Bioinspired Adaptable Indwelling Microneedles for Treatment of Diabetic Ulcers

Glucose-regulating hydrogel for immune modulation and angiogenesis through metabolic reprogramming and LARP7-SIRT1 pathway in infected diabetic wounds

In diabetic-infected wounds, the local hyperglycemic state leads to unique pathological characteristics of diabetic ulcers, such as secondary chronic infections, abnormal angiogenesis, oxidative stress, and diabetic peripheral neuropathy. Glucose oxidase (GOx) is an enzyme that catalyzes the breakdown of glucose into hydrogen peroxide and gluconic acid, making it a candidate enzyme for regulating the hyperglycemic microenvironment in diabetic wounds. However, multifunctional hydrogel therapeutic systems built around the glucose-lowering capability of GOx have rarely been reported. Here, we loaded stachydrine and Au-FePS3 nanosheets onto a quaternized chitosan (QC) - oxidized dextran (OD) hydrogel to construct a synergistic QC-OD@AF/S hydrogel therapeutic system. In vitro experiments showed that Au-FePS3 possesses GOx-POD cascade catalytic activity, capable of reducing glucose concentration and decomposing generated hydrogen peroxide into reactive oxygen species (ROS). Concurrently, Au-FePS3 exhibits excellent photothermal performance under 808 nm infrared light, synergistically exerting antibacterial capabilities with ROS and quaternary ammonium groups. Stachydrine has been demonstrated to mediate the metabolic reprogramming of macrophages and alleviate high-glucose-induced oxidative stress and impairment of angiogenesis in HUVECs through the LARP7-SIRT1 pathway. In summary, the QC-OD@AF/S hydrogel demonstrates superior capabilities in antibacterial activity, immune modulation, promotion of angiogenesis, and reduction of local glucose concentration, making it a potential clinical therapy.

An integrated colorimetric biosensing platform containing microneedle patches and aptasensor for histamine monitoring in seafood

Excessive histamine in spoiled seafood poses considerable health hazards to consumers, yet its detection is challenging due to complicated sample preparation and detection methodologies. Herein, an integrated colorimetric platform containing Poly (vinyl alcohol) (PVA)/hyaluronic acid (HA) microneedle patches-assisted extraction and aptasensor-based detection was reported. The developed PVA/HA microneedle patches facilitated on-site histamine extraction from seafood through a two-minute press-and-peel procedure. To enhance detection efficacy, strategies for generating high-affinity aptamers with specific terminal-fixed structures and constructing AuNPs@FeP-chitosan oligosaccharide (COS) nanozyme boosting catalytic efficiency were proposed. Utilizing the aptamer HIS3-T2 in conjunction with the nanozyme, a colorimetric aptasensor was developed. Integrated with the patches, the aptasensor achieved high sensitivity and selectivity, detecting histamine within a range of 2-800 nM with a limit of detection (LOD) of 1.89 nM. Validated on real-world salmon and shrimp samples, this integrated system promises rapid and accurate histamine monitoring, offering great reference for similar applications in food quality control.

Advances in microneedle-based drug delivery system for metabolic diseases: structural considerations, design strategies, and future perspectives

As the prevalence of metabolic diseases such as diabetes and obesity continue to rise, the search for more effective and convenient treatments has become a crucial issue in medical research. Microneedles (MNs), as an innovative drug delivery system, have shown advantages in the treatment of metabolic diseases in recent years. MNs-based drug delivery system, which use MNs to deliver drugs directly to the subcutaneous tissue, improve drug bioavailability and reduce systemic side effects. This review aims to summarize the latest concepts, designs, and types of MNs, and to investigate the materials and manufacturing methods used in their construction. Subsequently, the mechanisms of drug delivery and graded release of MNs and recent research progress are further summarized. This article focuses on the application of MNs in the treatment of common metabolic diseases, with a special emphasis on the progress and optimization of diabetic and anti-obesity MNs. The main challenges and future perspectives in the production and evaluation of MNs, as well as in enhancing treatment efficacy and improving safety, are elucidated.

Dynamic regulation properties of carrageenan hydrogels based on the Hofmeister effect

κ-Carrageenan (KC) hydrogels are processed from a natural polysaccharide with abundant sources, simple preparation, and superior biocompatibility, which are widely used in the food industry and biomedical applications. Due to fixed water content and loose structure, KC hydrogels crosslinked by hydrogen bonding exhibit inflexible and inferior mechanical properties that considerably restrict their application potential. This study presents a comprehensive investigation of the Hofmeister effect for dynamically modulating KC hydrogels, combining multi-scale mechanistic analysis with versatile applications. The mechanical strength of KC hydrogels was reversibly tuned from 0 to 444 kPa and the hydrogel volume swelling ratio was varied from 0.7 to 1.3 times the original volume. Through a series of characterizations and molecular dynamics simulations, we elucidate the underlying mechanisms via three complementary perspectives: aggregation behavior of molecular chains, microstructural anisotropy, and molecular-level hydrogen bonding interactions. The Hofmeister effect confers dynamic shape tunability properties, regulable volume properties, and adjustable mechanical properties on KC hydrogel, positioning it as a potential shape-regulation material and also rendering it a suitable solution sieve and a probe to measure softness and hardness. The exploration of the Hofmeister effect on KC hydrogels establishes a generalizable framework for understanding Hofmeister effects in natural polymer hydrogels while significantly expanding their potential in intelligent materials.

Grancalcin Hydrogel Microneedle Patches Alleviate Sepsis via Modulation of Calcium Signaling to Augment Immune Cell Phagocytosis

Disorders in Ca2+ signaling contribute to many metabolic manifestations of sepsis and are one of the driving forces underlying multiorgan failure. Herein, a compensatory elevation in calcium-binding protein grancalcin (GCA) levels in monocytes and macrophages of patients and mice with sepsis is observed. Gca deletion in myeloid cells displays increased inflammation and organ damage in cecal ligation and puncture-induced sepsis. Mechanistically, GCA enhances the phagocytic function of immune cells by regulating intracellular calcium signaling. A GCA@Acrylate-PEG-NHS/weakly temperature-sensitive gelatin methacrylate (GelMA) microneedle patch (GCA@NHS/GelMA-MNPs) is designed. In vivo experiments demonstrate that this patch establishes a sustained drug release mechanism, boosts the phagocytic capacity of immune cells, and improves sepsis outcomes by restoring Ca2+ signaling homeostasis. These findings suggest that GCA-loaded hydrogel microneedle patches can be a promising new treatment for sepsis.

Mesenchymal Stem Cell-Derived Exosomes Hold Promise in the Treatment of Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) represent one of the most common side effects of diabetes, significantly impacting patients' quality of life and imposing considerable financial burdens on families and society at large. Despite advancements in therapies targeting lower limb revascularization and various medications and dressings, outcomes for patients with severe lesions remain limited. A recent breakthrough in DFU treatment stems from the development of mesenchymal stem cells (MSCs). MSCs have shown promising results in treating various diseases and skin wounds due to their ability for multidirectional differentiation and immunomodulation. Recent studies highlight that MSCs primarily repair tissue through their paracrine activities, with exosomes playing a crucial role as the main biologically active components. These exosomes transport proteins, mRNA, DNA, and other substances, facilitating DFU treatment through immunomodulation, antioxidant effects, angiogenesis promotion, endothelial cell migration and proliferation, and collagen remodeling. Mesenchymal stem cell-derived exosomes (MSC-Exo) not only deliver comparable therapeutic effects to MSCs but also mitigate adverse reactions like immune rejection associated with MSCs transplantation. This article provides an overview of DFU pathophysiology and explores the mechanisms and research progress of MSC-Exo in DFU therapy.

