Advanced drug delivery systems and artificial skin grafts for skin wound healing

Tight orchestration of wound healing phase through metal-organic compounds

Cutaneous wound healing remains a common health problem. Metal-organic frameworks (MOFs) have emerged as an advanced therapeutic platform for promoted wound healing. However, there is a lack of MOF particles possessing excellent stability, biocompatibility, and reactive oxygen species (ROS) scavenging ability for tight orchestration of wound healing. Herein, we synthetize therapeutic MOF particles named PgC3Zn and employ them as skin sprays for wound repair. At the inflammatory stage, the pH- and ROS-responsive Zn2+ release of PgC3Zn alleviates oxidative stress and exerts antibacterial and anti-inflammatory efficacy. During the proliferation stage, PgC3Zn promote the migration and proliferation of fibroblasts, the re-epithelialization of keratinocytes, and the angiogenesis of endothelial cells. During the remodeling stage, PgC3Zn effectively facilitate the wound closure and collagen deposition. Moreover, multiple endogenous growth factors have been identified to contribute to the wound healing process. Importantly, PgC3Zn exhibit excellent biocompatibility and remarkably accelerate the healing process in both acute and infected rat full-thickness skin wound models in vivo. Consistently, transcriptomic data illustrate the multi-stage and multi-functional regulation effects of PgC3Zn in promoting wound healing. This study proposes versatile and biocompatible PgC3Zn MOF particles with potentials for enhancing the management of acute and infected skin wounds.

Biodegradable multifunctional hyaluronic acid hydrogel microneedle band-aids for accelerating skin wound healing

Wound healing for various diseases and wounds such as diabetes and burns remains a major biomedical challenge. Conventional monotherapy is ineffective, and the efficacy of drug delivery is limited by the depth of drug penetration. In this study, we develop a novel, multifunctional, dissolvable hyaluronic acid (HA) microneedle patch (MN-LTT). Microneedling is biocompatible and delivers the drug in a painless and non-invasive manner. Lidocaine and thrombin are mixed with HA hydrogel and loaded onto the needle tips of the MN-LTT, which facilitates wound repair by continuously delivering the drug deep into the dermis for rapid analgesia and hemostasis. In addition, the backing layer of the MN-LTT is composed of tetracycline hydrochloride and HA hydrogel, and its excellent antimicrobial properties further accelerate wound healing. In a mouse full-thickness skin wound model, MN-LTT accelerated cell proliferation and granulation tissue growth, reduced inflammatory-factor levels, and restored collagen deposition, resulting in complete wound healing within seven days. Thus, the proposed microneedle delivery system achieved rapid hemostatic, analgesic, and bactericidal effects, providing a safer and more effective strategy for wound healing. These features make the multifunctional HA microneedle patch potentially valuable for clinical applications.

pH and Glucose Dual-Responsive Hydrogels Promoted Diabetic Wound Healing by Remodeling the Wound Microenvironment

The microenvironment of diabetic wounds is complicated and characterized by hyperglycemia, hyperinflammation, persistent infection, hypoxia, and ischemia, making wound restoration and healing extremely challenging. Therefore, functional hydrogel dressings with the ability to regulate the microenvironment of diabetic wounds are a promising strategy for the treatment of diabetic wounds. In this study, a pH/glucose dual-responsive hydrogel based on phenylboric acid-modified carboxymethyl chitosan (CMCSPBA), aldehyde-terminated polyethylene glycol (PEGCHO), and polyvinyl alcohol (PVA) has been developed for diabetic wound treatment via Schiff base and phenylboric ester interactions. Glucose oxidase (GOX), catalase (CAT), and deferoxamine mesylate (DFO) are incorporated into the hydrogel to endow it with multi-functionality. In the hyperglycemic environment of diabetic wounds, a benign feedback loop is formed through the synergistic action of each component of the hydrogel, which enables the reshaping of the microenvironment of diabetic wounds by adjusting the pH and glucose, alleviating oxidative stress and hypoxia, regulating the inflammatory response, inhibiting bacterial infection, and promoting angiogenesis, thus accelerating diabetic wound healing in streptozotocin (STZ)-induced diabetic mice.

MXenes and MXene-based composites for biomedical applications

MXenes, a novel class of two-dimensional materials, have recently emerged as promising candidates for biomedical applications due to their specific structural features and exceptional physicochemical and biological properties. These materials, characterized by unique structural features and superior conductivity, have applications in tissue engineering, cancer detection and therapy, sensing, imaging, drug delivery, wound treatment, antimicrobial therapy, and medical implantation. Additionally, MXene-based composites, incorporating polymers, metals, carbon nanomaterials, and metal oxides, offer enhanced electroactive and mechanical properties, making them highly suitable for engineering electroactive organs such as the heart, skeletal muscle, and nerves. However, several challenges, including biocompatibility, functional stability, and scalable synthesis methods, remain critical for advancing their clinical use. This review comprehensively overviews MXenes and MXene-based composites, their synthesis, properties, and broad biomedical applications. Furthermore, it highlights the latest progress, ongoing challenges, and future perspectives, aiming to inspire innovative approaches to harnessing these versatile materials for next-generation medical solutions.

Innovating chitosan-based bioinks for dermal wound healing: Current progress and future prospects

The field of three-dimensional (3D) bio/printing, known as additive manufacturing (AM), heavily relies on bioinks possessing suitable mechanical properties and compatibility with living cells. Among the array of potential hydrogel precursor materials, chitosan (CS) has garnered significant attention due to its remarkable physicochemical and biological attributes. These attributes include biodegradability, nontoxicity, antimicrobial properties, wound healing promotion, and immune system activation, making CS a highly appealing hydrogel-based bioink candidate. This review explores the transformative potential of CS-based bioink for enhancing dermal wound healing therapies. We highlight CS's unique qualities that make it an optimal choice for bioink development. Advancements in 3D bio/printing technology for tissue engineering (TE) are discussed, followed by an examination of strategies for CS-based bioink formulation and their impacts on wound healing. To address the progress in translating advanced wound healing from lab to clinic, we highlight the current and ongoing research in CS-based bioink for 3D bio/printing in skin wound healing applications. Finally, we explore current evidence, commercialization prospects, emerging innovations like 4D printing, and the challenges and future directions in this promising field.

Green synthesized ZnO and ZnO-based composites for wound healing applications

In recent years, zinc oxide nanoparticles (ZnO NPs) have gained much attention in biomedical applications because of their distinctive physicochemical features such as low toxicity and biocompatible properties. Traditional methods to produce ZnO NPs sometimes include harmful substances and considerable energy consumption, causing environmental issues and potential health risks. Nowadays, the concern of ZnO production has moved toward environmentally friendly and sustainable synthesis methods, using natural extracts or plant-based precursors. This review discusses the green synthesis of ZnO NPs utilizing various plant extracts for wound healing applications. Moreover, ZnO NPs have antibacterial characteristics, which can prevent infection, a substantial obstacle in wound healing. Their ability to maintain inflammation, proliferation, oxidative stress, and promote angiogenesis proves their critical role in wound closure. In addition, ZnO NPs can also be easily and ideally incorporated with wound dressings and scaffolds such as hydrogel, chitosan, cellulose, alginate, and other materials, due to their exceptional mechanical properties. The latest publication of green synthesis of ZnO NPs and their applications for wound healing has been discussed. Therefore, this review provides a current update of knowledge on the sustainable and biocompatible ZnO NPs for specific applications, i.e., wound healing applications. In addition, the green synthesis of ZnO NPs using plant extracts also provides a particular approach in terms of material preparation, which is different from previous review articles.

