Dissolvable Microneedles Coupled with Nanofiber Dressings Eradicate Biofilms via Effectively Delivering a Database-Designed Antimicrobial Peptide

Microneedle technology for enhanced topical treatment of skin infections

Skin infections caused by microbes such as bacteria, fungi, and viruses often lead to aberrant skin functions and appearance, eventually evolving into a significant risk to human health. Among different drug administration paradigms for skin infections, microneedles (MNs) have demonstrated superiority mainly because of their merits in enhancing drug delivery efficiency and reducing microbial resistance. Also, integrating biosensing functionality to MNs offers point-of-care wearable medical devices for analyzing specific pathogens, disease status, and drug pharmacokinetics, thus providing personalized therapy for skin infections. Herein, we do a timely update on the development of MN technology in skin infection management, with a special focus on how to devise MNs for personalized antimicrobial therapy. Notably, the advantages of state-of-the-art MNs for treating skin infections are pointed out, which include hijacking sequential drug transport barriers to enhance drug delivery efficiency and delivering various therapeutics (e.g., antibiotics, antimicrobial peptides, photosensitizers, metals, sonosensitizers, nanoenzyme, living bacteria, poly ionic liquid, and nanomoter). In addition, the nanoenzyme-based multimodal antimicrobial therapy is highlighted in addressing intractable infectious wounds. Furthermore, the MN-based biosensors used to identify pathogen types, track disease status, and quantify antibiotic concentrations are summarized. The limitations of antimicrobial MNs toward clinical translation are offered regarding large-scale production, quality control, and policy guidance. Finally, the future development of biosensing MNs with easy-to-use and intelligent properties and MN-based wearable drug delivery for home-based therapy are prospected. We hope this review will provide valuable guidance for future development in MN-mediated topical treatment of skin infections.

Revolutionizing pressure ulcer regeneration: Unleashing the potential of extracellular matrix-derived temperature-sensitive injectable antioxidant hydrogel for superior stem cell therapy

Pressure ulcers are a common issue in elderly and medically compromised individuals, posing significant challenges in healthcare. Human umbilical cord mesenchymal stem cells (HUMSCs) offer therapeutic benefits like inflammation modulation and tissue regeneration, yet challenges in cell survival, retention, and implantation rates limit their clinical application. Hydrogels in three-dimensional (3D) stem cell culture mimic the microenvironment, improving cell survival and therapeutic efficacy. A thermosensitive injectable hydrogel (adEHG) combining gallic acid-modified hydroxybutyl chitosan (HBC-GA) with soluble extracellular matrix (adECM) has been developed to address these challenges. The hybrid hydrogel, with favorable physical and chemical properties, shields stem cells from oxidative stress and boosts their therapeutic potential by clearing ROS. The adEHG hydrogel promotes angiogenesis, cell proliferation, and collagen deposition, further enhancing inflammation modulation and wound healing through the sustained release of therapeutic factors and cells. Additionally, the adEHG@HUMSC composite induces macrophage polarization towards an M2 phenotype, which is crucial for wound inflammation inhibition and successful healing. Our research significantly propels the field of stem cell-based therapies for pressure ulcer treatment and underscores the potential of the adEHG hydrogel as a valuable tool in advancing regenerative medicine.

Photothermal Conjugated Polymer Microneedle with Biofilm Elimination and Angiogenesis for Diabetic Wound Healing

Diabetic wounds are highly susceptible to bacterial infection, which can lead to the formation of bacterial biofilms, making diabetic wound healing a major challenge. In this study, a composited microneedle that incorporated drug-loaded conjugated polymer nanoparticles and basic fibroblast growth factor was prepared to eliminate biofilms and promote vascular regeneration. This microneedle released minocycline under near-infrared (NIR) light, effectively penetrating bacterial biofilms. The photothermal properties of the conjugated polymers, combined with the antibacterial action of minocycline, contribute to the eradication of biofilms and the elimination of drug-resistant bacteria. Moreover, it regulated the wound microenvironment by reducing the level of oxidative stress, as well as the production of inflammatory factors at the wound site. Meanwhile, it effectively boosted cell migration and promoted angiogenesis to accelerate diabetic wound healing. This composited microneedle for biofilm elimination represents a promising approach for promoting diabetic wound healing.

Microbial production systems and optimization strategies of antimicrobial peptides: a review

Antibiotic resistance has become a public safety issue of the twenty-first century, posing a growing threat and drawing increased attention. Compared to traditional antibiotics, antimicrobial peptides (AMPs), as naturally produced small peptides, can target multiple pathways within pathogens and render them less prone to developing resistance. This makes them promising alternatives to antibiotics. However, traditional chemical synthesis methods face challenges, such as high costs, low yields, and poor stability, limiting the large-scale industrial production of AMPs. Despite extensive research to improve AMP production efficiency, issues such as low yields and complex extraction processes continue to pose significant barriers to commercial application. Therefore, there is an urgent need for new biosynthesis strategies and optimization methods to enhance AMP production efficiency and quality. This review summarizes the sources, classification, mechanisms of action and recent advances in the microbial synthesis of AMPs. It also explores innovative production methods, including recombinant microbial expression systems, fusion tags, codon optimization, tandem multimer expression, and hybrid peptide expression. Furthermore, we review the applications of gene editing technologies and artificial intelligence in AMP production, providing new perspectives and strategies for efficient, large-scale AMP production.

Tailoring Design of Microneedles for Drug Delivery and Biosensing

Microneedles (MNs) are emerging as versatile tools for both therapeutic drug delivery and diagnostic monitoring. Unlike hypodermic needles, MNs achieve these applications with minimal or no pain and customizable designs, making them suitable for personalized medicine. Understanding the key design parameters and the challenges during contact with biofluids is crucial to optimizing their use across applications. This review summarizes the current fabrication techniques and design considerations tailored to meet the distinct requirements for drug delivery and biosensing applications. We further underscore the current state of theranostic MNs that integrate drug delivery and biosensing and propose future directions for advancing MNs toward clinical use.

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.

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.