Microneedle-aided nanotherapeutics delivery and nanosensor intervention in advanced tissue regeneration

Microneedles (MNs) have been extensively used as transdermal therapeutics delivery devices since 1998 due to their capacity to penetrate physiological barriers with minimal invasiveness. Recent advances demonstrate the potential of MNs in improving diverse tissue regeneration when integrated with nanometer-sized therapeutics or sensors. This synergistic strategy can enhance drug delivery efficiency and therapeutic outcomes, and enable precise and personalized therapies through real-time monitoring of the repair process. In this review, we discuss how optimized MNs (through adjustments in geometry, material properties, and modular structure), when combined with dimension- and composition-specific nanomaterials, enhance tissue regeneration efficiency. Moreover, integrating stimuli-responsive nanotherapeutics or nanosensors into MNs for spatiotemporal-controlled and targeted drug release, physiotherapy effects, and intelligent monitoring is systematically outlined. Furthermore, we summarize therapeutic applications of nanotherapeutics-MN platforms in various soft and hard tissues, including skin, hair follicles (HF), cornea, joint, tendons, sciatic nerves, spinal cord, periodontium, oral mucosa, myocardium, endometrium, bone and intervertebral discs (IVD). Notably, recent attempts using nanosensor-MN platforms as smart wearable devices for monitoring damaged tissues via interstitial fluid (ISF) extraction and biomarker sensing are analyzed. This review potentially provides tissue regeneration practitioners/researchers with a cross-disciplinary perspective and inspiration.

A gelatin microneedles featuring antibacterial and reactive oxygen species scavenging properties for treating Vibrio vulnificus-infected wounds

Vibrio vulnificus (V. vulnificus) is highly toxic and lethal. Vibrio vulnificus infected wounds are one of the great challenges in the treatment of its associated diseases. Recent studies have found that dissolvable microneedles can effectively promote repair of infected wounds. Therefore, gelatin microneedles (CeO2-CIP MN) doped with cerium dioxide nanoparticles (CeO2 NPs) and ciprofloxacin (CIP) were rationally designed and prepared based on the characteristics of the microenvironment of bacterial infection. The results of in vitro studies showed that CeO2-CIP MN possessed broad-spectrum antimicrobial activity and antioxidant activity. Importantly, in the seawater-immersed V. vulnificus infected wound model, CeO2-CIP MN effectively killed V. vulnificus, scavenged wound reactive oxygen species (ROS), and promoted cell migration, which subsequently accelerated the repair of the infected wound. In conclusion, this study demonstrated that CeO2-CIP MN can effectively promote the repair of V. vulnificus infected wounds, and also provide ideas for innovative treatment modalities for marine-related diseases.

Accelerating Interface NIR-Induced Charge Transfer Through Cu and Black Phosphorus Modifying G-C3N4 for Rapid Healing of Staphylococcus aureus Infected Diabetic Ulcer Wounds

Bacteria-infected diabetic wounds seriously threaten the lives of patients because diabetic ulcer tissues are quite difficult to repair while the bacteria infections deteriorate this course. Clinically used antibiotics cannot fulfil this mission but introduce the risk of bacterial resistance simultaneously. Herein, a near-infrared (NIR) light-responsive composite hydrogel is developed for rapid bacterial eradication and healing of Staphylococcus aureus (S. aureus)-infected diabetic wounds. The hydrogel incorporates copper (Cu)-doped graphitic carbon nitride (g-C3N4) nanosheets combined with black phosphorus (BP) nanosheets through electrostatic bonding and π-π stacking interactions, uniformly dispersed within a chitosan (CS) matrix crosslinked with polyvinyl alcohol (PVA) (Cu-CN/BP@Gel). Under NIR light irradiation, Cu-doping accelerated hot electron flow and improved the photothermal effect. Additionally, the built-in electric field formed by Cu-CN/BP accelerated interfacial electron flow and inhibited the recombination of electron-hole pairs, enhancing reactive oxygen species (ROS) generation. Then, Cu-CN/BP@Gel hydrogel can reach the antibacterial rate of 99.18% against S. aureus. The successful application of the Cu-CN/BP@Gel hydrogel in diabetic wound infection presents a new method for wound healing in a high blood sugar and ROS environment.

Kinsenoside-Loaded Microneedle Accelerates Diabetic Wound Healing by Reprogramming Macrophage Metabolism via Inhibiting IRE1α/XBP1 Signaling Axis

Continuously bacterial infection, undue oxidative stress, and inflammatory responses in the skin tissue microenvironment determine the delayed healing outcome of diabetic wounds, which remain a tough clinical challenge and need multifaceted therapeutic strategies. In this work, HA-ADH/HA-QA-ALD-based hydrogel microneedle (HAQA-MN) with antimicrobial and antioxidative activities incorporating kinsenoside (KD) coated with macrophage membrane (M-KD) targeting inflammation relief is developed to improve the cutaneous micro-niche. KD is observed to trigger trimethylamine N-oxide-irritated proinflammatory macrophages repolarization from M1 state to anti-inflammatory M2 phenotype, and the underlying mechanism is due to drug-induced IRE1α/XBP1/HIF-1α pathway suppression, accompanied by diminution of glycolysis and enhancement of oxidative phosphorylation, resulting in proinflammatory cascade inhibition and anti-inflammatory signaling enhancement. The hydrazone cross-linked HAQA-MN possesses favorable biocompatibility, self-healing, controlled release of M-KD and excellent mechanical properties. Moreover, the MN patch remarkedly restrains the survival of E. coli and S. aureus and eliminates hydrogen peroxide to preserve cellular viability. Notably, M-KD@HAQA-MN array effectively ameliorates cutaneous inflammation and oxidative stress and facilitate angiogenesis and collagen deposition, thereby accelerating tissue regeneration of diabetic mice with a full-thickness skin defect model. Collectively, this study highlights a multifunctional MN platform as a promising candidate in clinical application for the treatment of diabetic wounds.

Freeze-Derived Anisotropic Porous Microparticles for Engineered Mesenchymal Stem Cell Loading and Wound Healing

Hydrogel microparticles that can effectively deliver mesenchymal stem cells (MSCs) are expected to accelerate wound repair progress. Attempts in the area are focusing on improving the functions of the microparticles and MSCs to promote the therapeutic effect. Here, inspired by the topological morphology of ice branches, we propose novel freeze-derived anisotropic porous microparticles for hepatocyte growth factor (HGF)-overexpressing MSCs (MSCsHGF) loading and wound healing. The microparticles were fabricated by introducing microfluidic methacrylated gelatin pre-gel droplets into low-temperature silicone oil, followed by photo-cross-linking and freeze-drying processes. Drawing an advantage from the biocompatible chemical composition and the structured pore arrangement of the microparticles, MSCsHGF can be efficiently encapsulated and released, maintaining continuous HGF secretion to enhance cell migration and support vascular regeneration. Leveraging these characteristics, we have shown that MSCsHGF-loaded porous microparticles could substantially promote angiogenesis, polarize macrophages toward the M2 phenotype, and reduce inflammation during the wound repair process, consequently enhancing skin wound repair efficiency. Thus, we believe that our MSCsHGF-integrated freeze-derived anisotropic porous microparticles hold promising prospects for clinical wound-healing applications.