Multifunctional alginate-sinapic acid/arginine-strontium hydrogel for promoting diabetic wound healing

Sodium alginate (Alg), sinapic acid (SA), arginine (Arg), strontium carbonate (SrCO₃), and D-gluconic acid δ-lactone (GDL) were employed to construct an ionically crosslinked sodium alginate-sinapic acid/arginine‑strontium (ASASG) hydrogel. This study aims to evaluate its potential for enhancing diabetic wound repair through combined ionic crosslinking and bioactive component synergy. The hydrogel demonstrates exceptional swelling properties conducive to the absorption of wound exudate. Furthermore, it exhibits remarkable antibacterial and antioxidant activities. The ASASG hydrogel shows good biocompatibility, facilitates hemostasis and promotes the migration of NIH 3 T3 fibroblasts. Animal studies have revealed that ASASG hydrogel significantly enhances wound healing, accelerates re-epithelialization, and fosters collagen deposition in diabetic rats. Furthermore, ASASG hydrogels mitigated inflammatory cell infiltration by down-regulating IL-6 expression and concurrently up-regulating TGF-β expression. Notably, ASASG hydrogels also stimulate angiogenesis by enhancing the expressions of VEGF and bFGF. Therefore, the use of ASASG hydrogel in the treatment of diabetic wounds is a possible therapeutic approach.

Polyaminoglycoside nanosystem expressing antimicrobial peptides for multistage chronic wound management

Chronic wounds are difficult to heal due to pathogenic microbial colonization and dysregulation of healing cascades, necessitating novel therapeutic strategies. This study developed a multifunctional nanosystem by integrating the antimicrobial peptide LL37 with cationic polyaminoglycoside (SS-HPT), constructing a self-sustaining "AMP factory" to achieve multi-stage modulation of the wound healing. Validation through cell-level experiments and in vivo dual models (mechanical injury and bacterial infection) in immunocompromised rats demonstrated the system's unique dual intracellular-extracellular pathogen-killing capability, significantly accelerating the wound healing process. Transcriptomic analysis revealed that its mechanism involves the dual effects of suppressing pro-inflammatory factor expression and activating tissue repair pathways. Histological evidence confirmed that the system promotes angiogenesis, enhances re-epithelialization rates, and guides orderly collagen fiber deposition. This nanosystem, combining efficient AMP delivery and integrated therapeutic strategies, achieves three-dimensional synergy in microbial clearance, immune microenvironment regulation, and tissue matrix remodeling, providing theoretical and technical foundations for a paradigm shift in chronic wound treatment.

Diabetic wound healing breakthrough: theaflavin-3, 3'-digallate nanoparticles@hydrogel activates the TGF-β1/SMAD3 pathway

BACKGROUND

Diabetes patients face an elevated wound infection susceptibility and delayed healing processes. Currently, no existing literature has reported on the effect and mechanism of theaflavin-3, 3'-digallate nanoparticles (TFDG NPS) and TFDG NPS@hydrogels on diabetic wounds.

PURPOSE

Given that the treatment options for diabetic wound are limited, the aim of this study is to develop an innovative therapeutic approach to address diabetic wounds.

METHODS

The TFDG NPS were prepared using ionic cross-linking, and they were then characterized. The biocompatibility of the TFDG NPS and TFDG NPS@hydrogel was assessed using a Cell Counting Kit-8 (CCK-8) assay and live/dead staining on HK-2 cells in vitro. Diabetic ICR mice were induced through intraperitoneal injection of streptozocin (STZ). They were then subjected to the creation of two full-thickness wounds on their dorsal areas. The effect and mechanism of the TFDG NPS and TFDG NPS@hydrogel on wound healing in diabetic mice were evaluated using a histological analysis, a western blot analysis, and molecular docking.

RESULTS

The optimal TFDG NPS proportion was found to be TFDG:Gelatin (Gel):Chitosan (CS) = 2:1:1. Images photographed using a transmission electron microscope (TEM) revealed that the TFDG NPS appeared spherical, with a diameter of approximately 140 ± 20 nm. The favorable bio-compatibility of the TFDG NPS and TFDG NPS@hydrogel was confirmed using cell experiments. Animal studies demonstrated that both the TFDG NPS and TFDG NPS@hydrogel enhanced collagen fiber accumulation and new blood vessel density, reduced F4/80 infiltration, and upregulated the expression levels of TGF-β1, SMAD3, Collagen I, and α-SMA. The potential mechanism may involve activation of the TGF-β1/SMAD3 pathway, stimulating the secretion of Collagen I and α-SMA, and thereby facilitating wound closure in diabetic mice. The molecular docking results confirmed a high affinity between TFDG and TGF-β1/SMAD3.

CONCLUSION

TFDG NPS and TFDG NPS@hydrogel promoted wound closure in diabetic mice through the TFG-β1/SMAD3 pathway, thus exhibiting promising therapeutic potential for diabetic wound treatment.

Multifunctional hydrogel targeting senescence to accelerate diabetic wound healing through promoting angiogenesis

Diabetic wound healing remains a significant clinical challenge because of hyperglycaemia-induced cellular senescence, impaired angiogenesis, and chronic inflammation. To address these issues, we developed a multifunctional hydrogel (GelMA/PNS/Alg@IGF-1) that integrates gelatine methacryloyl (GelMA), Panax notoginseng saponins (PNS), and sodium alginate microspheres encapsulating insulin-like growth factor-1 (IGF-1). This hydrogel was engineered to achieve gradient and sustained release of bioactive agents to target senescence and promote vascular repair. In vitro studies demonstrated that the hydrogel significantly reduced oxidative stress, suppressed senescence markers and senescence-associated secretory phenotypes, and restored endothelial cell function under high-glucose conditions by inhibiting NF-κB pathway activation. Transcriptomic analysis revealed the modulation of pathways linked to inflammation, apoptosis, and angiogenesis. This hydrogel accelerated diabetic wound closure in a rat model in vivo and enhanced collagen deposition, granulation tissue formation, and neovascularization. Furthermore, the hydrogel mitigated oxidative stress and cellular senescence and promoted tissue remodelling. The synergistic effects of PNS and IGF-1 within the hydrogel established a pro-regenerative microenvironment to address both pathological ageing and vascular dysfunction. These findings highlight GelMA/PNS/Alg@IGF-1 as a promising therapeutic platform for diabetic wound management, as this material offers dual anti-senescence and proangiogenic efficacy to overcome the complexities of chronic wound healing.

Bioactivity of dressings based on platelet-rich plasma and Platelet-rich fibrin for tissue regeneration in animal model

BACKGROUND

Skin wounds are common injuries that affect quality of life and incur high costs. A considerable portion of healthcare resources in Western countries is allocated to wound treatment, mainly using mechanical, biological, or artificial dressings. Biological and artificial dressings, such as hydrogels, are preferred for their biocompatibility. Platelet concentrates, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), stand out for accelerating tissue repair and minimizing risks of allergies and rejection. This study developed PRF and PRP-based dressings to treat skin wounds in an animal model, evaluating their functionality and efficiency in accelerating the tissue repair process.

AIM

To develop wound dressings based on platelet concentrates and evaluating their efficiency in treating skin wounds in Wistar rats.

METHODS

Wistar rats, both male and female, were subjected to the creation of a skin wound, distributed into groups (n = 64/group), and treated with Carbopol (negative control); PRP + Carbopol; PRF + Carbopol; or PRF + CaCl2 + Carbopol, on days zero (D0), D3, D7, D14, and D21. PRP and PRF were obtained only from male rats. On D3, D7, D14, and D21, the wounds were analyzed for area, contraction rate, and histopathology of the tissue repair process.

RESULTS

The PRF-based dressing was more effective in accelerating wound closure early in the tissue repair process (up to D7), while PRF + CaCl2 seemed to delay the process, as wound closure was not complete by D21. Regarding macroscopic parameters, animals treated with PRF + CaCl2 showed significantly more crusting (necrosis) early in the repair process (D3). In terms of histopathological parameters, the PRF group exhibited significant collagenization at the later stages of the repair process (D14 and D21). By D21, fibroblast proliferation and inflammatory infiltration were higher in the PRP group. Animals treated with PRF + CaCl2 experienced a more pronounced inflammatory response up to D7, which diminished from D14 onwards.