Antimicrobial Peptides: A Promising Alternative to Conventional Antimicrobials for Combating Polymicrobial Biofilms

Polymicrobial biofilms adhere to surfaces and enhance pathogen resistance to conventional treatments, significantly contributing to chronic infections in the respiratory tract, oral cavity, chronic wounds, and on medical devices. This review examines antimicrobial peptides (AMPs) as a promising alternative to traditional antibiotics for treating biofilm-associated infections. AMPs, which can be produced as part of the innate immune response or synthesized therapeutically, have broad-spectrum antimicrobial activity, often disrupting microbial cell membranes and causing cell death. Many specifically target negatively charged bacterial membranes, unlike host cell membranes. Research shows AMPs effectively inhibit and disrupt polymicrobial biofilms and can enhance conventional antibiotics' efficacy. Preclinical and clinical research is advancing, with animal studies and clinical trials showing promise against multidrug-resistant bacteria and fungi. Numerous patents indicate increasing interest in AMPs. However, challenges such as peptide stability, potential cytotoxicity, and high production costs must be addressed. Ongoing research focuses on optimizing AMP structures, enhancing stability, and developing cost-effective production methods. In summary, AMPs offer a novel approach to combating biofilm-associated infections, with their unique mechanisms and synergistic potential with existing antibiotics positioning them as promising candidates for future treatments.

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.

Emerging Technological Advancement for Chronic Wound Treatment and Their Role in Accelerating Wound Healing

Chronic wounds are a major healthcare burden and may severely affect the social, mental, and economic status of the patients. Any impairment in wound healing stages due to underlying factors leads to a prolonged healing time and subsequently to chronic wounds. Traditional approaches for the treatment of chronic wounds include dressing free local therapy, dressing therapy, and tissue engineering based scaffold therapies. However, traditional therapies need improvisation and have been advanced through breakthrough technologies. The present review spans traditional therapies and further gives an extensive account of advancements in the treatment of chronic wounds. Cutting edge technologies, such as 3D printing, which includes inkjet printing, fused deposition modeling, digital light processing, extrusion-based printing, microneedle array-based therapies, gene therapy, which includes microRNAs (miRNAs) therapy, and smart wound dressings for real time monitoring of wound conditions through assessment of pH, temperature, oxygen, moisture, metabolites, and their use for planning of better treatment strategies have been discussed in detail. The review further gives the future direction of treatments that will aid in lowering the healthcare burden caused due to chronic wounds.

Innovative freeze-drying technique in the fabrication of dissolving microneedle patch: Enhancing transdermal drug delivery efficiency

Microneedle patch (MNP) has become a hot research topic in the field of transdermal drug delivery due to its ability to overcome the stratum corneum barrier. Among the various types of microneedles, dissolving microneedles represent one of the most promising transdermal delivery methods. However, the most used method for preparing dissolving microneedles, namely microfabrication, suffers from issues such as long drying time, susceptibility to humidity, and large batch-to-batch variability, which limit the development of dissolving microneedles. In this study, we report for the first time a method for preparing dissolving microneedles using freeze-drying technology. We screened substrates suitable for freeze-dried microneedle patch (FD-MNP) and used coating technology to enhance the mechanical strength of FD-MNP, allowing them to meet the requirements for skin penetration. We successfully prepared FD-MNP using hyaluronic acid as the substrate and insulin as the model drug. Scanning electron microscopy revealed that the microneedles had a porous structure. After coating, the mechanical strength of the microneedles was 0.61 N/Needle, and skin penetration rate was 97%, with a penetration depth of 215 μm. The tips of the FD-MNP dissolved completely within approximately 60 s after skin penetration, which is much faster than conventional MNP (180 s). In vitro transdermal experiments showed that the FD-MNP shortened the lag time for transdermal delivery of rhodamine 123 and insulin compared to conventional MNP, indicating a faster transdermal delivery rate. Pharmacological experiments showed that the FD-MNP lowered mouse blood glucose levels more effectively than conventional MNP, with a relative pharmacological availability of 96.59 ± 2.84%, higher than that of conventional MNP (84.34 ± 3.87%), P = 0.0095. After storage under 40℃ for two months, the insulin content within the FD-MNP remained high at 95.27 ± 4.46%, which was much higher than that of conventional MNP (58.73 ± 3.71%), P < 0.0001. In conclusion, freeze-drying technology is a highly valuable method for preparing dissolving microneedles with potential applications in transdermal drug delivery.

Emerging strategies for treating medical device and wound-associated biofilm infections

Bacterial infections represent a significant global threat to human health, leading to considerable economic losses through increased healthcare costs and reduced productivity. One major challenge in treating these infections is the presence of biofilms - structured bacterial communities that form protective barriers, making traditional treatments less effective. Additionally, the rise of antibiotic-resistant bacteria has exacerbated treatment difficulties. To address these challenges, researchers are developing and exploring innovative approaches to combat biofilm-related infections. This mini-review highlights recent advancements in the following key areas: surface anti-adhesion technologies, electricity, photo/acoustic-active materials, endogenous mimicking agents, and innovative drug delivery systems. These strategies aim to prevent biofilm formation, disrupt existing biofilms, and enhance the efficacy of antimicrobial treatments. Currently, these approaches show great potential for applications in medical fields such as medical device and wound - associated biofilm infections. By summarizing these developments, this mini-review provides a comprehensive resource for researchers seeking to advance the management and treatment of biofilm-associated infections.

A 3D radially aligned nanofiber scaffold co-loaded with LL37 mimetic peptide and PDGF-BB for the management of infected chronic wounds

Diabetic foot ulcers, pressure ulcers, and bedsores can easily develop into chronic wounds with bacterial infections, complicating wound healing. This work reports a two-step strategy for treating infected chronic wounds. Firstly, LL37 mimetic peptide-W379 peptides were rapidly released to eliminate the bacterial biofilm on the wound. Then, 3D radially aligned nanofiber scaffolds loaded with W379 antimicrobial peptide and PDGF-BB were used to treat the wound to prevent bacterial infection recurrence and promote angiogenesis and granulation tissue regeneration, thereby accelerating wound healing. In the presented study, we found that the combined use of burst and controlled release of W379 antimicrobial peptide effectively clears the bacterial biofilm and prevents the recurrence of bacterial infection. Additionally, we found that the removal of the bacterial biofilm contributed to modulating the local inflammatory response from a pro-inflammatory type to a pro-regenerative type. Furthermore, the use of PDGF-BB significantly promotes neovascularization and granulation tissue regeneration in the wound bed, resulting in accelerating re-epithelialization and wound closure. Our study provides a promising treatment method for the repair of infected chronic wounds.