Enhancing melanoma therapy with hydrogel microneedles

Melanoma is highly invasive and resistant to conventional treatments, accounting for nearly 75% of skin cancer-related deaths globally. Traditional therapies, such as chemotherapy and immunotherapy, often exhibit limited efficacy and are associated with significant side effects due to systemic drug exposure. Microneedles (MNs), as an emerging drug delivery system, offer multiple advantages, including safety, painlessness, minimal invasiveness, and controlled drug release. Among these, hydrogel microneedles (HMNs) stand out due to their extracellular matrix-like structure and swelling-induced continuous hydrogel channels, which enable the direct delivery of therapeutic agents into the tumor microenvironment (TME). This approach enhances drug bioavailability while reducing systemic toxicity, establishing HMNs as a promising platform for melanoma treatment. This review highlights recent advancements in HMNs for melanoma therapy, focusing on their applications in biomarker extraction for early diagnosis and their role in supporting multimodal treatment strategies, such as chemotherapy, immunotherapy, phototherapy, targeted therapy, and combination therapy. Furthermore, the current matrix materials and fabrication techniques for HMNs are discussed. Finally, the limitations of HMNs in melanoma treatment are critically analyzed, and recommendations for future research and development are provided.

Effervescent Microneedles for the Codelivery of Chitosan Nanoparticles and Indocyanine Green To Enhance the Treatment of Diet-Induced Obesity in Mice

Obesity is a major global health challenge, significantly elevating the risk of cardiovascular disease and type II diabetes. In this study, we identified that self-assembled stearic-acid-modified chitosan oligosaccharide (COA) nanoparticles can efficiently degrade lipid droplets in adipocytes via autolysosomal pathways. By integrating COA nanoparticles with photothermal therapy (PTT), we developed a combination therapy delivered through an effervescent microneedle (MN) patch for treating diet-induced obesity in mice. The effervescent MN patch demonstrated superior skin penetration due to the efficient separation of the needle tips from the backing layer. Over a four-week treatment period, the COA nanoparticle and indocyanine green coloaded MN patches dramatically reduced body weight and white adipose tissue in obese mice without affecting their food intake. Histological analysis further revealed a reduced lipid droplet size and increased expression of UCP-1 within adipose tissues in vivo. Additionally, the combination therapy improved glucose metabolism and insulin sensitivity in obese mice. These findings suggest that COA nanoparticles delivered via an MN patch, when combined with localized PTT, effectively combat obesity and its associated metabolic complications in an obese mouse model. This approach presents a promising alternative to oral and injectable weight loss medications, offering improved efficacy with fewer side effects.

Nature-derived microneedles with metal-polyphenolic networks encapsulation for chronic soft tissue defects repair: Responding and remodeling the regenerative microenvironment

The treatment outcomes of traditional patches for chronic soft tissue defects (CSTDs) are unsatisfactory in clinical, owing to the lack of intrinsic bioactivities to orchestrate the intricate regenerative process. To tackle this deficiency, nature-derived microneedles (NMs) composed of silk methacrylate and snail mucus are developed in this study. The resultant NMs have excellent mechanical strength and biological adhesiveness, ensuring suture-free but reliable fixation on implanted site. To enhance the intrinsic bioactivities, metal-polyphenolic networks (MPNs) coordinated from copper (Cu) and curcumin (Cur) are designed and encapsulated into NMs. Cu-Cur MPNs harness the anti-oxidative and anti-inflammatory properties of Cur with the pro-angiogenic properties of Cu, targeting different negative aspects in CSTDs repair. Furthermore, the pH-responsive disassembly of Cu-Cur MPNs can respond to the acidic microenvironment, allowing for burst-free and on-demand drug delivery. Both in-vitro and in-vivo experiments demonstrate that NMs with Cu-Cur MPNs encapsulation (Cu-Cur-NMs) can restore redox homeostasis, reduce inflammatory response, and promote blood vessel formation, thus remodeling the regenerative microenvironment to greatly improve the repair quality of CSTDs. Therefore, the combined advantages of microneedles-based patch system and MPNs-based nanotherapeutic agent are explored for the first time, and our proposed Cu-Cur-NMs represent a multifunctional and promising device for CSTDs repair.

Dual-layer microneedles with NO/O2 releasing for diabetic wound healing via neurogenesis, angiogenesis, and immune modulation

Diabetic wounds present multiple functional impairments, including neurovascular dysregulation, oxidative imbalance, and immune dysfunction, making wound healing particularly challenging, while traditional therapeutical strategies fail to address these complex issues effectively. Herein, we propose a strategy utilizing dual-layer microneedles to deliver therapeutic gases by modulating neurovascular coupling and immune functions for diabetic wound treatment. The microneedle can respond to reactive oxygen species (ROS) in the diabetic microenvironment and subsequently generate oxygen (O2) and nitric oxide (NO). These gases comprehensively promote neuro-vascular regeneration, reduce oxidative stress levels, and attenuate inflammation. In vivo studies demonstrate that the microneedle can accelerate diabetic wound healing by modulating neurovascular regeneration and inflammatory processes. Transcriptomic analyses further validate the involvement of related advantageous signaling pathways. The potential mechanism involves the activation of the PI3K-AKT-mTOR pathway to facilitate autophagy, ultimately accelerating the healing process. Thus, our multifunctional dual-layer microneedles provide an effective strategy for treating diabetic wounds.

Recent advances in microneedles for enhanced functional angiogenesis and vascular drug delivery

Many therapeutic applications use the transdermal method to avoid the severe restrictions associated with oral medication delivery. Given the limitations of traditional drug delivery via skin, transdermal microneedle (MN) arrays have been reported to be versatile and very efficient devices due to their outstanding characteristics such as painless penetration, affordability, excellent medicinal efficacy, and relative safety. MNs have recently received increased attention for their ability to cure vascular illnesses such as hypertension and thrombosis, as well as promote wound healing via the angiogenesis impact. The integrant of method manufacturing and biodegradable material allows for the modification of MN form and drug release pattern, hence increasing the flexibility of such drug delivery. In this review, we focused on recent improvements in MN-mediated transdermal administration of protein and peptide medicines for improved functional angiogenesis and vascular therapy. We also provide an overview of the present applications of MNs-mediated transdermal protein and peptide administration, particularly in the realm of vascular system disease therapy. Finally, the current state of clinical translation and a forecast for future progress are provided.

A Scoping Review of Exosome Delivery Applications in Hair Loss

The objective of this scoping review was to understand the extent and type of evidence found in the current literature on the delivery mechanisms of exosome therapeutics and how these methods can work synergistically with existing treatments for alopecia. Alopecia is primarily characterized as non-scarring or scarring (cicatricial). In cicatricial alopecia, the hair follicles are irreversibly destroyed, causing permanent hair loss. In non-cicatricial alopecia, the hair follicles are undamaged, allowing for possible hair regeneration. Non-scarring alopecia includes androgenetic alopecia, telogen effluvium, and alopecia areata. Current treatments for non-scarring alopecia include oral minoxidil and spironolactone. Exosome therapeutics are a possible alternative treatment for non-scarring alopecia because of their regenerative properties in hair follicle stimulation, customizable size selection, and the potential to activate and down-regulate specific pathways that enhance hair growth. This review evaluates types and sources of exosome delivery as regenerative treatments for alopecia. A search of literature published in English from 2018 to 2023 was performed using the electronic databases EMBASE, Ovid MEDLINE, and Web of Science. Data from selected studies included specific details about the participants, concept, context, study methods, and key findings relevant to the review questions. Upon completion of the database search that yielded 1,087 citations, after removing 284 duplicates, 803 articles remained for assessment of eligibility. Finally, 16 studies were retained for inclusion. These studies explored one or more exosome delivery techniques, such as intradermal needle injection, microneedle patches, topical application, and topical application with a secondary assistive device. The therapeutic focus of these studies ranged from hair follicle regeneration and wound healing to spinal cord injury repair and collagen regeneration for cosmetic purposes. Most of the studies (14 out of 16) used exosomes derived from mesenchymal stem cells (MSCs), while others isolated exosomes from human adipose stem cells, macrophage cell lines, and dermal fibroblast cells. Of the 16 studies, all but two administered exosomes via microneedle patches. The findings suggest that intradermal microneedle patches are a promising method for delivering exosomes into tissues, particularly for the treatment of non-cicatricial alopecia. Exosome therapy shows strong potential for promoting hair follicle regeneration, supported by its proven efficacy in wound healing, spinal cord injury repair, and cosmetic applications. Among the various delivery methods explored, microneedle patches loaded with exosomes from MSCs emerged as the most effective for targeted delivery into tissues. These findings support exosome-based therapies for non-cicatricial alopecia.