CONCLUSION

The PRF-based dressing was effective in accelerating the closure of cutaneous wounds in Wistar rats early in the process and in aiding tissue repair at the later stages.

Management of Acute Hand Burns: A Survey of American Burn Association-Verified Burn Centers

Hand burns have a significant impact on the long-term function of burn patients. Recently, new protocols and technologies, such as dermal substitutes, have been introduced for the treatment of hand burns. This cross-sectional study investigates the preferred current management of acute hand burns and the role of dermal substitutes in treatment. A 10-question survey related to acute hand burns management was sent to 64 directors of American Burn Association (ABA)-verified burn centers. A total of 51.6% (n = 33) directors of ABA-verified burn centers responded to the survey. For the treatment of superficial partial-thickness hand burns, 90.9% preferred a nonoperative approach. Conversely, most respondents chose a single-stage excision and skin graft for deep partial-thickness hand burns (75.8%) and full-thickness hand burns (51.5%). However, for full-thickness hand burns, some surgeons prefer a 2-stage reconstruction involving excision and placement of a skin substitute (27.3%) or allograft (9.1%), followed by a skin graft. Only 6.1% would utilize a 3-stage reconstruction involving excision and allograft, excision and skin substitute, followed by skin grafting. Among surgeons who used skin substitutes (n = 26), Integra (42.3%) and Novosorb-Biodegradable Temporizing Matrix (23.1%) were preferred. The top reasons for choosing 1 specific dermal substitute were surgeon's preference (n = 20; 76.9%) and cost (n = 9; 34.6%). While a conservative nonoperative approach is preferred for superficial partial-thickness hand burns, excision and skin grafting as a 1-stage procedure remains the most common strategy for deep partial-thickness and full-thickness hand burns.

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.

The efficacy of miR-141-3p to facilitate the healing of wounds and prevent scarring in mice by blocking the JNK/ERK pathway via HDAC6 silencing

PURPOSE

Adipose-derived mesenchymal stem cells (ADSCs) exosomes (AD-Exos) are a novel and promising therapeutic approach for skin damage repair. This investigation seeks to assess the potential clinical utility of miR-141-3p found in AD-exos for expediting wound healing.

METHODS

ADSCs were isolated from the wounded patients' tissue and validated via flow cytometry, and the mineralization and adipogenic capabilities of ADSCs were assessed respectively. Additionally, exosomes were isolated and identified. miR-141-3p and HDAC6.protein level were tested. Full-thickness wound models were created on the backs of mice, HE staining, ELISA, and immunohistochemistry were used to assess the influences of AD-exos on wound healing, inflammation, and new blood vessel formation Western blot was to assess the related-protein levels of JNK/ERK pathway. AQ1 Meanwhile, Dual-Luciferase assay confirmed the relationship between miR-141-3p and HDAC6.

RESULTS

The isolated cells highly express surface markers of mesenchymal stem cells and possess the potential for multidirectional differentiation, confirming them to be ADSCs. And miR-141-3p down-regulated but HDAC6 up-regulated in the serum and AD-exos of wounded patients. miR-141-3p could negatively modulate HDAC6. The miR-141-3p in AD-exos accelerated wound healing in mice, mitigated inflammatory responses and scarring in the injured skin tissue, and promoted angiogenesis, moreover, AD-exos could diminish the phosphorylation of JNK and ERK, while HDAC6 overexpressed could weaken these impacts.

CONCLUSION

miR-141-3p in AD-exos can target down regulate HDAC6 expression and inhibit JNK/ERK signaling pathway activation, thereby reducing wound inflammation and promoting angiogenesis and wound healing in mice.

Hydrogel-based therapies for diabetic foot ulcers: recent developments and clinical implications

The diabetic foot ulcer is among the most serious diabetes-associated complications, with a long disease course considerably increasing the pain and economic burden of patients, leading to amputation and even death. High blood sugar is characteristic of diabetic foot ulcers, with insufficient blood supply, oxidative stress disorder, and high-risk bacterial infection posing great challenges for disease treatment. Advances in hydrogel dressings have shown potential for the management of diabetic foot ulcers involving multisystem lesions. This study comprehensively reviews the pathogenesis of diabetic foot ulcers and advances in hydrogel dressings in treating diabetic foot ulcers, providing innovative perspectives for assessing the nursing care requirements and associated clinical applications.

Collagen as a bio-ink for 3D printing: a critical review

The significance of three-dimensional (3D) bioprinting in the domain of regenerative medicine and tissue engineering is readily apparent. To create a multi-functional bioinspired structure, 3D bioprinting requires high-performance bioinks. Bio-inks refer to substances that encapsulate viable cells and are employed in the printing procedure to construct 3D objects progressive through successive layers. For a bio-ink to be considered high-performance, it must meet several critical criteria: printability, gelation kinetics, structural integrity, elasticity and strength, cell adhesion and differentiation, mimicking the native ECM, cell viability and proliferation. As an exemplar application, tissue grafting is used to repair and replace severely injured tissues. The primary considerations in this case include compatibility, availability, advanced surgical techniques, and potential complications after the operation. 3D printing has emerged as an advancement in 3D culture for its use as a regenerative medicine approach. Thus, additive technologies such as 3D bioprinting may offer safe, compatible, and fast-healing tissue engineering options. Multiple methods have been developed for hard and soft tissue engineering during the past few decades, however there are many limitations. Despite significant advances in 3D cell culture, 3D printing, and material creation, a gold standard strategy for designing and rebuilding bone, cartilage, skin, and other tissues has not yet been achieved. Owing to its abundance in the human body and its critical role in protecting and supporting human tissues, soft and hard collagen-based bioinks is an attractive proposition for 3D bioprinting. Collagen, offers a good combination of biocompatibility, controllability, and cell loading. Collagen made of triple helical collagen subunit is a protein-based organic polymer present in almost every extracellular matrix of tissues. Collagen-based bioinks, which create bioinspired scaffolds with multiple functionalities and uses them in various applications, is a represent a breakthrough in the regenerative medicine and biomedical engineering fields. This protein can be blended with a variety of polymers and inorganic fillers to improve the physical and biological performance of the scaffolds. To date, there has not been a comprehensive review appraising the existing literature surround the use of collagen-based bioink applications in 'soft' or 'hard' tissue applications. The uses of the target region in soft tissues include the skin, nerve, and cartilage, whereas in the hard tissues, it specifically refers to bone. For soft tissue healing, collagen-based bioinks must meet greater functional criteria, whereas hard tissue restoration requires superior mechanical qualities. Herein, we summarise collagen-based bioink's features and highlight the most essential ones for diverse healing situations. We conclude with the primary challenges and difficulties of using collagen-based bioinks and suggest future research objectives.

Injectable Silver Nanoparticle-Based Hydrogel Dressings with Rapid Shape Adaptability and Antimicrobial Activity

Burns and scalds often result in deep wounds that challenge adequate debridement and inflammation control using traditional sheet-like hydrogel dressings. Herein, we developed an antibacterial, injectable, and self-healing hydrogel (ADCM@Ag) by employing carboxymethyl chitosan (CMCS) for in situ green reduction of silver ions and utilizing a spontaneous Schiff base reaction with aldehyde-functionalized dextran (AD). SEM analysis revealed a porous structure within the hydrogel. Swelling and enzymatic degradation assays demonstrated that ADCM@Ag hydrogel possesses excellent fluid absorption capacity and biodegradability. Mechanical tests indicated good mechanical properties, allowing the hydrogel to withstand external forces when applied to animal wounds. The hydrogel exhibited good injectability, shape adaptability, and self-healing capability. Cell experiments showed that the ADCM@Ag hydrogel avoided the cytotoxicity caused by high concentrations of silver ions and had good cell compatibility. Antimicrobial assays showed that ADCM@Ag exhibited potent bactericidal effects against Gram-negative and Gram-positive bacteria, achieving at least 85% killing efficacy. Collectively, ADCM@Ag hydrogel has good potential for wound dressing applications.

