Structural and biological engineering of 3D hydrogels for wound healing

Bioactive multifunctional hydrogels accelerate burn wound healing via M2 macrophage-polarization, antioxidant and anti-inflammatory

Globally, more than 300,000 fatalities occur from burns annually, and burn-wound healing continues to present significant challenges owing to the wound's propensity for infections, heavy bleeding, poor angiogenesis, and persistent inflammatory responses. The immunomodulation of macrophage polarization toward the M2 phenotype facilitates the healing of burn wounds by controlling the tissue microenvironment and expediting the transition from the inflammatory phase to proliferation. Here, a polydopamine-mediated graphene oxide (GA), tannic acid (TA), and magnesium ion (Mg2+)-incorporated multifunctional gelatin (Gel) scaffold (GTMG) is developed to accelerate wound healing by modulating the inflammatory microenvironment of burn wounds. GA and Mg2+ confer the scaffold with the conversion of M1-type to M2-type macrophages and vascular regeneration. TA and GA synergistically provide with antimicrobial capabilities to the hydrogel. Additionally, the multifunctional hydrogel shows strong hemostatic, anti-inflammatory and biocompatible properties. Due to its strong tissue adhesion and injectability, the hydrogel can also be used for various forms of dynamic burn wounds. In vivo research shows that the hydrogel may have hemostatic, anti-inflammatory, and M2-phenotypic macrophage-polarization effects, which increase the regeneration and repair effects of burn sites and shorten the burn-healing time. The results indicate that this multifunctional hydrogel offers a promising therapeutic approach for the treatment of burn wounds by altering the immunological microenvironment and accelerating the three phases of wound healing.

Cytotoxicity evaluation of microbial sophorolipids and glucolipids using normal human dermal fibroblasts (NHDF) in vitro

Fibroblasts are considered a key player in the wound healing process. Although this cellular family is constituted by several distinct subtypes, dermal fibroblasts are crucial thanks to their ability to secrete pro-regenerative growth factors, extracellular matrix (ECM) proteins and their immune and anti-inflammatory role. Sophorolipids (SL), sophorosides (SS) and glucolipids (G), mono-unsaturated (C18:1) or saturated (C18:0), glycolipids derived from microbial fermentation of wild type or engineered yeast Starmerella bombicola, constitute a novel sustainable class of bio-based chemicals with interesting physicochemical characteristics, which allow them to form soft diverse structures from hydrogels to vesicles, micelles or complex coacervates with potential interest in skin regeneration applications. In this study, we first tested the cytocompatibility of a broad set of molecules from this family on normal human dermal fibroblasts (NHDF). Our results show that, up to an upper threshold (0.1 % w/v), the microbial glycolipids (SL-C18:1, G-C18:1, SSbola-C18:1, SL-C18:0 and G-C18:0) under study were able to sustain cell growth. Furthermore, we selected the least cytotoxic glycolipids (SL-C18:1, SSbola-C18:1, SL-C18:0) to study their potential to promote wound healing by measuring the gene expression of several key skin regeneration markers (i.e. collagen, elastin, transforming growth factor β, fibroblast growth factor …) using qPCR. Unfortunately, none of these glycolipids modulated the gene expression of molecules involved in tissue repair. However, this study aims to encourage the community to test this novel class of molecules for novel high-end biomedical applications.

Importance

Biosurfactants prepared by microbial fermentation are natural amphiphiles of growing importance, with the goal of replacing synthetic surfactants in commercial formulations. However, their cytotoxicity profile is still poorly known, especially for new molecules like single-glucose lipids or bolaform sophorolipids. This wants to contribute to all those applications, which could be developed with biosurfactants in contact with the skin (cosmetics, wound healing). We test the cytotoxicity of five structurally-related molecules (C18:1 and C18:0 sophorolipids, C18:1 and C18:0 single-glucose lipids, C18:1 di-sophoroside) against normal human dermal fibroblasts (NHDF) and evaluate the metabolic activity of the least toxic among them. To the best of our knowledge, cytotoxicity of these molecules, and of microbial biosurfactants in general, was never tested against NHDF.