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.

Dedifferentiated fat cells-derived exosomes (DFATs-Exos) loaded in GelMA accelerated diabetic wound healing through Wnt/β-catenin pathway

BACKGROUND

Diabetic foot ulcers pose significant challenges for clinicians worldwide. Cell-free exosome therapy holds great potential for wound healing. Dedifferentiated fat cells (DFATs) have been used in tissue engineering and regeneration, but there are no reports on the use of DFATs-derived exosomes in diabetic wound repair.

OBJECTIVES

This study aims to investigate whether DFATs-Exos accelerated diabetic wound healing and explore its potential mechanism.

METHODS

In vitro, DFATs-Exos were harvested from adipose tissue and used to treat endothelial cells (ECs) and fibroblasts. XAV939 was used as a Wnt/β-catenin pathway inhibitor. The biocompatibility of gelatin methacryloyl (GelMA) hydrogel was assessed. In vivo, DFAT-derived exosomes were encapsulated in 10% GelMA hydrogel and applied to a diabetic wound model. Histological analysis and wound closure rates were evaluated.

RESULTS

DFATs-Exos promoted angiogenesis in ECs and significantly alleviated the high glucose-induced inhibition of cell proliferation and migration by activating the Wnt/β-catenin pathway. In vivo, compared to DFAT-Exos or GelMA alone, the DFAT-Exos/GelMA combination accelerated wound closure and enhanced collagen maturity.

CONCLUSION

The DFAT-Exos/GelMA hydrogel significantly promoted wound healing in a diabetic animal model through activation of the Wnt/β-catenin signaling pathway.

Advances of exosomes in diabetic wound healing

Poor wound healing is a refractory process that places an enormous medical and financial burden on diabetic patients. Exosomes have recently been recognized as crucial players in the healing of diabetic lesions. They have excellent stability, homing effects, biocompatibility, and reduced immunogenicity as novel cell-free therapies. In addition to transporting cargos to target cells to enhance intercellular communication, exosomes are beneficial in nearly every phase of diabetic wound healing. They participate in modulating the inflammatory response, accelerating proliferation and reepithelization, increasing angiogenesis, and regulating extracellular matrix remodeling. Accumulating evidence indicates that hydrogels or dressings in conjunction with exosomes can prolong the duration of exosome residency in diabetic wounds. This review provides an overview of the mechanisms, delivery, clinical application, engineering, and existing challenges of the use of exosomes in diabetic wound repair. We also propose future directions for biomaterials incorporating exosomes: 2D or 3D scaffolds, biomaterials loaded with wound healing-promoting gases, intelligent biomaterials, and the prospect of systematic application of exosomes. These findings may might shed light on future treatments and enlighten some studies to improve quality of life among diabetes patients.

Microneedles in diabetic wound care: multifunctional solutions for enhanced healing

Diabetic wounds present a significant challenge in clinical treatment and are characterized by chronic inflammation, oxidative stress, impaired angiogenesis, peripheral neuropathy, and a heightened risk of infection during the healing process. By creating small channels in the surface of the skin, microneedle technology offers a minimally invasive and efficient approach for drug delivery and treatment. This article begins by outlining the biological foundation of normal skin wound healing and the unique pathophysiological mechanisms of diabetic wounds. It then delves into the various types, materials, and preparation processes of microneedles. The focus is on the application of multifunctional microneedles in diabetic wound treatment, highlighting their antibacterial, anti-inflammatory, immunomodulatory, antioxidant, angiogenic and neural repair properties. These multifunctional microneedles demonstrate synergistic therapeutic effects by directly influencing the wound microenvironment, ultimately accelerating the healing of diabetic wounds. The advancement of microneedle technology not only holds promise for enhancing the treatment outcomes of diabetic wounds but also offers new strategies for addressing other chronic wounds.

Extracellular Matrix-Inspired Dendrimer Nanogels Encapsulating Cyclophosphamide for Systemic Sclerosis Treatment

Cyclophosphamide has a certain therapeutic effect on treating systemic sclerosis (SSc), while difficulties exist in controlling severe systematic side effects and enhancing targeting capacity. Here, inspired from the natural extracellular matrix composition, we propose a cyclophosphamide-encapsulated nanogel based on dendritic polymers polyamidoamine (PAMAM) for SSc treatment. We combine bovine serum albumin and generation 5 (G5) PAMAM dendrimers with polyphenol modification to obtain nanogels featured with antioxidant and anti-inflammatory effects. The nanogels can possess excellent biocompatibility and prevent fibroblasts from oxidative stress damage and TGF-β-mediated activation. Furthermore, in the bleomycin-induced SSc mouse model, dendrimer nanogels encapsulating cyclophosphamide also exhibit the ability to attenuate fibrosis by modulating immunity, suppressing inflammation, and reducing collagen synthesis. These findings underscore the value of this dendritic polymer nanogel in the treatment of chronic SSc, indicating its broader potential for clinical applications.

Glucose oxidase: An emerging multidimensional treatment option for diabetic wound healing

The healing of diabetic skin wounds is a complex process significantly affected by the hyperglycemic environment. In this context, glucose oxidase (GOx), by catalyzing glucose to produce gluconic acid and hydrogen peroxide, not only modulates the hyperglycemic microenvironment but also possesses antibacterial and oxygen-supplying functions, thereby demonstrating immense potential in the treatment of diabetic wounds. Despite the growing interest in GOx-based therapeutic strategies in recent years, a systematic summary and review of these efforts have been lacking. To address this gap, this review article outlines the advancements in the application of GOx and GOx-like nanozymes in the treatment of diabetic wounds, including reaction mechanisms, the selection of carrier materials, and synergistic therapeutic strategies such as multi-enzyme combinations, microneedle structures, and gas therapy. Finally, the article looks forward to the application prospects of GOx in aiding the healing of diabetic wounds and the challenges faced in translating these innovations to clinical practice. We sincerely hope that this review can provide readers with a comprehensive understanding of GOx-based diabetic treatment strategies, facilitate the rigorous construction of more robust multifunctional therapeutic systems, and ultimately benefit patients with diabetic 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.

Toward precision medicine: End-to-end design and construction of integrated microneedle-based theranostic systems

With the growing demand for precision medicine and advancements in microneedle technology, microneedle-based drug delivery systems have evolved into integrated theranostic platforms. However, the development of these systems is currently limited by the absence of clear conclusions and standardized construction strategies. The end-to-end concept offers an innovative approach to theranostic systems by creating a seamless process that integrates target sampling, sensing, analysis, and on-demand drug delivery. This approach optimizes each step based on data from the others, effectively eliminating the traditional separation between drug delivery and disease monitoring. Furthermore, by incorporating artificial intelligence and machine learning, these systems can enhance reliability and efficiency in disease management, paving the way for more personalized and effective healthcare solutions. Based on the concept of end-to-end and recent advancements in theranostic systems, nanomaterials, electronic components, micro-composites, and data science, we propose a modular strategy for constructing integrated microneedle-based theranostic systems by detailing the methods and functions of each critical component, including monitoring, decision-making, and on-demand drug delivery units, though the total number of units might vary depending on the specific application. Notably, decision-making units are emerging trends for fully automatic and seamless systems and featured for integrated microneedle-based theranostic systems, which serve as a bridge of real-time monitoring, on-demand drug delivery, advanced electronic engineering, and data science for personalized disease management and remote medical application. Additionally, we discuss the challenges and prospects of integrated microneedle-based theranostic systems for precision medicine and clinical application.