Recent advances in the use of essential oils and their nanoformulations for wound treatment

Despite progress in medical and surgical treatments of wounds, bioactive compounds still offer an effective and safe approach to accelerate wound healing (WH). In this review, recent results of studies on WH by essential oils (EOs) and their terpenoids are reported. Mechanisms of action of these substances and their possible use in drug delivery systems (DDSs) for WH are discussed. EOs of 38 species from 16 families have been evaluated for their potential to treat wounds. Lamiaceae was the most representative family with 10 species, followed by Myrtaceae and Asteraceae. EOs improve WH by acting as anti-inflammatory, antioxidant, and antimicrobial agents. Some other EOs were involved by increasing expression of transforming growth factor (TGF), inhibition of several factors, including plasminogen activator inhibitor-1 (PAI-1), substitution of type III collagen by type I collagen, and up-regulation of insulin-like growth factor-1 (IGF-1), fibroblast growth factor 2 (FGF-2), and vascular endothelial growth factor (VEGF). These mechanisms improved repair of cells and increased proliferation. Alternatively, DDSs based on nanomaterials (NMs) used to carry EOs for WH are mainly based on nanoparticles (NPs), microparticles (MPs) and scaffolds. There is much evidence that EOs can promote WH. Advancement of nanotechnology in recent years has contributed to improving use of EO with DDSs in WH management. However, some limitations need to be addressed to achieve the translation of this technology into clinical applications for wound treatment.

Oxygen-Bonded Amorphous Transition Metal Dichalcogenides with pH-Responsive Reactive Oxygen Biocatalysis for Combined Antibacterial and Anti-inflammatory Therapies in Diabetic Wound Healing

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-Or) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-Or exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-Or demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-Or serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-Or, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-Or as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

Evaluation of the antibacterial properties of four bioactive biomaterials for chronic wound management

AIM

Chronic wound infections present a prevalent medical issue and a multifaceted problem that significantly impacts healthcare systems worldwide. Biofilms formed by pathogenic bacteria are fundamental virulence factors implicated in the complexity and persistence of bacterial-associated wound infections, leading to prolonged recovery times and increased risk of infection. This study aims to investigate the antibacterial effectiveness of commonly employed bioactive wound healing compositions with a particular emphasis on their effectiveness against common bacterial pathogens encountered in chronic wounds - Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa to identify optimal wound product composition for managing chronic wound infections.

METHODS

This study tested the antibacterial and antibiofilm effectiveness of four bioactive wound healing materials by performing in vitro antibacterial assays and measuring ion release profiles.

RESULTS

The anti-biofilm effectiveness differed extensively among the biomaterials tested and slightly among the bacterial species. Particularly, copper and zinc-doped borate bioactive glass wound healing compositions inhibited the three clinically relevant bacteria in both planktonic and biofilm forms, which were found to be ascribed to the copper and zinc gradual release.

CONCLUSION

The findings suggest that copper and zinc-doped bioactive glasses hold great promise for improving chronic wound management by providing strong antibacterial action and promoting faster healing.

Carvacrol/cyclodextrin/ceria nanoparticle/hyaluronate hybrid microneedle for promoted diabetic wound healing through the modulation of microenvironment

Delayed healing due to the persistent microenvironment disorder caused by the hyperglycemia and persistent inflammatory reaction is a core pathological characteristic of diabetic wound. Topical microenvironment modulation represents an important avenue to address delayed healing issue. Microneedles are powerful tools for topical microenvironment modulation as they can effectively deliver therapeutic ingredients into the shallow surface layer of the wound based on their depth-limited tissue penetration capability. Herein, a hybrid microneedle composed of carvacrol (CV), cyclodextrin (CD), mesoporous ceria nanoparticles (MCNs) and hyaluronate (HA) is constructed with objective to modulate the microenvironment within the diabetic wound. The hybrid microneedle is constructed via a two-stage process comprising three stepwise embedding procedures in the first stage and four microneedle casting procedures in the second stage. The physical, chemical and antibacterial performances, as well as the in vitro and in vivo therapeutic potentials, of the hybrid microneedle are evaluated. The therapeutic ingredients, mainly CV and MCNs, incorporated in the microneedle can be readily released into the diabetic wound, and effective microenvironment modulation is realized through the designed antibacterial, antioxidant and anti-inflammatory functions. Consequently, the tissue reconstruction processes including cell proliferation and migration, angiogenesis, and collagen deposition are accelerated due to the improved microenvironment.

Co-assembled supramolecular hydrogel of asiaticoside and Panax notoginseng saponins for enhanced wound healing

Self-assembling natural drug hydrogels have emerged as promising biomaterials for scalable and customizable drug delivery systems attributed to their inherent biocompatibility and biodegradability. Asiaticoside (AS), a bioactive compound derived from Centella asiatica (L.) Urb., is known for its antioxidant, antifibrotic, and anti-inflammatory properties, primarily accelerating wound healing through the promotion of collagen synthesis. However, its low water solubility leads to poor transdermal absorption and reduced bioavailability when applied topically. Panax notoginseng saponins (PNS), active compounds derived from the stems of Panax notoginseng (Burk.) F.H. Chen, exhibit amphiphilic and surfactant properties, rendering them effective stabilizers. Our research has demonstrated that the co-assembly of AS and PNS forms a hydrogel, termed AS&PNS hydrogel, which significantly enhances wound healing by reducing interleukin-6 (IL-6) levels and promoting the production of vascular endothelial growth factor (VEGF). Treatment with AS&PNS hydrogel also tended to normalize epidermal thickness and improve collagen fiber organization at the wound site. This novel hydrogel material presents a straightforward and effective approach to managing skin wounds.

Carboxymethyl Chitosan-Based Antioxidant Hydrogel Accelerates Diabetic Wound Healing

Diabetic wound healing is hampered due to oxidative stress, exacerbated inflammation, and impaired angiogenesis in the wounds. A pH-sensitive antioxidant hydrogel based on carboxymethyl chitosan (CMCS), oligoprocyanidins (OPC), and oxide dextran (Oxd) is prepared to accelerate diabetic wound healing. The hydrogel network is formed via imine and hydrogen bonding interactions in the presence of hydroxyl, amino, and aldehyde groups, and deferoxamine (DFO) is incorporated into the hydrogel. The hydrogel shows pH-triggered drug release, a good antioxidant, and anti-inflammatory properties, and can promote tube formation and cell migration in vitro. Moreover, the hydrogel can accelerate wound healing in streptozotocin (STZ)-induced diabetic mice by regulating the inflammation environment with up-regulation of anti-inflammatory factors (IL-4 and IL-10) and down-regulation of pro-inflammatory factors (TNF-α and IL-6), and promoting angiogenesis with up-regulation of HIF-1α, VEGF, and CD31. Thus, the pH-sensitive antioxidant hydrogel provides a promising therapeutic strategy for diabetic wound healing.