Emerging Trends in Dissolving-Microneedle Technology for Antimicrobial Skin-Infection Therapies

Skin and soft-tissue infections require significant consideration because of their prolonged treatment duration and propensity to rapidly progress, resulting in severe complications. The primary challenge in their treatment stems from the involvement of drug-resistant microorganisms that can form impermeable biofilms, as well as the possibility of infection extending deep into tissues, thereby complicating drug delivery. Dissolving microneedle patches are an innovative transdermal drug-delivery system that effectively enhances drug penetration through the stratum corneum barrier, thereby increasing drug concentration at the site of infection. They offer highly efficient, safe, and patient-friendly alternatives to conventional topical formulations. This comprehensive review focuses on recent advances and emerging trends in dissolving-microneedle technology for antimicrobial skin-infection therapy. Conventional antibiotic microneedles are compared with those based on emerging antimicrobial agents, such as quorum-sensing inhibitors, antimicrobial peptides, and antimicrobial-matrix materials. The review also highlights the potential of innovative microneedles incorporating chemodynamic, nanoenzyme antimicrobial, photodynamic, and photothermal antibacterial therapies. This review explores the advantages of various antimicrobial therapies and emphasizes the potential of their combined application to improve the efficacy of microneedles. Finally, this review analyzes the druggability of different antimicrobial microneedles and discusses possible future developments.

Advances in Polysaccharide-Based Microneedle Systems for the Treatment of Ocular Diseases

The eye, a complex organ isolated from the systemic circulation, presents significant drug delivery challenges owing to its protective mechanisms, such as the blood-retinal barrier and corneal impermeability. Conventional drug administration methods often fail to sustain therapeutic levels and may compromise patient safety and compliance. Polysaccharide-based microneedles (PSMNs) have emerged as a transformative solution for ophthalmic drug delivery. However, a comprehensive review of PSMNs in ophthalmology has not been published to date. In this review, we critically examine the synergy between polysaccharide chemistry and microneedle technology for enhancing ocular drug delivery. We provide a thorough analysis of PSMNs, summarizing the design principles, fabrication processes, and challenges addressed during fabrication, including improving patient comfort and compliance. We also describe recent advances and the performance of various PSMNs in both research and clinical scenarios. Finally, we review the current regulatory frameworks and market barriers that are relevant to the clinical and commercial advancement of PSMNs and provide a final perspective on this research area.

Nanozyme-Incorporated Microneedles for the Treatment of Chronic Wounds

Acute wounds are converted to chronic wounds due to advanced age and diabetic complications. Nanozymes catalyze ROS production to kill bacteria without causing drug resistance, while microneedles (MNs) can break through the skin barrier to deliver drugs effectively. Nanozymes can be intergrateded into MNs delivery systems to improve painless drug delivery. It can also reduce the effective dose of drug sterilization while increasing delivery efficiency and effectively killing wounded bacteria while preventing drug resistance. This paper describes various types of metal nanozymes from previous studies and compares their mutual enhancement with nanozymes. The pooled results show that the MNs, through material innovation, are able to both penetrate the scab and deliver nanozymes and exert additional anti-inflammatory and bactericidal effects. The catalytic effect of some of the nanozymes can also accelerate the lysis of the MNs or create a cascade reaction against inflammation and infection. However, the issue of increased toxicity associated with skin penetration and clinical translation remains a challenge. This study reviews the latest published results and corresponding challenges associated with the use of MNs combined with nanozymes for the treatment of wounds, providing further information for future research.

Design Strategy of Microneedle Systems for Skin Wound Healing: Based on the Structure of Tips and Therapeutic Methodologies

The skin, being the largest organ of the human body, is susceptible to damage resulting in wounds that are vulnerable to pathogenic attacks and fail to provide effective protection for internal tissues. Therefore, it is crucial to expedite wound healing. In recent years, microneedles have garnered significant attention as an innovative drug delivery system owing to their noninvasive and painless administration, simplified application process, precise control over drug release, and versatile loading capabilities. Consequently, they hold immense potential for the treatment of skin wound. This review presents a comprehensive design strategy for the microneedle system in promoting skin wound healing. First, the process of skin wound healing and the characteristics of specific wounds are elucidated. The design strategies for microneedles are subsequently presented and classified based on their structural and therapeutic methodologies. Finally, a succinct recapitulation of the previously discussed points and a prospective analysis are provided.

Numerical modeling of ultrasound-triggered microneedle-mediated delivery of drug particles into bacterial biofilms

Ultrasonic microneedle patches, a class of ultrasound-driven transdermal drug delivery systems, are promising in addressing bacterial biofilms. This device has been proven to be more effective in treating Staphylococcus aureus biofilms than drug in free solution. However, there exists a notable gap in understanding how various excitation conditions and material parameters affect drug delivery efficiency. This study aims to fill this void by conducting an comprehensive multi-physics numerical analysis of ultrasonic microneedle patches, with the ultimate goal of enhancing drug delivery. First, we investigate the impact of various ultrasound frequencies on drug penetration depths. The findings reveal that local resonance can accelerate drug release within a shorter time window (first 1.5 h), whereas non-resonant frequencies enable more profound and prolonged diffusion. This information is crucial for medical professionals in selecting the most effective frequency for optimal drug administration. Furthermore, our investigation extends to the effects of applied voltage on temperature distribution, a critical aspect for ensuring medical safety during the application of these patches. Additionally, we examine how particles of different sizes respond to acoustic pressure and streaming fields, providing valuable insights for tailoring drug delivery strategies to specific therapeutic needs. Overall, our findings offer comprehensive guidelines for the effective use of ultrasonic microneedle patches, potentially shifting the paradigm in patient care and enhancing the overall quality of life.

Ultrasound-Responsive Aligned Piezoelectric Nanofibers Derived Hydrogel Conduits for Peripheral Nerve Regeneration

Nerve guidance conduits (NGCs) are considered as promising treatment strategy and frontier trend for peripheral nerve regeneration, while their therapeutic outcomes are limited by the lack of controllable drug delivery and available physicochemical cues. Herein, novel aligned piezoelectric nanofibers derived hydrogel NGCs with ultrasound (US)-triggered electrical stimulation (ES) and controllable drug release for repairing peripheral nerve injury are proposed. The inner layer of the NGCs is the barium titanate piezoelectric nanoparticles (BTNPs)-doped polyvinylidene fluoride-trifluoroethylene [BTNPs/P(VDF-TrFE)] electrospinning nanofibers with improved piezoelectricity and aligned orientation. The outer side of the NGCs is the thermoresponsive poly(N-isopropylacrylamide) hybrid hydrogel with bioactive drug encapsulation. Such NGCs can not only induce neuronal-oriented extension and promote neurite outgrowth with US-triggered wireless ES, but also realize the controllable nerve growth factor release with the hydrogel shrinkage under US-triggered heating. Thus, the NGC can positively accelerate the functional recovery and nerve axonal regeneration of rat models with long sciatic nerve defects. It is believed that the proposed US-responsive aligned piezoelectric nanofibers derived hydrogel NGCs will find important applications in clinic neural tissue engineering.