From Sequence to System: Enhancing IVT mRNA Vaccine Effectiveness through Cutting-Edge Technologies

The COVID-19 pandemic has spotlighted the potential of in vitro transcribed (IVT) mRNA vaccines with their demonstrated efficacy, safety, cost-effectiveness, and rapid manufacturing. Numerous IVT mRNA vaccines are now under clinical trials for a range of targets, including infectious diseases, cancers, and genetic disorders. Despite their promise, IVT mRNA vaccines face hurdles such as limited expression levels, nonspecific targeting beyond the liver, rapid degradation, and unintended immune activation. Overcoming these challenges is crucial to harnessing the full therapeutic potential of IVT mRNA vaccines for global health advancement. This review provides a comprehensive overview of the latest research progress and optimization strategies for IVT mRNA molecules and delivery systems, including the application of artificial intelligence (AI) models and deep learning techniques for IVT mRNA structure optimization and mRNA delivery formulation design. We also discuss recent development of the delivery platforms, such as lipid nanoparticles (LNPs), polymers, and exosomes, which aim to address challenges related to IVT mRNA protection, cellular uptake, and targeted delivery. Lastly, we offer insights into future directions for improving IVT mRNA vaccines, with the hope to spur further progress in IVT mRNA vaccine research and development.

Advances in Research of Hydrogel Microneedle-Based Delivery Systems for Disease Treatment

Microneedles (MNs), composed of multiple micron-scale needle-like structures attached to a base, offer a minimally invasive approach for transdermal drug delivery by penetrating the stratum corneum and delivering therapeutic agents directly to the epidermis or dermis. Hydrogel microneedles (HMNs) stand out among various MN types due to their excellent biocompatibility, high drug-loading capacity, and tunable drug-release properties. This review systematically examines the matrix materials and fabrication methods of HMN systems, highlighting advancements in natural and synthetic polymers, and explores their applications in treating conditions such as wound healing, hair loss, cardiovascular diseases, and cancer. Furthermore, the potential of HMNs for disease diagnostics is discussed. The review identifies key challenges, including limited mechanical strength, drug-loading efficiency, and lack of standardization, while proposing strategies to overcome these issues. With the integration of intelligent design and enhanced control over drug dosage and safety, HMNs are poised to revolutionize transdermal drug delivery and expand their applications in personalized medicine.

Smart drug delivery and responsive microneedles for wound healing

Wound healing is an ongoing concern for the medical community. The limitations of traditional dressings are being addressed by materials and manufacturing technology. Microneedles (MNs) are a novel type of drug delivery system that has been widely used in cancer therapy, dermatological treatment, and insulin and vaccine delivery. MNs locally penetrate necrotic tissue, eschar, biofilm and epidermis into deep tissues, avoiding the possibility of drug dilution and degradation and greatly improving administration efficiency with less pain. MNs represent a new direction for wound treatment and transdermal delivery. In this study, we summarise the skin wound healing process and the mechanical stimulation of MNs in the context of the wound healing process. We also introduce the structural design and manufacture of MNs. Subsequently, MNs are categorised according to the loaded drugs, where the design of the MNs according to the traumatic biological/biochemical microenvironment (pH, glucose, and bacteria) and the physical microenvironment (temperature, light, and ultrasound) is emphasised. Finally, the advantages of MNs are compared with traditional drug delivery systems and their prospects are discussed.

Composite microneedles loaded with Astragalus membranaceus polysaccharide nanoparticles promote wound healing by curbing the ROS/NF-κB pathway to regulate macrophage polarization

The healing of chronic diabetic wounds remains a formidable challenge in modern times. In this study, a novel traditional Chinese medicine microneedle patch was designed based on the physiological characteristics of wounds, with properties including hemostasis, anti-inflammatory, antioxidant, antimicrobial, and induction of angiogenesis. Initially, white peony polysaccharide (BSP) with hemostatic properties and carboxymethyl chitosan (CMCS) with antimicrobial capabilities were used as materials for microneedle fabrication. To endow it with antimicrobial, procoagulant, and adhesive properties. Among them, loaded with ROS-sensitive nanoparticles of Astragalus polysaccharides (APS) based on effective components baicalein (Bai) and berberine (Ber) from Scutellaria baicalensis (SB) and Coptis chinensis (CC) drugs (APB@Ber). Together, they are constructed into multifunctional traditional Chinese medicine composite microneedles (C/B@APB@Ber). Bai and Ber synergistically exert anti-inflammatory and antimicrobial effects. Microneedle patches loaded with BSP and APS exhibited significant effects on cell proliferation and angiogenesis induction. The combination of composite polysaccharides enabled the microneedles to adhere stably to wounds and provide sufficient strength to penetrate the biofilm and induce dispersion. The combination of composite polysaccharides enabled the microneedles to adhere stably to wounds and provide sufficient strength to penetrate the biofilm and induce dispersion. Therefore, traditional Chinese medicine multifunctional microneedle patches offer potential medical value in promoting the healing of diabetic wounds.

3D Printing-Based Hydrogel Dressings for Wound Healing

Skin wounds have become an important issue that affects human health and burdens global medical care. Hydrogel materials similar to the natural extracellular matrix (ECM) are one of the best candidates for ideal wound dressings and the most feasible choices for printing inks. Distinct from hydrogels made by traditional technologies, which lack bionic and mechanical properties, 3D printing can promptly and accurately create hydrogels with complex bioactive structures and the potential to promote tissue regeneration and wound healing. Herein, a comprehensive review of multi-functional 3D printing-based hydrogel dressings for wound healing is presented. The review first summarizes the 3D printing techniques for wound hydrogel dressings, including photo-curing, extrusion, inkjet, and laser-assisted 3D printing. Then, the properties and design approaches of a series of bioinks composed of natural, synthetic, and composite polymers for 3D printing wound hydrogel dressings are described. Thereafter, the application of multi-functional 3D printing-based hydrogel dressings in a variety of wound environments is discussed in depth, including hemostasis, anti-inflammation, antibacterial, skin appendage regeneration, intelligent monitoring, and machine learning-assisted therapy. Finally, the challenges and prospects of 3D printing-based hydrogel dressings for wound healing are presented.

Local Release of Copper Manganese Oxide Using HA Microneedle for Improving the Efficacy of Drug-Resistant Wound Inflammation

The production of bacterial toxins and excessive accumulation of reactive oxygen species (ROS) can induce localized oxidative stress, triggering an exaggerated immune response that impedes wound healing and culminates in chronic wounds. To address this issue, a microneedle (MN) system loaded with copper-manganese oxide (CMO) is developed to modulate the hyperimmune response in wounds. CMO@MN exhibits excellent antimicrobial and anti-inflammatory properties by effectively killing bacteria, scavenging ROS, and modulating macrophage polarization through their multiple enzymatic activities and photothermal properties. RNA sequencing revealed that CMO@MN improved the therapeutic effect on the infected skin of mice by balancing the ratio of M1/M2 macrophages and promoting cell migration and angiogenesis through the regulation of relevant pathways. Overall, this CMO@MN patch skillfully balances the complex issues between the immune response and wound healing and has potential applications in the treatment of other serious bacterial infections.

