fabricate a bionic insect wing with the disordered titanium dioxide nanoneedle (TNN) coating. The mussel-inspired poly-dopamine (PDA) and antibacterial silver nanoparticles (AgNPs) were coated on TNN, named AgNPs-PDA@TNN, to improve the biocompatibility and long-lasting bactericidal capacity. The physicochemical properties of the engineered specimen were evaluated with SEM, AFM, XPS spectrum, and water contact assay. The biocompatibility, bactericidal ability, and the effects on macrophages and osteogenic differentiation were assessed with RT-qPCR, Western blotting, live/dead staining, immunofluorescent staining, etc. Results: The AgNPs-PDA@TNN were biocompatible with macrophages and exhibited immunomodulatory ability to promote M2 macrophage polarization. In addition, AgNPs-PDA@TNN ameliorated the cytotoxicity caused by AgNPs, promoted cell spreading, and increased osteogenesis and matrix deposition of BMSCs. Furthermore, AgNPs-PDA@TNN exhibited bactericidal ability against E. coli and S. aureus by the bionic nanostructure and coated AgNPs. Various imaging analyses indicated the enhanced bactericidal ability and improved new bone formation by AgNPs-PDA@TNN in vivo. H&E, Gram, and Masson staining, verified the improved bone formation, less inflammation, infection, and fibrosis encapsulation. The immunofluorescence staining confirmed the immunomodulatory ability of AgNPs-PDA@TNN in vivo. Conclusion: The bionic insect wing AgNPs-PDA@TNN coating exhibited bactericidal property, immunomodulatory ability, and enhanced osteointegration. Thus, this multidimensional bionic implant surface holds promise as a novel strategy to prevent periprosthetic infection.

Polymeric Microneedle Drug Delivery Systems: Mechanisms of Treatment, Material Properties, and Clinical Applications-A Comprehensive Review

Our comprehensive review plunges into the cutting-edge advancements of polymeric microneedle drug delivery systems, underscoring their transformative potential in the realm of transdermal drug administration. Our scrutiny centers on the substrate materials pivotal for microneedle construction and the core properties that dictate their efficacy. We delve into the distinctive interplay between microneedles and dermal layers, underscoring the mechanisms by which this synergy enhances drug absorption and precision targeting. Moreover, we examine the acupoint-target organ-ganglion nexus, an innovative strategy that steers drug concentration to specific targets, offering a paradigm for precision medicine. A thorough analysis of the clinical applications of polymeric microneedle systems is presented, highlighting their adaptability and impact across a spectrum of therapeutic domains. This review also accentuates the systems' promise to bolster patient compliance, attributed to their minimally invasive and painless mode of drug delivery. We present forward-looking strategies aimed at optimizing stimulation sites to amplify therapeutic benefits. The anticipation is set for the introduction of superior biocompatible materials with advanced mechanical properties, customizing microneedles to cater to specialized clinical demands. In parallel, we deliberate on safety strategies aimed at boosting drug loading capacities and solidifying the efficacy of microneedle-based therapeutics. In summation, this review accentuates the pivotal role of polymeric microneedle technology in contemporary healthcare, charting a course for future investigative endeavors and developmental strides within this burgeoning field.

Simultaneous Biofilm Disruption, Bacterial Killing, and Inflammation Elimination for Wound Treatment Using Silver Embellished Polydopamine Nanoplatform

Due to the presence of spatial barriers, persistent bacteria, and excessive inflammation in bacteria biofilm-infected wounds, current nanoplatforms cannot effectively address these issues simultaneously during the therapeutic process. Herein, a novel biomimetic photothermal nanoplatform integrating silver and polydopamine nanoparticles (Ag/PDAs) that can damage biofilms, kill bacterial persisters, and reduce inflammation for wound treatment is presented. These findings reveal that Ag/PDAs exhibit a broad-spectrum antimicrobial activity through direct damage to the bacterial membrane structure. Additionally, Ag/PDAs demonstrate a potent photothermal conversion efficiency. When combined with near-infrared (NIR) irradiation, Ag/PDAs effectively disrupt the spatial structure of biofilms and synergistically eradicate the resident bacteria. Furthermore, Ag/PDAs show remarkable anti-inflammatory properties in counteracting bacterium-induced macrophage polarization. The in vivo results confirm that the topical application of Ag/PDAs significantly suppress Staphylococcus aureus biofilm-infected wounds in murine models, concurrently facilitating wound healing. This research provides a promising avenue for the eradication of bacterial biofilms and the treatment of biofilm-infected wounds.

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.

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.

Designing polysaccharide materials for tissue repair and regeneration

Tissue repair and regeneration are critical processes for maintaining the integrity and function of various organs and tissues. Recently, polysaccharide materials and protein materials have garnered interest for use in tissue repair strategies. However, polysaccharides are more stable and unaffected by temperature and pH changes compared to proteins, and some polysaccharides can provide stronger mechanical support, which is particularly important for constructing tissue-engineered scaffolds and wound dressings. This Review provides an in-depth overview of the origins of polysaccharides, the advantages of polysaccharide materials, and processing and design strategies. In addition, the potential of polysaccharide materials for the restoration of tissues such as skin, heart, and nerves is highlighted. Finally, we discuss in depth the challenges that polysaccharide materials still face in tissue repair, such as the stability of the material, regulating mechanical characteristics and deterioration rates under different conditions. To achieve more effective tissue repair and regeneration, future research must focus on further improving the characteristics and functionalities of polysaccharide materials.

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.

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.

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.

Analysis of current trends in angiogenesis research for wound healing: A bibliometric study from 2013 to 2023

Background

Traumatic injuries, surgery, and chronic diseases lead to soft tissue wounds. Stimulating normal wound healing (WH) is important for tissue repair and restoration of homeostasis. Lack of angiogenesis impedes wound healing and is noted in chronic wounds. The goal of this investigation was to thoroughly assess the present state and patterns of investigations on angiogenesis in WH by the use of bibliometric analysis.

Methods

Studies examining angiogenesis and WH were sourced from the database of the Web of Science Core Collection. Only studies that fulfilled the inclusion criteria were chosen for the purpose of investigation. To analyze the publications included in this research, bibliometric and visual analysis techniques were applied utilizing tools like VOSviewer and CiteSpace.

Results

For the analysis, 11,558 papers were considered. The number of publications increased annually from 2013 to 2023. China, the USA, and South Korea were the top nations in this subject, accounting for 41.1 %, 19.4 %, and 5.8 % of published articles, respectively. The author and institution with the greatest number of publications were found to be Chang J and Shanghai Jiao Tong University. PLOS One had the greatest publication count among journals, whereas Biomaterials had the greatest number of citations and was often mentioned in co-citations. Angiogenesis-related biomedical engineering and tissue engineering were the topics that received the most research attention. Recent studies have focused on vascular endothelial growth factor and carboxymethyl chitosan as emerging areas of interest.

Conclusion

In this investigation, we compiled the features of publications and determined the most impactful nations, organizations, writers, periodicals, popular subjects, and patterns concerning the process of angiogenesis in the context of WH.

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.