Advancements in Aerogel Technology for Antimicrobial Therapy: A Review

This paper explores the latest advancements in aerogel technology for antimicrobial therapy, revealing their interesting capacity that could improve the current medical approaches for antimicrobial treatments. Aerogels are attractive matrices because they can have an antimicrobial effect on their own, but they can also provide efficient delivery of antimicrobial compounds. Their interesting properties, such as high porosity, ultra-lightweight, and large surface area, make them suitable for such applications. The fundamentals of aerogels and mechanisms of action are discussed. The paper also highlights aerogels' importance in addressing current pressing challenges related to infection management, like the limited drug delivery alternatives and growing resistance to antimicrobial agents. It also covers the potential applications of aerogels in antimicrobial therapy and their possible limitations.

Physiological Microenvironment Dependent Self-Cross-Linking of Multifunctional Nanohybrid for Prolonged Antibacterial Therapy via Synergistic Chemodynamic-Photothermal-Biological Processes

Herein, a multifunctional nanohybrid (PL@HPFTM nanoparticles) was fabricated to perform the integration of chemodynamic therapy, photothermal therapy, and biological therapy over the long term at a designed location for continuous antibacterial applications. The PL@HPFTM nanoparticles consisted of a polydopamine/hemoglobin/Fe2+ nanocomplex with comodification of tetrazole/alkene groups on the surface as well as coloading of antimicrobial peptides and luminol in the core. During therapy, the PL@HPFTM nanoparticles would selectively cross-link to surrounding bacteria via tetrazole/alkene cycloaddition under chemiluminescence produced by the reaction between luminol and overexpressed H2O2 at the infected area. The resulting PL@HPFTM network not only significantly damaged bacteria by Fe2+-catalyzed ROS production, effective photothermal conversion, and sustained release of antimicrobial peptides but dramatically enhanced the retention time of these therapeutic agents for prolonged antibacterial therapy. Both in vitro and in vivo results have shown that our PL@HPFTM nanoparticles have much higher bactericidal efficiency and remarkably longer periods of validity than free antibacterial nanoparticles.

Exosomes-carried curcumin based on polysaccharide hydrogel promote flap survival

Flap grafting is a common technique used to repair skin defects in orthopedics and plastic and reconstructive surgeries. However, oxidative stress injury caused by ischemia and ischemia-reperfusion injury at the distal end of the skin flap can cause flap necrosis. Curcumin is a natural compound with anti-inflammatory and antioxidant properties that tackle oxidative stress. However, its applicability is limited by its poor water solubility. Exosomes are membranous vesicles that can be loaded with hydrophobic drugs. They are widely studied in drug delivery applications and can be investigated to augment curcumin efficiency. In this study, a self-healing oxidized pullulan polysaccharide-carboxymethylated chitosan composite hydrogel was used as a curcumin-loaded exosome delivery system to evaluate its impact on the viability of skin flaps. The hydrogel exhibited good self-healing properties that allowed the continuous and stable release of drugs. It had anti-inflammatory and antioxidant properties that could reduce oxidative stress damage due to early ischemia and hypoxia of the skin flap in vitro. Moreover, this composite hydrogel attenuated inflammatory responses, promoted angiogenesis, and reduced the distal necrosis of the flap in vivo. Therefore, our hydrogel provides a novel strategy for skin flap graft protection with reduced necrosis and the potential for broad clinical applications.

It Takes Two to Tangle: Microneedle Patches Co-delivering Monoclonal Antibodies and Engineered Antimicrobial Peptides Effectively Eradicate Wound Biofilms

Wound biofilms pose a great clinical challenge. Herein, this work reports a dissolvable microneedle patch for dual delivery of monoclonal antibodies anti-PBP2a and engineers antimicrobial peptides W379. In vitro antibacterial efficacy testing with microneedle patches containing a combination of 250 ng mL-1 W379 and 250 ng mL-1 anti-BPB2a decreases the bacterial count from ≈3.31 × 107 CFU mL-1 to 1.28 × 102 CFU mL-1 within 2 h without eliciting evident cytotoxicity. Ex vivo testing indicates W379 and anti-PBP2a co-loaded microneedle patch displayed a remarkable reduction of bacterial load by ≈7.18 log CFU after administered only once within 48 h. The bacterial count is significantly diminished compared to the treatment by either W379 or anti-PBP2a-loaded alone microneedle patches. When administered twice within 48 h, no bacteria are identified. Further in vivo study also reveals that after two treatments of W379 and anti-PBP2a co-loaded PVP microneedle patches within 48 h, the bacterial colonies are undetectable in a type II diabetic mouse wound biofilm model. Taken together, W379 and anti-PBP2a co-loaded PVP microneedle patches hold great promise in treating wound biofilms.

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

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

Dissolving microneedle system containing Ag nanoparticle-decorated silk fibroin microspheres and antibiotics for synergistic therapy of bacterial biofilm infection

Most cases of delayed wound healing are associated with bacterial biofilm infections due to high antibiotic resistance. To improve patient compliance and recovery rates, it is critical to develop minimally invasive and efficient methods to eliminate bacterial biofilms as an alternative to clinical debridement techniques. Herein, we develop a dissolving microneedle system containing Ag nanoparticles (AgNPs)-decorated silk fibroin microspheres (SFM-AgNPs) and antibiotics for synergistic treatment of bacterial biofilm infection. Silk fibroin microspheres (SFM) are controllably prepared in an incompatible system formed by a mixture of protein and carbohydrate solutions by using a mild all-aqueous phase method and serve as biological templates for the synthesis of AgNPs. The SFM-AgNPs exert dose- and time-dependent broad-spectrum antibacterial effects by inducing bacterial adhesion. The combination of SFM-AgNPs with antibiotics breaks the limitation of the antibacterial spectrum and achieves better efficacy with reduced antibiotic dosage. Using hyaluronic acid (HA) as the soluble matrix, the microneedle system containing SFM-AgNPs and anti-Gram-positive coccus drug (Mupirocin) inserts into the bacterial biofilms with sufficient strength, thereby effectively delivering the antibacterial agents and realizing good antibiofilm effect on Staphylococcus aureus-infected wounds. This work demonstrates the great potential for the development of novel therapeutic systems for eradicating bacterial biofilm infections.