Extracellular Vesicles-in-Hydrogel (EViH) targeting pathophysiology for tissue repair

Regenerative medicine endeavors to restore damaged tissues and organs utilizing biological approaches. Utilizing biomaterials to target and regulate the pathophysiological processes of injured tissues stands as a crucial method in propelling this field forward. The Extracellular Vesicles-in-Hydrogel (EViH) system amalgamates the advantages of extracellular vesicles (EVs) and hydrogels, rendering it a prominent biomaterial in regenerative medicine with substantial potential for clinical translation. This review elucidates the development and benefits of the EViH system in tissue regeneration, emphasizing the interaction and impact of EVs and hydrogels. Furthermore, it succinctly outlines the pathophysiological characteristics of various types of tissue injuries such as wounds, bone and cartilage injuries, cardiovascular diseases, nerve injuries, as well as liver and kidney injuries, underscoring how EViH systems target these processes to address related tissue damage. Lastly, it explores the challenges and prospects in further advancing EViH-based tissue regeneration, aiming to impart a comprehensive understanding of EViH. The objective is to furnish a thorough overview of EViH in enhancing regenerative medicine applications and to inspire researchers to devise innovative tissue engineering materials for regenerative medicine.

Recent advances in the role of neuroregulation in skin wound healing

Neuroregulation during skin wound healing involves complex interactions between the nervous system and intricate tissue repair processes. The skin, the largest organ, depends on a complex system of nerves to manage responses to injury. Recent research has emphasized the crucial role of neuroregulation in maximizing wound healing outcomes. Recently, researchers have also explained the interactive contact between the peripheral nervous system and skin cells during the different phases of wound healing. Neurotransmitters and neuropeptides, once observed as simple signalling molecules, have since been recognized as effective regulators of inflammation, angiogenesis, and cell proliferation. The significance of skin innervation and neuromodulators is underscored by the delayed wound healing observed in patients with diabetes and the regenerative capabilities of foetal skin. Foetal skin regeneration is influenced by the neuroregulatory environment, immature immune system, abundant growth factors, and increased pluripotency of cells. Foetal skin cells exhibit greater flexibility and specialized cell types, and the extracellular matrix composition promotes regeneration. The extracellular matrix composition of foetal skin promotes regeneration, making it more capable than adult skin because neuroregulatory signals affect skin regeneration. The understanding of these systems can facilitate the development of therapeutic strategies to alter the nerve supply to the skin to enhance the process of wound healing. Neuroregulation is being explored as a potential therapeutic strategy for enhancing skin wound repair. Bioelectronic strategies and neuromodulation techniques can manipulate neural signalling, optimize the neuroimmune axis, and modulate inflammation. This review describes the function of skin innervation in wound healing, emphasizing the importance of neuropeptides released by sensory and autonomic nerve fibres. This article discusses significant discoveries related to neuroregulation and its impact on skin wound healing.

Co-delivery of antimicrobial peptide and Prussian blue nanoparticles by chitosan/polyvinyl alcohol hydrogels

Altered skin integrity increases the chance of infection, and bacterial infections often lead to a persistent inflammatory response that prolongs healing time. Functional artificial hydrogels are receiving increasing attention as suitable wound dressing barrier. However, the antimicrobial effect of the new dressing still needs to be explored in depth. In this work, the antimicrobial peptide MSI-1 was covalently attached to chitosan-modified poly (vinyl alcohol) hydrogels mixed with Prussian blue nanoparticles (PBNPs) via a primary amine group coupled to a carboxyl group. The synthesized hydrogel has a long-lasting antimicrobial surface and is able to maintain its bactericidal effect on Staphylococcus aureus and Escherichia coli for 24 h. Due to the presence of PBNPs, the hydrogel was able to rise to 48.3 °C within 10 min under near infrared (NIR) light irradiation at a wavelength of 808 nm and maintain this mild temperature to avoid bacterial biofilms. The hydrogel showed >90 % survival in co-culture with cells for 3 d and did not damage major organs in animal experiments. Thus, the photothermal dual-mode antimicrobial hydrogel synthesized in this study increases the selectivity as a safe and efficient wound dressing for the treatment of infected skin defects.

Antimicrobial membranes based on polycaprolactone:pectin blends reinforced with zeolite faujasite for cloxacillin-controlled release

Multifunctional membranes applied to biomedical materials become attractive to support the biological agents and increase their properties. In this study, biopolymeric fibers based on polycaprolactone (PCL) and pectin (PEC) were reinforced with faujasite zeolite (FAU) for cloxacillin antibiotic (CLX) loading. FAU with a high specific surface area (347 ± 8 m2 g-1), high crystallinity and particles with a diameter of up to 100 nm were produced under optimized synthesis conditions (100 °C/4 h). Zeolites were incorporated into polymeric nanofibers to be a cloxacillin (CLX) carrier in wound treatment, using electrospinning as an efficient synthesis method. The fibers produced showed good mechanical resistance and the incorporation of CLX was proven by assays to inhibit the growth of Staphylococcus aureus bacteria. The controlled release of CLX in different pH conditions, which simulate the wound environment, was carried out for up to 229 h, achieving a released CLX concentration of up to 6.18 ± 0.02 mg L-1. These results prove that obtaining a hybrid fiber (polymer-zeolite) to incorporate drugs to be released in a controlled manner was successfully achieved. The bactericidal activity of this material shows that its use for measured applications could be an alternative to conventional methods.

Microneedle patches: a new vantage point for diabetic wound treatments

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

The Effects of Lucilia sericata Larvae and Eisenia fetida Earthworm Extracts Either Alone or in Combination on Healing Third-Degree Burns in Male Mice

Background

Burn as the most common injury disrupts the protective function of the skin and induces complications in patients. Therefore, the treatment of these patients presents a significant clinical challenge. This study evaluated the effects of Lucilia sericata (L. sericata) larvae and Eisenia fetida (E. fetida) earthworm extracts, alone or in combination, on the healing of third-degree burns in male mice.

Materials and Methods

A third-degree burn model was induced on the skin of the interscapular region. Then, the extracts of larvae and earthworms were topically applied separately or simultaneously every other day for a 21-day period. To evaluate the process of wound healing, macroscopic parameters were monitored and examined during the study period. Finally, the animals were sacrificed, and skin sampling was performed for histological investigations.

Results

The results of the study showed that both extracts of larvae and earthworm accelerated the wound-healing process (P < 0.01). The group receiving extract of earthworm had better wound healing than the groups receiving Vaseline and silver sulfadiazine, and histological evidences confirmed these observations. However, the use of two extracts simultaneously did not affect the wound-healing process.

Conclusion

The results of this study demonstrated that the extracts of L. sericata larvae and E. fetida earthworm, especially E. fetida, include effective compounds that can significantly enhance the rate of burn wound healing. However, more studies are needed to identify and purify the effective compounds of these extracts involved in the process of wound healing.

Integrating electrospun aligned fiber scaffolds with bovine serum albumin-basic fibroblast growth factor nanoparticles to promote tendon regeneration

BACKGROUND

Electrospun nanofiber scaffolds have been widely used in tissue engineering because they can mimic extracellular matrix-like structures and offer advantages including high porosity, large specific surface area, and customizable structure. In this study, we prepared scaffolds composed of aligned and random electrospun polycaprolactone (PCL) nanofibers capable of delivering basic fibroblast growth factor (bFGF) in a sustained manner for repairing damaged tendons.

RESULTS

Aligned and random PCL fiber scaffolds containing bFGF-loaded bovine serum albumin (BSA) nanoparticles (BSA-bFGF NPs, diameter 146 ± 32 nm) were fabricated, respectively. To validate the viability of bFGF-loaded aligned PCL nanofiber scaffold (aPCL + bFGF group) in tendon tissue engineering, we assessed the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage and the in vivo regeneration of tendons using a rat Achilles tendon defect model. The encapsulated bFGF could be delivered in a sustained manner in vitro. The aPCL + bFGF scaffold promoted the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage. In the repair of a rat Achilles tendon defect model, the aPCL + bFGF group showed a better repair effect. The scaffold offers a promising substrate for the regeneration of tendon tissue.