Multifunctional Microneedle Patches for Perivascular Gene Delivery and Treatment of Vascular Intimal Hyperplasia

Gene therapy has emerged as a promising approach to address challenging cardiovascular diseases. Extensive efforts have been focused on developing highly efficient gene vectors with precise delivery techniques to enhance its effectiveness. In this study, we present multifunctional dopamine-gelatin microneedle patches with gene therapy capabilities to achieve perivascular gene delivery for intimal hyperplasia treatment. These patches that were fabricated through freeze-drying of gelatin are with recombinant adeno-associated virus (rAAVs)-carrying tips and dopamine coating backing layers. The lyophilized gelatin could not only effectively preserve the therapeutic activity of rAAVs but could also demonstrate the capability to penetrate the adventitia for efficient delivery. The incorporation of dopamine facilitated patch adhesion and extended the release duration. Based on these advantages, we have demonstrated that the rAAVs-loaded microneedle patches (AMNPs) behave satisfactorily in perivascular gene delivery to inhibit carotid artery restenosis in rats. These features indicate that the AMNPs are clinically valuable in the treatment of vascular intimal hyperplasia diseases.

Photocrosslinkable Biomaterials for 3D Bioprinting: Mechanisms, Recent Advances, and Future Prospects

Constructing scaffolds with the desired structures and functions is one of the main goals of tissue engineering. Three-dimensional (3D) bioprinting is a promising technology that enables the personalized fabrication of devices with regulated biological and mechanical characteristics similar to natural tissues/organs. To date, 3D bioprinting has been widely explored for biomedical applications like tissue engineering, drug delivery, drug screening, and in vitro disease model construction. Among different bioinks, photocrosslinkable bioinks have emerged as a powerful choice for the advanced fabrication of 3D devices, with fast crosslinking speed, high resolution, and great print fidelity. The photocrosslinkable biomaterials used for light-based 3D printing play a pivotal role in the fabrication of functional constructs. Herein, this review outlines the general 3D bioprinting approaches related to photocrosslinkable biomaterials, including extrusion-based printing, inkjet printing, stereolithography printing, and laser-assisted printing. Further, the mechanisms, advantages, and limitations of photopolymerization and photoinitiators are discussed. Next, recent advances in natural and synthetic photocrosslinkable biomaterials used for 3D bioprinting are highlighted. Finally, the challenges and future perspectives of photocrosslinkable bioinks and bioprinting approaches are envisaged.

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.

A biphasic drug-releasing microneedle with ROS scavenging and angiogenesis for the treatment of diabetic ulcers

Diabetic ulcers are one of the common complications in diabetic patients. Delayed wound healing is associated with persistent pro-inflammatory M1 polarization, reduced angiogenesis and increased reactive oxygen species (ROS) in the microenvironment. Wound healing consists of multiple phases and therefore requires treatment tailored to each phase. In this study, a biphasic drug-releasing microneedle (MN) was fabricated to achieve early ROS scavenging and late accelerated angiogenesis to promote wound healing. Vascular endothelial growth factor (VEGF) was first encapsulated in methacryloylated sulfonated chitosan (SCSMA) microspheres (V@MP), and then V@MP was loaded into hyaluronic acid (HA) microneedles along with cerium dioxide nanoparticles (CONPs). Rapid dissolution of HA rapidly releases the CONPs to clear ROS, whereas the V@MP stays in the wound. SCSMA slow degradation prolongs the release of VEGF, thereby promoting angiogenesis. In vitro and in vivo studies have shown that this biphasic drug-releasing smart microneedle improves cell proliferation and migration, effectively scavenges ROS, promotes angiogenesis and tissue regeneration, and synergistically promotes M2 macrophage polarization. It provides a new delivery mode for nano-enzymes and growth factors that could be multifunctional and synergistic in the treatment of diabetic ulcers. STATEMENT OF SIGNIFICANCE: In our study, we present a microneedle (V@MP/C@MN) that can release drugs biphasically, which showed good repair ability in diabetic ulcer model. Large amounts of CONPs were rapidly released to alleviate oxidative stress during the inflammation of the wound, and V@MP stayed in the wound for a long period of time to release VEGF and promote angiogenesis in the late stage of wound healing. The results indicated that V@MP/C@MN could promote cell proliferation and migration, effectively scavenge ROS, promote angiogenesis and tissue regeneration, and synergistically promote M2 macrophage polarization, which could play a multifunctional and synergistic role in the treatment of diabetic ulcers.

Mesoporous Microneedles Enabled Localized Controllable Delivery of Stimulator of Interferon Gene Agonist Nanoexosomes for FLASH Radioimmunotherapy against Breast Cancer

The immunosuppressive nature of the tumor microenvironment (TME) contributes to radioresistance, thereby impairing the effectiveness of radiotherapy as a therapeutic intervention. Activation through the stimulator of interferon genes (STING) pathway shows potential in modulating immunogenicity. However, the therapeutic efficacy of STING agonists might be restricted by off-target effects and potential cytotoxicity. In this work, nanoexosomes (EXOs) loaded within porous microneedles were employed for precise delivery of the STING agonist MSA-2 (MEM) to the tumor site. Leveraging the enhanced tumor penetration enabled by microneedles, EXOs can be continually released and accumulate within deep residual tumors. Once internalized, these EXOs release the encapsulated MSA-2, facilitating the activation of the STING pathway upon exposure to ultrahigh dose-rate (FLASH) irradiation. This strategy elevates the type I interferon level, promotes dendric cell maturation, and modulates the immunosuppressive TME, showing efficient antitumor efficacy in both primary/metastatic tumors. Furthermore, the induction of a potent immune response effectively prevented tumor recurrence. The combination of EXO-loaded microneedles with FLASH radiotherapy resulted in minimal systemic side effects, attributed to precise drug delivery and radioprotection conferred by FLASH. Altogether, the strategic design of EXO-loaded microneedles holds promise for enhancing MSA-2 delivery, thereby mitigating the radioresistant tumor microenvironment through STING cascade activation-mediated immunotherapy, consequently optimizing the outcomes of FLASH radiotherapy.

Silver Nanoclusters-Decorated Porous Microneedles Coupling Duplex-Specific Nuclease-Assisted Signal Amplification for Sampling and Detection of MicroRNA in Interstitial Fluid

MicroRNAs (miRNAs) in dermal interstitial fluid (ISF) have recently been recognized as clinically promising biomarkers for the diagnosis and prognosis of cancer. However, the detection poses significant challenges, primarily due to the low abundance of miRNAs and the limitations of current sampling techniques. To address this issue, we develop novel porous microneedles (PMNs) array-based sensor composed of poly(vinyl alcohol) porous hydrogel and DNA-templated silver nanoclusters (AgNCs) to facilitate the enrichment and highly sensitive detection of ISF miRNA. Leveraging the capillary action facilitated by its unique porous structure and the swelling properties of the hydrogel, the PMNs array can efficiently extract 2.7 ± 0.3 mg of ISF within 5 min. Additionally, the interconnected pores within the PMNs array contribute to an increased specific surface area, thereby offering a convenient platform for the decoration of DNA-templated AgNCs. The immobilized large amount of AgNCs effectively capture the target miRNA from the extracted ISF, resulting in miRNA-induced fluorescence quenching of AgNCs. Subsequently, the introduction of the duplex-specific nuclease leads to the cleavage of DNA in DNA-RNA heteroduplexes, which release miRNA to interact with other AgNCs. This process of target recycling triggers a further reduction in fluorescence intensity, thereby enabling sensitive detection of the low-abundant miRNA down to 1.6 pM. Both in vitro and in vivo experiments validate the efficacy of the AgNCs immobilized PMNs array for the detection of miRNA biomarkers in ISF within minutes. These results indicate that the proposed PMNs array-based sensor holds great potential for the development of noninvasive personalized diagnostic strategies.