A Comprehensive Review of Recent Research into the Effects of Antimicrobial Peptides on Biofilms-January 2020 to September 2023

Microbial biofilm formation creates a persistent and resistant environment in which microorganisms can survive, contributing to antibiotic resistance and chronic inflammatory diseases. Increasingly, biofilms are caused by multi-drug resistant microorganisms, which, coupled with a diminishing supply of effective antibiotics, is driving the search for new antibiotic therapies. In this respect, antimicrobial peptides (AMPs) are short, hydrophobic, and amphipathic peptides that show activity against multidrug-resistant bacteria and biofilm formation. They also possess broad-spectrum activity and diverse mechanisms of action. In this comprehensive review, 150 publications (from January 2020 to September 2023) were collected and categorized using the search terms 'polypeptide antibiotic agent', 'antimicrobial peptide', and 'biofilm'. During this period, a wide range of natural and synthetic AMPs were studied, of which LL-37, polymyxin B, GH12, and Nisin were the most frequently cited. Furthermore, although many microbes were studied, Staphylococcus aureus and Pseudomonas aeruginosa were the most popular. Publications also considered AMP combinations and the potential role of AMP delivery systems in increasing the efficacy of AMPs, including nanoparticle delivery. Relatively few publications focused on AMP resistance. This comprehensive review informs and guides researchers about the latest developments in AMP research, presenting promising evidence of the role of AMPs as effective antimicrobial agents.

Recent progress of polymeric microneedle-assisted long-acting transdermal drug delivery

Microneedle (MN)-assisted drug delivery technology has gained increasing attention over the past two decades. Its advantages of self-management and being minimally invasive could allow this technology to be an alternative to hypodermic needles. MNs can penetrate the stratum corneum and deliver active ingredients to the body through the dermal tissue in a controlled and sustained release. Long-acting polymeric MNs can reduce administration frequency to improve patient compliance and therapeutic outcomes, especially in the management of chronic diseases. In addition, long-acting MNs could avoid gastrointestinal reactions and reduce side effects, which has potential value for clinical application. In this paper, advances in design strategies and applications of long-acting polymeric MNs are reviewed. We also discuss the challenges in scale manufacture and regulations of polymeric MN systems. These two aspects will accelerate the effective clinical translation of MN products.

A Bacterial Responsive Microneedle Dressing with Hydrogel Backing Layer for Chronic Wound Treatment

The treatment of chronic wounds still presents great challenges due to being infected by biofilms and the damaged healing process. The current treatments do not address the needs of chronic wounds. In this study, a highly effective dressing (Dox-DFO@MN Hy) for the treatment of chronic wounds is described. This dressing combines the advantages of microneedles (MNs) and hydrogels in the treatment of chronic wounds. MNs is employed to debride the biofilms and break down the wound barrier, providing rapid access to therapeutic drugs from hydrogel backing layer. Importantly, to kill the pathogenic bacteria in the biofilms specifically, Doxycycline hydrochloride (Dox) is wrapped into the polycaprolactone (PCL) microspheres that have lipase-responsive properties and loaded into the tips of MNs. At the same time, hydrogel backing layer is used to seal the wound and accelerate wound healing. Benefiting from the combination of two advantages of MNs and hydrogel, the dressing significantly reduces the bacteria in the biofilms and effectively promotes angiogenesis and cell migration in vitro. Overall, Dox-DFO@MN Hy can effectively treat chronic wounds infected with biofilms, providing a new idea for the treatment of chronic wounds.

Enhancing diabetic wound healing: advances in electrospun scaffolds from pathogenesis to therapeutic applications

Diabetic wounds are a significant subset of chronic wounds characterized by elevated levels of inflammatory cytokines, matrix metalloproteinases (MMPs), and reactive oxygen species (ROS). They are also associated with impaired angiogenesis, persistent infection, and a high likelihood of hospitalization, leading to a substantial economic burden for patients. In severe cases, amputation or even mortality may occur. Diabetic foot ulcers (DFUs) are a common complication of diabetes, with up to 25% of diabetic patients being at risk of developing foot ulcers over their lifetime, and more than 70% ultimately requiring amputation. Electrospun scaffolds exhibit a structural similarity to the extracellular matrix (ECM), promoting the adhesion, growth, and migration of fibroblasts, thereby facilitating the formation of new skin tissue at the wound site. The composition and size of electrospun scaffolds can be easily adjusted, enabling controlled drug release through fiber structure modifications. The porous nature of these scaffolds facilitates gas exchange and the absorption of wound exudate. Furthermore, the fiber surface can be readily modified to impart specific functionalities, making electrospinning nanofiber scaffolds highly promising for the treatment of diabetic wounds. This article provides a concise overview of the healing process in normal wounds and the pathological mechanisms underlying diabetic wounds, including complications such as diabetic foot ulcers. It also explores the advantages of electrospinning nanofiber scaffolds in diabetic wound treatment. Additionally, it summarizes findings from various studies on the use of different types of nanofiber scaffolds for diabetic wounds and reviews methods of drug loading onto nanofiber scaffolds. These advancements broaden the horizon for effectively treating diabetic wounds.

Integration of polysaccharide electrospun nanofibers with microneedle arrays promotes wound regeneration: A review

Utilizing electrospun nanofibers and microneedle arrays in wound regeneration has been practiced for several years. Researchers have recently asserted that using multiple methods concurrently might enhance efficiency, despite the inherent strengths and weaknesses of each individual approach. The combination of microneedle arrays with electrospun nanofibers has the potential to create a drug delivery system and wound healing method that offer improved efficiency and accuracy in targeting. The use of microneedles with nanofibers allows for precise administration of pharmaceuticals due to the microneedles' capacity to pierce the skin and the nanofibers' role as a drug reservoir, resulting in a progressive release of drugs over a certain period of time. Electrospun nanofibers have the ability to imitate the extracellular matrix and provide a framework for cellular growth and tissue rejuvenation, while microneedle arrays show potential for enhancing tissue regeneration and enhancing the efficacy of wound healing. The integration of electrospun nanofibers with microneedle arrays may be customized to effectively tackle particular obstacles in the fields of wound healing and drug delivery. However, some issues must be addressed before this paradigm may be fully integrated into clinical settings, including but not limited to ensuring the safety and sterilization of these products for transdermal use, optimizing manufacturing methods and characterization of developed products, larger-scale production, optimizing storage conditions, and evaluating the inclusion of multiple therapeutic and antimicrobial agents to increase the synergistic effects in the wound healing process. This research examines the combination of microneedle arrays with electrospun nanofibers to enhance the delivery of drugs and promote wound healing. It explores various kinds of microneedle arrays, the materials and processes used, and current developments in their integration with electrospun nanofibers.