CONCLUSIONS

The aligned and random PCL fiber scaffolds containing bFGF nanoparticles were successfully prepared, and their physical and chemical properties were characterized. The aPCL + bFGF scaffold could promote the expression of the related genes and proteins of tendon-forming, facilitating tendon differentiation. In the rat Achilles tendon defect experiments, the aPCL + bFGF exhibited excellent tendon regeneration effects.

Hair Regeneration Methods Using Cells Derived from Human Hair Follicles and Challenges to Overcome

The hair follicle is a complex of mesenchymal and epithelial cells acquiring different properties and characteristics responsible for fulfilling its inductive and regenerative role. The epidermal and dermal crosstalk induces morphogenesis and maintains hair follicle cycling properties. The hair follicle is enriched with pluripotent stem cells, where dermal papilla (DP) cells and dermal sheath (DS) cells constitute the dermal compartment and the epithelial stem cells existing in the bulge region exert their regenerative role by mediating the epithelial-mesenchymal interaction (EMI). Many studies have developed and focused on various methods to optimize the EMI through in vivo and in vitro approaches for hair regeneration. The culturing of human hair mesenchymal cells resulted in the loss of trichogenicity and inductive properties of DP cells, limiting their potential application in de novo hair follicle generation in vivo. Epithelial stem cells derived from human hair follicles are challenging to isolate and culture, making it difficult to obtain enough cells for hair regeneration purposes. Mesenchymal stem cells and epithelial stem cells derived from human hair follicles lose their ability to form hair follicles during culture, limiting the study of hair follicle formation in vivo. Therefore, many attempts and methods have been developed to overcome these limitations. Here, we review the possible and necessary cell methods and techniques used for human hair follicle regeneration and the restoration of hair follicle cell inductivity in culture.

3D-Printed Hydrogel Scaffolds Loaded with Flavanone@ZIF-8 Nanoparticles for Promoting Bacteria-Infected Wound Healing

Bacterial-infected skin wounds caused by trauma remain a significant challenge in modern medicine. Clinically, there is a growing demand for wound dressings with exceptional antibacterial activity and robust regenerative properties. To address the need, this study proposes a novel multifunctional dressing designed to combine efficient gas exchange, effective microbial barriers, and precise drug delivery capabilities, thereby promoting cell proliferation and accelerating wound healing. This work reports the development of a 3D-printed hydrogel scaffold incorporating flavanone (FLA)-loaded ZIF-8 nanoparticles (FLA@ZIF-8 NPs) within a composite matrix of κ-carrageenan (KC) and konjac glucomannan (KGM). The scaffold forms a stable dual-network structure through the chelation of KC with potassium ions and intermolecular hydrogen bonding between KC and KGM. This dual-network structure not only enhances the mechanical stability of the scaffold but also improves its adaptability to complex wound environments. In mildly acidic wound conditions, FLA@ZIF-8 NPs release Zn2+ and flavanone in a controlled manner, providing sustained antibacterial effects and promoting wound healing. In vivo studies using a rat full-thickness infected wound model demonstrated that the FLA@ZIF-8/KC@KGM hydrogel scaffold significantly accelerated wound healing, showcasing its superior performance in the treatment of infected wounds.

Line-field confocal optical coherence tomography coupled with artificial intelligence algorithms as tool to investigate wound healing: A prospective, randomized, single-blinded pilot study

BACKGROUND

Ablative fractional photothermolysis serves as an excellent in vivo model for studying wound healing. The advent of non-invasive imaging devices, such as line-field confocal optical coherence tomography (LC-OCT), enhances this model by enabling detailed monitoring of skin wound healing over time. Additionally, artificial intelligence (AI)-based algorithms are revolutionizing the evaluation of clinical images by providing detailed analyses that are unfeasible manually.

OBJECTIVES

This study aims to assess the value of combining LC-OCT and AI for evaluating the acute wound healing process in the skin.

METHODS

The forearms of participating volunteers were ablated with a CO2 laser in a fractional pattern (7.5 mJ/MTZ) (ClinicalTrials.gov identifier: NCT05614557). To induce observable wound healing differences, two different approved silicone-based formulations were randomly assigned to two test sites, with a third site left untreated. In vivo LC-OCT images were obtained at predefined intervals post-laser treatment, ranging from 1 to 7 days. These images were further analysed using AI algorithms.

RESULTS

LC-OCT visualization allows for the characterization of the structural reorganization of the skin during wound healing. The additional integration of AI algorithms significantly enhances the evaluation of the efficacy of wound care interventions by providing a deeper understanding of how these interventions improve wound healing. This is particularly valuable for primary care providers and dermatologists, as AI algorithms have proven useful in observing, characterizing and understanding keratinocyte behaviour.

CONCLUSIONS

The combination of AI and high-resolution imaging represents a promising tool for better understanding wound healing, evaluating the efficacy of current wound care interventions and analysing keratinocyte behaviour in detail during the wound healing process.

CLINICALTRIALS

GOV IDENTIFIER

NCT05614557.

Programmable Artificial Skins Accomplish Antiscar Healing with Multiple Appendage Regeneration

Functional appendage regeneration is essential for skin rehabilitation, but it has always failed by current existing healing approaches, owing to their inefficacy in preventing disfiguring scars. In this study, a novel regeneration-directing artificial skin (RDAS) system is presented, which is based on the rational design of multi-layered hydrogels that closely mimic natural skin matrices. By leveraging the programmability and architectural rigidity of DNA components, without the need for exogenous cell transplantation, such RDAS effectively minimizes tissue fibrosis by accurately guiding the regenerative process in wound fibroblasts, enabling rapid scarless wound repair, restoration of dermal function, and successful in situ regeneration of multiple appendages, such as hair follicles (HFs), sebaceous glands (SGs), and sweat glands (SwGs). Therefore, the RDAS offers a cell-free antiscarring therapeutic strategy for regenerative wound healing, resulting in improved outcomes. This innovative approach holds great potential for future clinical applications and burn rehabilitation.

3-D bioprinted human-derived skin organoids accelerate full-thickness skin defects repair

The healing of large skin defects remains a significant challenge in clinical settings. The lack of epidermal sources, such as autologous skin grafting, limits full-thickness skin defect repair and leads to excessive scar formation. Skin organoids have the potential to generate a complete skin layer, supporting in-situ skin regeneration in the defect area. In this study, skin organoid spheres, created with human keratinocytes, fibroblasts, and endothelial cells, showed a specific structure with a stromal core surrounded by surface keratinocytes. We selected an appropriate bioink and innovatively combined an extrusion-based bioprinting technique with dual-photo source cross-linking technology to ensure the overall mechanical properties of the 3D bioprinted skin organoid. Moreover, the 3D bioprinted skin organoid was customized to match the size and shape of the wound site, facilitating convenient implantation. When applied to full-thickness skin defects in immunodeficient mice, the 3D bioprinted human-derived skin organoid significantly accelerated wound healing through in-situ regeneration, epithelialization, vascularization, and inhibition of excessive inflammation. The combination of skin organoid and 3D bioprinting technology can overcome the limitations of current skin substitutes, offering a novel treatment strategy to address large-area skin defects.