Hyaluronic acid dissolving microneedle patch-assisted acupoint transdermal delivery of triptolide for effective rheumatoid arthritis treatment

Triptolide (TP), a major active component of the herb Tripterygium wilfordii Hook F, has been shown excellent pharmacological effects on rheumatoid arthritis. However, TP is prone to causing severe organ toxicity, which limits its clinical application. In recent years, microneedle technology has provided a new option for the treatment of arthritis due to its advantages of efficient local transdermal drug delivery. In this study, we constructed a microneedle platform to deliver TP locally to the joints, thereby enhancing TP penetration and reducing systemic toxicity. Additionally, we investigated whether acupoint drug delivery can produce a synergistic effect of needles and drugs. First, TP was loaded into microneedles using polyvinylpyrrolidone and hyaluronic acid as matrix materials. Next, we established a rat adjuvant-induced arthritis (AIA) model to evaluate the therapeutic effect of TP-loaded microneedles. The experiments showed that TP-loaded microneedles alleviated the AIA rats' inflammatory response, joint swelling, and bone erosion. However, there was no significant difference in the therapeutic effect observed in the acupoint and non-acupoint administration groups. In conclusion, TP-loaded microneedles have the advantages of safety, convenience, and high efficacy over conventional administration routes, laying a foundation for the transdermal drug delivery system-based treatment of rheumatoid arthritis.

Core-Shell Gel Nanofiber Scaffolds Constructed by Microfluidic Spinning toward Wound Repair and Tissue Regeneration

Growing demand for wound care resulting from the increasing chronic diseases and trauma brings intense pressure to global medical health service system. Artificial skin provides mechanical and microenvironmental support for wound, which is crucial in wound healing and tissue regeneration. However, challenges still remain in the clinical application of artificial skin since the lack of the synergy effect of necessary performance. In this study, a multi-functional artificial skin is fabricated through microfluidic spinning technology by using core-shell gel nanofiber scaffolds (NFSs). This strategy can precisely manipulate the microstructure of artificial skin under microscale. The as-prepared artificial skin demonstrates superior characteristics including surface wettability, breathability, high mechanical strength, strain sensitivity, biocompatibility and biodegradability. Notably, this artificial skin has the capability to deliver medications in a controlled and sustained manner, thereby accelerating the wound healing process. This innovative approach paves the way for the development of a new generation of artificial skin and introduces a novel concept for the structural design of the unique core-shell gel NFSs.

Developing functional hydrogels for treatment of oral diseases

Oral disease is a severe healthcare challenge that diminishes people's quality of life. Functional hydrogels with suitable biodegradability, biocompatibility, and tunable mechanical properties have attracted remarkable interest and have been developed for treating oral diseases. In this review, we present up-to-date research on hydrogels for the management of dental caries, endodontics, periapical periodontitis, and periodontitis, depending on the progression of dental diseases. The strategies of hydrogels for treating oral mucosal diseases and salivary gland diseases are then classified. After that, we focus on the application of hydrogels related to tumor therapy and tissue defects. Finally, the review prospects the restrictions and the perspectives on the utilization of hydrogels in oral disease treatment. We believe this review will promote the advancement of more amicable, functional and personalized approaches for oral diseases.

DNA Nanomaterial-Empowered Surface Engineering of Extracellular Vesicles

Extracellular vesicles (EVs) are cell-secreted biological nanoparticles that are critical mediators of intercellular communication. They contain diverse bioactive components, which are promising diagnostic biomarkers and therapeutic agents. Their nanosized membrane-bound structures and innate ability to transport functional cargo across major biological barriers make them promising candidates as drug delivery vehicles. However, the complex biology and heterogeneity of EVs pose significant challenges for their controlled and actionable applications in diagnostics and therapeutics. Recently, DNA molecules with high biocompatibility emerge as excellent functional blocks for surface engineering of EVs. The robust Watson-Crick base pairing of DNA molecules and the resulting programmable DNA nanomaterials provide the EV surface with precise structural customization and adjustable physical and chemical properties, creating unprecedented opportunities for EV biomedical applications. This review focuses on the recent advances in the utilization of programmable DNA to engineer EV surfaces. The biology, function, and biomedical applications of EVs are summarized and the state-of-the-art achievements in EV isolation, analysis, and delivery based on DNA nanomaterials are introduced. Finally, the challenges and new frontiers in EV engineering are discussed.

Circadian Rhythm-Regulated ADSC-Derived sEVs and a Triphasic Microneedle Delivery System to Enhance Tendon-to-Bone Healing

Modulating the inflammatory microenvironment to reconstruct the fibrocartilaginous layer while promoting tendon repair is crucial for enhancing tendon-to-bone healing in rotator cuff repair (RCR), a persistent challenge in orthopedics. Small extracellular vesicles (sEVs) hold significant potential to modulate inflammation, yet the efficient production of highly bioactive sEVs remains a substantial barrier to their clinical application. Moreover, achieving minimally invasive local delivery of sEVs to the tendon-to-bone interface presents significant technical difficulties. Herein, the circadian rhythm of adipose-derived stem cells is modulated to increase the yield and enhance the inflammatory regulatory capacity of sEVs. Circadian rhythm-regulated sEVs (CR-sEVs) enhance the cyclic adenosine monophosphate signaling pathway in macrophage (Mφ) via platelet factor 4 delivery, thereby inhibiting Mφ M1 polarization. Subsequently, a triphasic microneedle (MN) scaffold with a tip, stem, and base is designed for the local delivery of CR-sEVs (CR-sEVs/MN) at the tendon-to-bone junction, incorporating tendon-derived decellularized extracellular matrix in the base to facilitate tendon repair. CR-sEVs/MN mitigates inflammation, promotes fibrocartilage regeneration, and enhances tendon healing, thereby improving biomechanical strength and shoulder joint function in a rat RCR model. Combining CR-sEVs with this triphasic microneedle delivery system presents a promising strategy for enhancing tendon-to-bone healing in clinical settings.

A Versatile Cryomicroneedle Patch for Traceable Photodynamic Therapy

Photodynamic therapy (PDT) continues to encounter multifarious hurdles, stemming from the ineffectual preservation and delivery system of photosensitizers, the dearth of imaging navigation, and the antioxidant/hypoxic tumor microenvironment. Herein, a versatile cryomicroneedle patch (denoted as CMN-CCPH) is developed for traceable PDT. The therapeutic efficacy is further amplified by catalase (CAT)-induced oxygen (O2) generation and Cu2+-mediated glutathione (GSH) depletion. The CMN-CCPH is composed of cryomicroneedle (CMN) as the vehicle and CAT-biomineralized copper phosphate nanoflowers (CCP NFs) loaded with hematoporphyrin monomethyl ether (HMME) as the payload. Importantly, the bioactive function of HMME and CAT can be optimally maintained under the protection of CCPH and CMN for a duration surpassing 60 days, leading to bolstered bioavailability and notable enhancements in PDT efficacy. The in vivo visualization of HMME and oxyhemoglobin saturation (sO2) monitored by fluorescence (FL)/photoacoustic (PA) duplex real-time imaging unveils the noteworthy implications of CMN-delivered CCPH for intratumoral enrichment of HMME and O2 with reduced systemic toxicity. This versatile CMN patch demonstrates distinct effectiveness in neoplasm elimination, underscoring its promising clinical prospects.