Multifunctional MXene-doped photothermal microneedles for drug-resistant bacteria-infected wound healing

Skin injuries and drug-resistant bacterial infections pose serious challenges to human health. It is essential to establish a novel multifunctional platform with good anti-infection and wound-healing abilities. In this study, a new MXene-doped composite microneedle (MN) patch with excellent mechanical strength and photothermal antibacterial and ROS removal properties has been developed for infected wound healing. When the MN tips carrying the MXene nanosheets are inserted into the cuticle of the skin, they will quickly dissolve and subsequently release the nanomaterials into the subcutaneous infection area. Under 808 nm NIR irradiation, the MXene, as a "nano-thermal knife", sterilizes and inhibits bacterial growth through synergistic effects of sharp edges and photothermal antibacterial activity. Furthermore, ROS caused by injury and infection can be cleared by MXene-doped MNs to avoid excessive inflammatory responses. Based on the synergistic antibacterial and antioxidant strategy, the MXene-doped MNs have demonstrated excellent wound-healing properties in an MRSA-infected wound model, such as promoting re-epithelialization, collagen deposition, and angiogenesis and inhibiting the expression of pro-inflammatory factors. Therefore, the multifunctional MXene-doped MN patches provide an excellent alternative for clinical drug-resistant bacteria-infected wound management.

Novel microneedle platforms for the treatment of wounds by drug delivery: A review

The management and treatment of wounds are complex and pose a substantial financial burden to the patient. However, the complex environment of wounds leads to inadequate drug absorption to achieve the desired therapeutic effect. As a novel technological platform, microneedles are widely used in drug delivery because of their multiple drug loading, multistage drug release, and multiple designs of topology. This study systematically summarizes and analyzes the manufacturing methods and limitations of different microneedles, as well as the latest research advances in pain management, drug delivery, and healing promotion, and presents the challenges and opportunities for clinical applications. On this basis, the development of microneedles in external wound repair and management is envisioned, and it is hoped that this study can provide guidelines for the design of microneedle systems in different application contexts, including the selection of materials, preparation methods, and structural design, to achieve better healing and regeneration results.

An Integrated Therapeutic and Preventive Nanozyme-Based Microneedle for Biofilm-Infected Diabetic Wound Healing

The healing of biofilm-infected diabetic wounds characterized by a deteriorative tissue microenvironment represents a substantial clinical challenge. Current treatments remain unsatisfactory due to the limited antibiofilm efficacy caused by weak tissue and biofilm permeability of drugs and the risk of reinfection during the healing process. To address these issues, an integrated therapeutic and preventive nanozyme-based microneedle (denoted as Fe2 C/GOx@MNs) is engineered. The dissolvable tips with enough mechanical strength can deliver and rapidly release Fe2 C nanoparticles (NPs)/glucose oxidase (GOx) in the biofilm active regions, enhancing tissue and biofilm permeability of Fe2 C NPs/GOx, ultimately achieving highly efficient biofilm elimination. Meanwhile, the chitosan backing layer can not only act as an excellent physical barrier between the wound bed and the external environment, but also prevent the bacterial reinvasion during wound healing with its superior antibacterial property. Significantly, the biofilm elimination and reinfection prevention abilities of Fe2 C/GOx@MNs on wound healing are proved on methicillin-resistant Staphylococcus aureus-biofilm-infected diabetic mouse model with full-thickness wound. Together, these results demonstrate the promising clinical application of Fe2 C/GOx@MNs in biofilm-infected wound healing.

Poly(pentahydropyrimidine)‐Based Hybrid Hydrogel with Synergistic Antibacterial and Pro‐Angiogenic Ability for the Therapy of Diabetic Foot Ulcers

Bacterial infection and impaired angiogenesis make the treatment of diabetic foot ulcers (DFU) extremely challenging. Cationic polymers are expected to treat infected wounds due to their excellent antibacterial properties, but still, it is difficult to meet the therapeutic needs of pro‐angiogenesis and anti‐infections due to their simple construction units and outmoded synthesis methods. Herein, a cationic poly(pentahydropyrimidine) (PPHP) library with strong modifiability is synthesized to construct a hybrid hydrogel with synergistic therapeutic effects for the treatment of infected DFUs. It is found that the as‐synthesized hybrid hydrogel can up‐regulate angiogenesis‐related gene (HIF‐1, VEGF, and bFGFR/bFGF) expression and targeted disruption of bacterial cell membranes, which finally promotes the healing of infected DFU (wound healing rate: 92%) within 10 days. This hydrogel, thus, holds great promise in developing new strategies to significantly enhance the treatment of DFU and other bacterial‐infected pathological diagnoses.

Highly active nisin coated polycaprolactone electrospun fibers against both Staphylococcus aureus and Pseudomonas aeruginosa

In this study, a wound dressing of electrospun polycaprolactone (PCL) fibers incorporating the antimicrobial peptide (AMP) nisin was fabricated. Nisin was physically adsorbed to the PCL fibers and tested for antibacterial activity against both Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). The PCL fibers had an average diameter of 1.16 μm ± 0.42 μm and no significant change in diameter occurred after nisin adsorption. X-ray photoelectron spectroscopy (XPS) analysis of the fibers detected nitrogen indicative of adsorbed nisin and the signal was used to quantify the levels of coverage on the fiber surfaces. In vitro nisin release studies showed a burst release profile with 80 % of the nisin being released from the fibers within 30 min. Air plasma pre-treatment of the PCL fibers to render them hydrophilic improved nisin loading and release. Antibacterial testing was performed using minimum inhibitory concentration (MIC) and surface attachment assays. The released nisin remained active against both Gram positive S. aureus and Gram negative P. aeruginosa, which has previously been difficult to achieve with single polymer fiber systems. Mammalian cell culture of the nisin coated fibers with L-929 mouse fibroblasts and human epidermal keratinocytes (HEKa) showed that the nisin did not have a significant effect on the biocompatibility of the PCL fibers. The results presented here demonstrate that the physical adsorption, which is a post-treatment, overcomes the potential limitations of harsh chemicals and fabrication conditions of electrospinning from organic solvents and provides a drug loading system having effective antibacterial properties in wound dressings.