Dissolvable microneedle-based wound dressing transdermally and continuously delivers anti-inflammatory and pro-angiogenic exosomes for diabetic wound treatment

Due to overactive inflammation and hindered angiogenesis, self-healing of diabetic wounds (DW) remains challenging in the clinic. Platelet-derived exosomes (PLT-Exos), a novel exosome capable of anti-inflammation and pro-angiogenesis, show great potential in DW treatment. However, previous administration of exosomes into skin wounds is topical daub or intradermal injection, which cannot intradermally deliver PLT-Exos into the dermis layer, thus impeding its long-term efficacy in anti-inflammation and pro-angiogenesis. Herein, a dissolvable microneedle-based wound dressing (PLT-Exos@ADMMA-MN) was developed for transdermal and long-term delivery of PLT-Exos. Firstly, a photo-crosslinking methacrylated acellular dermal matrix-based hydrogel (ADMMA-GEL), showing physiochemical tailorability, fast-gelling performance, excellent biocompatibility, and pro-angiogenic capacities, was synthesized as a base material of our dressing. For endowing the dressing with anti-inflammation and pro-angiogenesis, PLT-Exos were encapsulated into ADMMA-GEL with a minimum effective concentration determined by our in-vitro experiments. Then, in-vitro results show that this dressing exhibits excellent properties in anti-inflammation and pro-angiogenesis. Lastly, in-vivo experiments showed that this dressing could continuously and transdermally deliver PLT-Exos into skin wounds to switch local macrophage into M2 phenotype while stimulating neovascularization, thus proving a low-inflammatory and pro-angiogenic microenvironment for DW healing. Collectively, this study provides a novel wound dressing capable of suppressing inflammation and stimulating vascularization for DW treatment.

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.

A Multi-Responsive Hydrogel Combined With Mild Heat Stimulation Promotes Diabetic Wound Healing by Regulating Inflammatory and Enhancing Angiogenesis

The repair of diabetic wound still encounters huge challenges, such as disordered inflammatory regulation and impaired neovascularization. Here, a pH/ROS/glucose responsive and photothermal hydrogel is developed for diabetic wound healing. The hydrogel is formed through cross-linkage between phenylboronic acid-modified carboxymethyl chitosan (CMCS-PBA) and oxide dextran (OXD), utilizing Schiff base and phenylboronate ester bonds. Additionally, insulin-like growth factor 1 C domain (IGF-1C) and deferoxamine-loaded polydopamine nanoparticles (D@P) are incorporated into the hydrogel. The hydrogel demonstrates sustained drug release, excellent photo thermal effect, prominent antioxidant, antibacterial and anti-inflammatory activities, desirable mechanical and tissue adhesive properties, enhanced tube formation, and cell migration. Furthermore, the hydrogel combined with mild heat treatment can regulate chronic inflammation by promoting the transformation of macrophages from M1 phenotype to M2 phenotype and enhance angiogenesis by up-regulating the expression levels of angiogenesis-related factors such as hypoxia-inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF), CD31, and α-SMA, thus greatly accelerates the wound healing in streptozotocin (STZ)-induced diabetic mice. Therefore, this multi-responsive and multifunctional hydrogel holds potential as a therapeutic strategy for diabetic wounds.

Transformation of Natural Resin Resina Draconis to 3D Functionalized Fibrous Scaffolds for Efficient Chronic Wound Healing

Chronic wound healing is a major challenge in clinical practice. Secondary dressing damage and antibiotic resistance are the main obstacles for traditional wound dressings. Resina draconis (RD), a natural resin traditionally used in powder form for wound care, is now considered unsuitable due to the lack of gas permeability and moist environment required for wound healing. Here, RD is incorporated in situ by constructing a 3D coiled fibrous scaffold with polycaprolactone/polyethylene oxide. Due to the high porosity of 3D scaffold, the RD-3D dressings have a favorable swelling capacity, providing permeability and moisture for wound repair. Meanwhile, the transformation of RD powder into 3D dressings fully demonstrates capabilities of RD in rapid hemostasis, bactericidal, and inflammation-regulating activities. In vivo evaluations using pressure ulcer and infected wound models confirm the high efficacy of RD-3D dressing in early wound healing, particularly beneficial in the infected wound model compared to recombinant bovine FGF-basic. Further biological analysis shows that resveratrol, loureirin A, and loureirin B, as potentially bioactive components of RD, individually contribute to different aspects of wound healing. Collectively, RD-3D integrated dressings represent a simple, cost-effective, and safe approach to wound healing, providing an alternative therapy for translating medical dressings from bench to bedside.

Multifunctional carboxymethyl chitosan/oxidized carboxymethyl cellulose hydrogel loaded with ginsenoside Rg1 and polydopamine nanoparticles for infected diabetic wound healing

Besides bacterial infection, diabetic wounds are often accompanied by local inflammatory response, oxidative stress imbalances, and vascular formation disorders, which are the main reasons for long-term non-healing of diabetic wounds. In order to solve this problem, Ch-OCMC-PDA NPs-Rg1 self-healing hydrogel was constructed by Schiff base reaction. With the addition of PDA NPs and Rg1, Ch-OCMC-PDA NPs-Rg1 hydrogel showed excellent physical properties, like compressive strength of 142 kPa, swelling ratio of 148.91 %, and Rg1 carried in the hydrogel could achieve a slow release of 90.59 % within 48 h. What's more, PDA NPs endowed it with highly efficient photothermal antibacterial properties. In addition to excellent biocompatibility, Ch-OCMC-PDA NPs-Rg1 hydrogel could effectively clear intracellular reactive oxygen species, promote macrophages M2 transformation, and facilitate human umbilical vein endothelial cells migration and tube formation. In vivo experiments exhibited that Ch-OCMC-PDA NPs-Rg1 hydrogel could reduce wound inflammation, stimulate early angiogenesis, promote collagen deposition, and shorten the healing process of diabetic infected wounds, and the wound healing rate was significantly increased compared with other groups, reaching 98.41 ± 0.31 %. In summary, the multi-functional dynamic Ch-OCMC-PDA NPs-Rg1 hydrogel provides a new possibility for the treatment of diabetic infection wounds.

Multifunctional Dual Nano-MOF-Modified Decellularized Small Intestinal Submucosa Membrane Accelerates Healing of Infected Wound

The treatment of complex or chronic skin wounds caused by burns, trauma, surgery, and genetic disorders has been a worldwide challenge. Small intestinal submucosa (SIS) is a biological material that is widely used in wound healing. How to further expand the wound healing application of SIS, especially in repairing infected wounds, remains a hot research topic for many tissue engineering and biomaterial scholars focusing on skin regeneration. This study uses nanometal-organic frameworks (nano-MOFs), which have not been applied to modify the SIS membrane before, to construct multifunctional dual nano-MOFs @ SIS membrane (dnMOF@SISm). Nano-MOFs are functionalized onto the nanofiber of SIS via in situ self-assembly under mild reaction conditions without any toxic reagent or complex instruments. The dnMOF@SISm can release Co2+, Zn2+, and bioactive factors, participating in the whole stage of the repair of infected wounds. In vitro, it can regulate the biological activities of various functional cells such as fibroblasts, endothelial cells, and macrophages and shows good antibacterial ability. In the infected full-thickness skin defect rat model, dnMOF@SISm can release metal ions and ligands, killing pathogenic bacteria colonized on the wound surface at the first stage, and then trigger and accelerate the skin repair process via angiogenesis, immune regulation, and collagen deposition. Above all, an efficient, nontoxic, mild self-assembly strategy realizes the functionalization of dual nano-MOFs on the nanofiber of SIS to expand its clinical application scenarios, especially in infected wounds.

Nanoparticle-Based Therapeutics for Enhanced Burn Wound Healing: A Comprehensive Review

Burn wounds pose intricate clinical challenges due to their severity and high risk of complications, demanding advanced therapeutic strategies beyond conventional treatments. This review discusses the application of nanoparticle-based therapies for optimizing burn wound healing. We explore the critical phases of burn wound healing, including inflammation, proliferation, and remodeling, while summarizing key nanoparticle-based strategies that influence these processes to optimize healing. Various nanoparticles, such as metal-based, polymer-based, and extracellular vesicles, are evaluated for their distinctive properties and mechanisms of action, including antimicrobial, anti-inflammatory, and regenerative effects. Future directions are highlighted, focusing on personalized therapies and the integration of sophisticated drug delivery systems, emphasizing the transformative potential of nanoparticles in enhancing burn wound treatment.