A Multifunctional Herb-Derived Glycopeptide Hydrogel for Chronic Wound Healing

Chronic wounds constitute an increasingly prevalent global healthcare issue, characterized by recurring bacterial infections, pronounced oxidative stress, compromised functionality of immune cells, unrelenting inflammatory reactions, and deficits in angiogenesis. In response to these multifaceted challenges, the study introduced a stimulus-responsive glycopeptide hydrogel constructed by oxidized Bletilla striata polysaccharide (OBSP), gallic acid-grafted ε-Polylysine (PLY-GA), and paeoniflorin-loaded micelles (MIC@Pae), called OBPG&MP. The hydrogel emulates the structure of glycoprotein fibers of the extracellular matrix (ECM), exhibiting exceptional injectability, self-healing, and biocompatibility. It adapts responsively to the inflammatory microenvironment of chronic wounds, sequentially releasing therapeutic agents to eradicate bacterial infection, neutralize reactive oxygen species (ROS), modulate macrophage polarization, suppress inflammation, and encourage vascular regeneration and ECM remodeling, playing a critical role across the inflammatory, proliferative, and remodeling phases of wound healing. Both in vitro and in vivo studies confirmed the efficacy of OBPG&MP hydrogel in regulating the wound microenvironment and enhancing the regeneration and remodeling of chronic wound skin tissue. This research supports the vast potential for herb-derived multifunctional hydrogels in tissue engineering and regenerative medicine.

Ta4C3 Nanosheets as a Novel Therapeutic Platform for Photothermal-Driven ROS Scavenging and Immune Activation against Antibiotic-Resistant Infections in Diabetic Wounds

The accumulation of excessive reactive oxygen species (ROS) and recurrent infections with drug-resistant bacteria pose significant challenges in diabetic wound infections, often leading to impediments in wound healing. Addressing this, there is a critical demand for novel strategies dedicated to treating and preventing diabetic wounds infected with drug-resistant bacteria. Herein, 2D tantalum carbide nanosheets (Ta4C3 NSs) have been synthesized through an efficient and straightforward approach, leading to the development of a new, effective nanoplatform endowed with notable photothermal properties, biosafety, and diverse ROS scavenging capabilities, alongside immunogenic attributes for diabetic wound treatment and prevention of recurrent drug-resistant bacterial infections. The Ta4C3 NSs exhibit remarkable photothermal performance, effectively eliminating methicillin-resistant Staphylococcus aureus (MRSA) and excessive ROS, thus promoting diabetic wound healing. Furthermore, Ta4C3 NSs enhance dendritic cell activation, further triggering T helper 1 (TH1)/TH2 immune responses, leading to pathogen-specific immune memory against recurrent MRSA infections. This nanoplatform, with its significant photothermal and immunomodulatory effects, holds vast potential in the treatment and prevention of drug-resistant bacterial infections in diabetic wounds.

New light-illuminated silk road: emerging silk fibroin-based optical biomedical sensors

Biomedical silk protein optics has become the subject of intensive research aimed at solving the challenges associated with traditional medical devices in terms of biocompatibility and performance balance. With its significant potential for biomedical applications in the field of drug storage and wound monitoring, it is dedicated to reducing the perturbation of neighbouring tissues. The transparency and biocompatibility of silk proteins make them ideal materials in the field of optical device fabrication, effectively overcoming the challenges posed by conventional materials. In this paper, we explore in detail the complex aspects of the design, synthesis and application related to biomedical silk protein optical devices and comprehensively analyse the potential use of silk protein-centric microstructures (e.g., micropillars, microneedles, and photonic crystals) in the development of optical devices. This review also offers insights into the challenges of applying silk protein optical devices in healthcare and their future trends, aiming to provide a comprehensive overview of the advances, potential impacts and emerging research directions in the field of biomedical silk protein optical devices.

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.

Exosomes and Macrophages: Bidirectional Mutual Regulation in the Treatment of Diabetic Complications

Purpose

The bidirectional regulation of macrophages and exosomes provides a meaningful research direction for the treatment of complications arising from both type 1 and type 2 diabetes mellitus. However, there is currently no comprehensive evaluation of the bidirectional regulatory role of macrophages and exosomes in diabetic complications. In this review, we aim to provide the detailed process of the bidirectional regulation mechanism of macrophages and exosomes, and how macrophage-associated exosomes use this mechanism to make it better applied to clinical practice through biotechnology.

Methods

Therefore, we summarized the bidirectional regulation mechanism of macrophages and exosomes and the application based on the bidirectional regulation mechanism from two aspects of inflammation and insulin resistance.

Results

As key regulators of the immune system, macrophages are crucial in the progression of diabetic complications due to their significant impact on the regulation of cellular metabolism, inflammation, and insulin sensitivity. Furthermore, exosomes, as innovative mediators of intercellular communication, transport miRNAs, proteins, and various bioactive molecules, influencing the occurrence and progression of diabetic complications through the regulation of inflammation and insulin resistance. The bidirectional regulation between macrophages and exosomes provides a promising pathway for the treatment of diabetic complications aimed at regulating the immune response and improving insulin sensitivity.

Conclusions

Understanding the complexity of the interaction between macrophages and exosomes can advance the treatment of diabetic complications and drug development, and bringing more innovative and effective treatment strategies for diabetic complications.

Smart Microneedle Arrays Integrating Cell-Free Therapy and Nanocatalysis to Treat Liver Fibrosis

Liver fibrosis is a chronic pathological condition lacking specific clinical treatments. Stem cells, with notable potential in regenerative medicine, offer promise in treating liver fibrosis. However, stem cell therapy is hindered by potential immunological rejection, carcinogenesis risk, efficacy variation, and high cost. Stem cell secretome-based cell-free therapy offers potential solutions to address these challenges, but it is limited by low delivery efficiency and rapid clearance. Herein, an innovative approach for in situ implantation of smart microneedle (MN) arrays enabling precisely controlled delivery of multiple therapeutic agents directly into fibrotic liver tissues is developed. By integrating cell-free and platinum-based nanocatalytic combination therapy, the MN arrays can deactivate hepatic stellate cells. Moreover, they promote excessive extracellular matrix degradation by more than 75%, approaching normal levels. Additionally, the smart MN arrays can provide hepatocyte protection while reducing inflammation levels by ≈70-90%. They can also exhibit remarkable capability in scavenging almost 100% of reactive oxygen species and alleviating hypoxia. Ultimately, this treatment strategy can effectively restrain fibrosis progression. The comprehensive in vitro and in vivo experiments, supplemented by proteome and transcriptome analyses, substantiate the effectiveness of the approach in treating liver fibrosis, holding immense promise for clinical applications.

Silk Fibroin Microneedles Loaded with Lipopolysaccharide-Pretreated Bone Marrow Mesenchymal Stem Cell-Derived Exosomes for Oral Ulcer Treatment

Oral ulcers, superficial lesions on the surface of the oral mucosa, have a high incidence rate, and their main symptoms include local pain and erosion. Lipopolysaccharide (LPS)-preconditioned bone marrow mesenchymal stem cells and their secreted exosomes (LPS-pre-Exos) have been shown to promote recovery in various inflammatory conditions and wounds. However, studies documenting LPS-pre-Exos as a therapeutic intervention for oral mucosal-like diseases are lacking. In this study, we prepared a silk fibroin microneedle (MN) patch consisting of LPS-pre-Exos and zeolitic imidazolate framework-8 (ZIF-8) that localized at the tip and base, respectively, and used this MN patch for oral ulcer treatment. Upon insertion into the oral mucosa, continuous LPS-pre-Exos release was observed, which promoted macrophage polarization and tissue healing. Additionally, the ZIF-8 framework in the MN patch facilitated the controlled release of Zn2+, which demonstrated potent antimicrobial properties via synergistic effects. The in vitro experimental results showed that the silk fibroin MN patch can continuously release LPS-pre-Exos and Zn2+ for more than 7 days. Thus, the LPS-pre-Exos and ZIF-8-loaded silk fibroin MN patch exhibited good anti-inflammatory and antibacterial properties, promoting oral ulcer healing, and showed good histocompatibility. Hence, it may represent a potentially valuable strategy for facilitating oral ulcer healing.