Cerium oxide nanoparticles in diabetic foot ulcer management: Advances, limitations, and future directions

Diabetic foot ulcer (DFU) is one of the most serious complications of diabetes, potentially resulting in wound infection and amputation under severe circumstances. Oxidative stress and dysbiosis are the primary factors that delay wound healing, posing challenges to effective treatment. Unfortunately, conventional approaches in these aspects have proven satisfactory in achieving curative outcomes. Recent research has increasingly focused on using nanoparticles, leveraging their potential in wound dressing and medication delivery. Their unique physical properties further enhance their therapeutic effectiveness. Among these nanoparticles, cerium oxide nanoparticles (CONPs) have garnered attention due to their notable beneficial effects on oxidative stress and microbial abundance, thus representing a promising therapeutic avenue for DFU. This review comprehensively assesses recent studies on CONPs in treating DFU. Furthermore, we elaborate on the wound healing process, ceria synthesis, and incorporating CONPs with other materials. Crucially, a thorough evaluation of CONPs' toxicity as a novel metallic nanomaterial for therapeutic use must precede their formal clinical application. Additionally, we identify the current challenges CONPs encounter and propose future directions for their development.

Magnesium/gallic acid bioMOFs laden carbonized mushroom aerogel effectively heals biofilm-infected skin wounds

Biofilm-infected acute skin wounds are still one of the significant challenges that need to be solved urgently in wound healing. Herein, we reported a magnesium/gallic acid bio-MOFs laden carbonized mushroom aerogel (QMOFs-PCMA) combined with photothermal therapy for eradicating biofilms in skin wounds. The design of bioMOFs is mainly responsible for regulating immunity. In vitro, it exhibited ROS clearance and antioxidant ability. In vivo, it could regulate local immune responses from pro-inflammatory status to pro-regenerative status, resulting in decreased inflammatory cytokines expression and increased anti-inflammatory cytokines expression. The carbonized mushroom aerogel is mainly responsible for photothermal therapy (PTT), and the polydopamine and bioMOFs could enhance the photothermal conversion efficiency and stability of carbonized aerogels. The carbonized aerogel in combination with PTT could eradicate S. aureus biofilm in both in vitro and in vivo studies and clear E. coli biofilms in vitro studies. The biofilm clearance and improved inflammatory responses laid a good foundation for wound healing, resulting in the granulation tissue formation, re-epithelialization, and angiogenesis significantly enhanced in the QMOFs-PCMA + NIR group. Our results indicate that the QMOFs-PCMA combined with photothermal therapy may provide a promising treatment for biofilm-infected skin wounds.

Functional Microneedle Patch for Wound Healing and Biological Diagnosis and Treatment

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

Antibacterial micro/nanomotors: advancing biofilm research to support medical applications

Multi-drug resistant (MDR) bacterial infections are gradually increasing in the global scope, causing a serious burden to patients and society. The formation of bacterial biofilms, which is one of the key reasons for antibiotic resistance, blocks antibiotic penetration by forming a physical barrier. Nano/micro motors (MNMs) are micro-/nanoscale devices capable of performing complex tasks in the bacterial microenvironment by transforming various energy sources (including chemical fuels or external physical fields) into mechanical motion or actuation. This autonomous movement provides significant advantages in breaking through biological barriers and accelerating drug diffusion. In recent years, MNMs with high penetrating power have been used as carriers of antibiotics to overcome bacterial biofilms, enabling efficient drug delivery and improving the therapeutic effectiveness of MDR bacterial infections. Additionally, non-antibiotic antibacterial strategies based on nanomaterials, such as photothermal therapy and photodynamic therapy, are continuously being developed due to their non-invasive nature, high effectiveness, and non-induction of resistance. Therefore, multifunctional MNMs have broad prospects in the treatment of MDR bacterial infections. This review discusses the performance of MNMs in the breakthrough and elimination of bacterial biofilms, as well as their application in the field of anti-infection. Finally, the challenges and future development directions of antibacterial MNMs are introduced.

The Progress in the Application of Dissolving Microneedles in Biomedicine

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

Microneedle-based cell delivery and cell sampling for biomedical applications

Cell-based therapeutics are novel therapeutic strategies that can potentially treat many presently incurable diseases through novel mechanisms of action. Cell therapies may benefit from the ease, safety, and efficacy of administering therapeutic cells. Despite considerable recent technological and biological advances, several barriers remain to the clinical translation and commercialization of cell-based therapies, including low patient compliance, personal handling inconvenience, poor biosafety, and limited biocompatibility. Microneedles (MNs) are emerging as a promising biomedical device option for improved cell delivery with little invasion, pain-free administration, and simplicity of disposal. MNs have shown considerable promise in treating a wide range of diseases and present the potential to improve cell-based therapies. In this review, we first summarized the latest advances in the various types of MNs developed for cell delivery and cell sampling. Emphasis was given to the design and fabrication of various types of MNs based on their structures and materials. Then we focus on the recent biomedical applications status of MNs-mediated cell delivery and sampling, including tissue repair (wound healing, heart repair, and endothelial repair), cancer treatment, diabetes therapy, cell sampling, and other applications. Finally, the current status of clinical application, potential perspectives, and the challenges for clinical translation are also highlighted.

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

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

Cell-free fat extract-loaded microneedles attenuate inflammation-induced apoptosis and mitochondrial damage in tendinopathy

Existing clinical treatments for tendinopathy mainly focus on reducing pain, whereas inhibiting or reversing disease progression remains challenging. Local therapeutic drugs, such as glucocorticoids, cause adverse effects on the metabolism of tendon tissues and injection-related complications. Therefore, new administration modalities for tendinopathy need to be developed. In this study, we designed a hydrogel-based microneedle (MN) system for the long-term transdermal delivery of our novel biological cell-free fat extract (CEFFE) to treat tendinopathies. We found that CEFFE-loaded MNs (CEFFE-MNs) had good biosafety and inhibited lipopolysaccharide (LPS)-induced apoptosis and matrix degradation in Achilles tendon cells of rats. The Achilles tendons of rats returned to their maximum mechanical strength after applying CEFFE-MNs. The administration of CEFFE-MNs had better anti-apoptosis and tendon repair-promoting effects than CEFEF injections in vivo. Transcriptome sequencing indicated that the anti-apoptosis effect of CEFFE-MNs was highly related to tumor necrosis factor (TNF) signaling. CEFFE-MNs inhibited the expression of TNF, TNF receptor 1, and downstream nuclear factor-kappa B signaling. Additionally, CEFFE-MNs rescued LPS-induced mitochondrial dynamics in tendon cells via the TNF-Drp1 axis. Our study reports a novel CEFFE-MN system that exhibits long-term anti-inflammatory and anti-apoptotic effects, suggesting it as a new treatment route for tendinopathy with broad clinical translation prospects.