A ROS-Responsive Lipid Nanoparticles Release Multifunctional Hydrogel Based on Microenvironment Regulation Promotes Infected Diabetic Wound Healing

The continuous imbalance of the diabetic wound microenvironment is an important cause of chronic nonhealing, which manifests as a vicious cycle between excessive accumulation of reactive oxygen species (ROS) and abnormal healing. Regulating the microenvironment by suppressing wound inflammation, oxidative stress, and bacterial infection is a key challenge in treating diabetic wounds. In this study, ROS-responsive hydrogels are developed composed of silk fibroin methacrylated (SFMA), modified collagen type III (rCol3MA), and lipid nanoparticles (LNPs). The newly designed hydrogel system demonstrated stable physicochemical properties and excellent biocompatibility. Moreover, the release of antimicrobial peptide (AMP) and puerarin (PUE) demonstrated remarkable efficacy in eradicating bacteria, regulating inflammatory responses, and modulating vascular functions. This multifunctional hydrogel is a simple and efficient approach for the treatment of chronic diabetic infected wounds and holds tremendous potential for future clinical applications.

Microneedles based on hyaluronic acid-polyvinyl alcohol with antibacterial, anti-inflammatory, and antioxidant effects promote diabetic wound healing

Diabetic wound healing has become one of the major clinical burdens due to uncontrolled bacterial growth and an increase in the risk of various microbial infections. Despite excellent antioxidant properties, the poor aqueous solubility of resveratrol (RES) hampers its applicability. In this study, we proposed a novel multifunctional microneedle patch loaded with RES-encapsulated polymeric micelles. Resveratrol micelles (RES MC) were loaded in the microneedle tip, while the base part was coated with the antibiotic gentamicin (GEN) to promote wound healing. The microneedle tip composed of sodium hyaluronate (HA) could effectively deliver the anti-inflammatory and antioxidant RES MC. Furthermore, the base of the microneedle patch composed of polyvinyl alcohol (PVA) offered excellent flexibility, releasing GEN and providing resistance to bacterial contamination, thereby further promoting wound repair. In vitro antibacterial experiments indicated that the bactericidal rate reached 99 %. Further, the wound healing rate was recorded as 86.05 % on the 11th day of diabetes wound treatment. Together, the multifunctional microneedle patch with excellent biocompatibility exhibited anti-inflammatory, antioxidant, and antibacterial effects on the wound healing process, potentiating its efficacy in the treatment of diabetic wounds.

Nervonic acid as novel therapeutics initiates both neurogenesis and angiogenesis for comprehensive wound repair and healing

Rapid tissue reconstruction in acute and chronic injuries are challengeable, the inefficient repair mainly due to the difficulty in simultaneous promoting the regeneration of peripheral nerves and vascular, which are closely related. Main clinical medication strategy of tissue repair depends on different cytokines to achieve nerves, blood vessels or granulation tissue regeneration, respectively. However, their effect is still limited to single aspect with biorisk exists upon long-time use. Herein, for the first time, we have demonstrated that NA isolated from Malania oleifera has potential to simultaneously promote both neurogenesis and angiogenesis in vitro and in vivo. First, NA was identified by NMR and FTIR structural characterization analysis. In a model of oxidative stress in neural cells induced by hydrogen peroxide, the cells viability of RSC96 and PC12 were protected from oxidative stress injury by NA. Similarly, based on the rat wound healing model, effective blood vessel formation and wound healing can be observed in tissue staining under NA treatment. In addition, according to the identification of nerve and vascular related markers in the wound tissue, the mechanism of NA promoting nerve regeneration lies in the upregulation of the secretion NGF, NF-200 and S100 protein, and NA treatment was also able to up-regulate VEGF and CD31 to directly promote angiogenesis during wound healing. This study provides an important candidate drug molecules for acute or chronic wound healing and nerve vascular synchronous regeneration.

Silk Composite-Based Multifunctional Pellets for Controlled Release

Chronic wounds present significant clinical challenges due to the high risk of infections and persistent inflammation. While personalized treatments in point-of-care settings are crucial, they are limited by the complex fabrication techniques of the existing products. The calcium sulfate hemihydrate (CSH)-based drug delivery platform enables rapid fabrication but lacks antioxidant and antibacterial properties, essential to promote healing. To develop a multifunctional platform, a tannic acid (TA)-silk fibroin (SF) complex is engineered and incorporated as an additive in CSH cement. This cement is then cast into pellets to create silk/bioceramic-based composite drug delivery systems, designed for point-of-care use. Compared to neat CSH pellets, the composite pellets exhibit a 7.5-fold increase in antioxidant activity and prolonged antibacterial efficacy (up to 13 d). Moreover, the subcutaneous implantation of the pellets shows no hallmarks of local or systemic toxicity in a rodent model. The pellets are optimized in composition and fabrication to ease market translation. Clinically, the pellets have the potential to be further developed into products to place on wound beds or fill into bone cavities that are designed to deliver the intended therapeutic effect. The developed multifunctional system proves to be a promising solution for personalized treatment in point-of-care settings.

Development of hybrid polyvinylpyrrolidone/carboxymethyl cellulose/collagen incorporated oregano scaffolds via direct ink write printing for potential wound healing applications

Additive manufacturing can develop regenerative scaffolds for wound healing. 3D printing offers meticulous porosity, mechanical integrity, cell adhesion and cost-effectiveness. Herein, we prepared ink composed of carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), collagen, and oregano extract for the fabrication of tissue constructs. The blend was optimized to form a homogeneous ink and rheological characterization demonstrated shear thinning behavior. The scaffolds were printed using Direct Ink Write (DIW) at a flow speed of 4 mm3/s and a layer height of 0.18 mm. The fabricated scaffolds demonstrated an ultimate tensile strength (UTS) and toughness of 730 KPa and 2.72 MJ/m3, respectively. Scanning Electron Microscopy (SEM) revealed an average pore size of 300 ± 30 μm. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that all materials were present. The contact angle of the composite scaffold was 68° ± 1°. Moreover, the scaffolds presented 82 % mass loss (degradation) in phosphate buffer saline (PBS) over 14 days. The composite scaffold exhibited inhibition zones of 9 mm and 12 mm against Staphylococcus aureus and Escherichia coli, respectively. The PVP/CMC/collagen/oregano 3D printed scaffolds exhibited excellent biocompatibility with the mesenchymal stem cells and humman dermal fibroblast cells, confirmed by water-soluble tetrazolium - 8 (WST-8) assay (test conducted for 7 days). The enhanced angiogenic potential of said scaffold was assesed by release of vascular endothelial growth factor followed by further validation through in-vivo CAM assay. Thus, confirming suitability for the potential wound healing application.

Experimental protocol for evaluation of biomaterials in an in-vivo silicone implant coverage

PURPOSE

To describe an experimental surgical model in rats using a dual-plane technique for evaluation of biomaterials in an in-vivo silicone implant coverage.

METHODS

This study was developed following the ISO 10993-6 standard. In this study, 40 male Wistar rats weighing between 250 and 350 g were used, distributed into two groups: experimental, biomaterial superimposed on the minimammary prosthesis (MP); and control, MP without implantation of the biomaterial, with eight animals at each biological point: 1, 2, 4, 12, and 26 weeks. Thus, at the end of biological points (1, 2, 4, 12, and 26 weeks; n = 8 animals per week), the tissue specimens achieved were fixed in buffered formalin and stained with hematoxylin-eosin.

RESULTS

Macroscopically, throughout the study, no postoperative complications were apparent. In the histological analysis, it was possible to observe the evolution of the inflammatory response, tissue repair, and fibrous capsule during the biological points.

CONCLUSIONS

The experimental model described in this study proved to be suitable for evaluating the biomaterial used in the coverage of breast silicone implants.