Applications of Degradable Hydrogels in Novel Approaches to Disease Treatment and New Modes of Drug Delivery

Hydrogels are particularly suitable materials for loading drug delivery agents; their high water content provides a biocompatible environment for most biomolecules, and their cross-linked nature protects the loaded agents from damage. During delivery, the delivered substance usually needs to be released gradually over time, which can be achieved by degradable cross-linked chains. In recent years, biodegradable hydrogels have become a promising technology in new methods of disease treatment and drug delivery methods due to their many advantageous properties. This review briefly discusses the degradation mechanisms of different types of biodegradable hydrogel systems and introduces the specific applications of degradable hydrogels in several new methods of disease treatment and drug delivery methods.

A Cu@ZIF-8 encapsulated antibacterial and angiogenic microneedle array for promoting wound healing

Skin wounds caused by external injuries remain a serious challenge in clinical practice. Wound dressings that are antibacterial, pro-angiogenic, and have potent regeneration capacities are highly desirable for wound healing. In this study, a minimally invasive and wound-friendly Cu@ZIF-8 encapsulated PEGDA/CMCS microneedle (MN) array was fabricated using the molding method to promote wound healing. The MNs had good biocompatibility, excellent mechanical strength, as well as strong antibacterial properties and pro-angiogenic effects. When incubated with H2O2, Cu@ZIF-8 nanoparticles generated reactive oxygen species, which contributed to their antibacterial properties. Due to the oxidative stress of the cupric ions released from Cu@ZIF-8 and the anti-bacterial capability of the PEGDA/CMCS hydrogel scaffold, such an MN array presents excellent antibacterial activity. Moreover, with the continuous release of Cu ions from the scaffold, such MNs are effective in terms of promoting angiogenesis. With considerable biocompatibility and a minimally invasive approach, the degradable MN array composed of PEGDA/CMCS possessed superior capabilities to continuously and steadily release the loaded ingredients and avoid secondary damage to the wound. Benefiting from these features, the Cu@ZIF-8 encapsulated degradable MN array can dramatically accelerate epithelial regeneration and neovascularization. These results indicated that the combination of Cu@ZIF-8 and degradable MN arrays is valuable in promoting wound healing, which opened a new window for treatment of skin defection.

Recent Advances in Functional Wound Dressings

Significance: Nowadays, the wound dressing is no longer limited to its primary wound protection ability. Hydrogel, sponge-like material, three dimensional-printed mesh, and nanofiber-based dressings with incorporation of functional components, such as nanomaterials, growth factors, enzymes, antimicrobial agents, and electronics, are able to not only prevent/treat infection but also accelerate the wound healing and monitor the wound-healing status. Recent Advances: The advances in nanotechnologies and materials science have paved the way to incorporate various functional components into the dressings, which can facilitate wound healing and monitor different biological parameters in the wound area. In this review, we mainly focus on the discussion of recently developed functional wound dressings. Critical Issues: Understanding the structure and composition of wound dressings is important to correlate their functions with the outcome of wound management. Future Directions: "All-in-one" dressings that integrate multiple functions (e.g., monitoring, antimicrobial, pain relief, immune modulation, and regeneration) could be effective for wound repair and regeneration.

Scarless wound healing programmed by core-shell microneedles

Effective reprogramming of chronic wound healing remains challenging due to the limited drug delivery efficacy hindered by physiological barriers, as well as the inappropriate dosing timing in distinct healing stages. Herein, a core-shell structured microneedle array patch with programmed functions (PF-MNs) is designed to dynamically modulate the wound immune microenvironment according to the varied healing phases. Specifically, PF-MNs combat multidrug-resistant bacterial biofilm at the early stage via generating reactive oxygen species (ROS) under laser irradiation. Subsequently, the ROS-sensitive MN shell gradually degrades to expose the MN core component, which neutralizes various inflammatory factors and promotes the phase transition from inflammation to proliferation. In addition, the released verteporfin inhibits scar formation by blocking Engrailed-1 (En1) activation in fibroblasts. Our experiments demonstrate that PF-MNs promote scarless wound repair in mouse models of both acute and chronic wounds, and inhibit the formation of hypertrophic scar in rabbit ear models.

Combating Bacterial Biofilms: Current and Emerging Antibiofilm Strategies for Treating Persistent Infections

Biofilms are intricate multicellular structures created by microorganisms on living (biotic) or nonliving (abiotic) surfaces. Medically, biofilms often lead to persistent infections, increased antibiotic resistance, and recurrence of infections. In this review, we highlighted the clinical problem associated with biofilm infections and focused on current and emerging antibiofilm strategies. These strategies are often directed at disrupting quorum sensing, which is crucial for biofilm formation, preventing bacterial adhesion to surfaces, impeding bacterial aggregation in viscous mucus layers, degrading the extracellular polymeric matrix, and developing nanoparticle-based antimicrobial drug complexes which target persistent cells within the biofilm core. It is important to acknowledge, however, that the use of antibiofilm agents faces obstacles, such as limited effectiveness in vivo, potential cytotoxicity to host cells, and propensity to elicit resistance in targeted biofilm-forming microbes. Emerging next generation antibiofilm strategies, which rely on multipronged approaches, were highlighted, and these benefit from current advances in nanotechnology, synthetic biology, and antimicrobial drug discovery. The assessment of current antibiofilm mitigation approaches, as presented here, could guide future initiatives toward innovative antibiofilm therapeutic strategies. Enhancing the efficacy and specificity of some emerging antibiofilm strategies via careful investigations, under conditions that closely mimic biofilm characteristics within the human body, could bridge the gap between laboratory research and practical application.

Janus porous polylactic acid membranes with versatile metal-phenolic interface for biomimetic periodontal bone regeneration

Conventional treatment to periodontal and many other bone defects requires the use of barrier membranes to guided tissue regeneration (GTR) and guided bone regeneration (GBR). However, current barrier membranes normally lack of the ability to actively regulate the bone repairing process. Herein, we proposed a biomimetic bone tissue engineering strategy enabled by a new type of Janus porous polylactic acid membrane (PLAM), which was fabricated by combining unidirectional evaporation-induced pore formation with subsequent self-assembly of a bioactive metal-phenolic network (MPN) nanointerface. The prepared PLAM-MPN simultaneously possesses barrier function on the dense side and bone-forming function on the porous side. In vitro, the presence of MPN nanointerface potently alleviated the proinflammatory polarization of mice bone marrow-derived macrophages (BMDMs), induced angiogenesis of human umbilical vein endothelial cells (HUVECs), and enhanced the attachment, migration and osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). The implantation of PLAM-MPN into rat periodontal bone defects remarkably enhanced bone regeneration. This bioactive MPN nanointerface within a Janus porous membrane possesses versatile capacities to regulate cell physiology favoring bone regeneration, demonstrating great potential as GTR and GBR membranes for clinical applications.