Fabrication of gelatine/fucoidan nanogel-coated silver nanoparticles for the treatment of wound healing therapy and nursing care

Microbial infections and tissue damage by dressing removal are common problems in wound healing. In this study, gelatine/fucoidan nanogel coated with silver nanoparticles (Ag@Gel/Fu) by simple polymerization technique to assess the antibacterial potential Against human infectious pathogens and wound healing activity Against L929 fibroblast cells. The incorporation of silver nanoparticles in Ag@Gel/Fu nanogel was confirmed by UV-vis, XRD, and SEM analysis techniques. The results of the antibacterial assay revealed that the Ag@Gel/Fu nanogel showed excellent bacterial growth reduction and zone of inhibition against Escherichia coli and Staphylococcus aureus, depending upon the concentrations. In vitro wound healing results exhibit rapid regeneration of L929 cells in a short duration. It has more advantages, such as Ag@Gel/Fu, to prevent damage to outer skin tissue by infections. It is the more significant bacterial and biofilm infection control of the wound sites. The overall results confirmed that coating of biopolymer and marine polysaccharide fucoidan enhances the biological property of Ag@Gel/Fu nanogel and wound healing potential. Ag@Gel/Fu nanogel co-culture with fibroblast cells showed no cytotoxic effect after 48 h. Finally, Ag@Gel/Fu nanogel is an effective material for infected wound healing nursing care applications.

Anisotropic structure of nanofiber hydrogel accelerates diabetic wound healing via triadic synergy of immune-angiogenic-neurogenic microenvironments

Wound healing in chronic diabetic patients remains challenging due to the multiple types of cellular dysfunction and the impairment of multidimensional microenvironments. The physical signals of structural anisotropy offer significant potential for orchestrating multicellular regulation through physical contact and cellular mechanosensing pathways, irrespective of cell type. In this study, we developed a highly oriented anisotropic nanofiber hydrogel designed to provide directional guidance for cellular extension and cytoskeletal organization, thereby achieving pronounced multicellular modulation, including shape-induced polarization of macrophages, morphogenetic maturation of Schwann cells, oriented extracellular matrix (ECM) deposition by fibroblasts, and enhanced vascularization by endothelial cells. Additionally, we incorporated a VEGF-mimicking peptide to further reinforce angiogenesis, a pivotal phase that interlocks with immune regulation, neurogenesis, and tissue regeneration, ultimately contributing to optimized inter-microenvironmental crosstalk. In vivo studies validated that the anisotropic bioactive nanofiber hydrogel effectively accelerated diabetic wound healing by harnessing the triadic synergy of the immune-angiogenic-neurogenic microenvironments. Our findings highlight the promising potential of combining physical and bioactive signals for the modulation of various cell types and the refinement of the multidimensional microenvironment, offering a novel strategy for diabetic wound healing.

Cellulose-Based Nanofibers Infused with Biotherapeutics for Enhanced Wound-Healing Applications

Nanofibers fabricated from various materials such as polymers, carbon, and semiconductors have been widely used for wound healing and tissue engineering applications due to their excellent nontoxic, biocompatible, and biodegradable properties. Nanofibers with a diameter in the nanometer range possess a larger surface area per unit mass permitting easier addition of surface functionalities and release of biotherapeutics incorporated compared with conventional polymeric microfibers. Henceforth, nanofibers are a choice for fabricating scaffolds for the management of wound healing. Nanofibrous scaffolds have emerged as a promising method for fabricating wound dressings since they mimic the fibrous dermal extracellular matrix milieu that offers structural support for wound healing and functional signals for guiding tissue regeneration. Cellulose-based nanofibers have gained significant attention among researchers in the fabrication of on-site biodegradable scaffolds fortified with biotherapeutics in the management of wound healing. Cellulose is a linear, stereoregular insoluble polymer built from repeated units of d-glucopyranose linked with 1,4-β glycoside bonds with a complex and multilevel supramolecular architecture. Cellulose is a choice and has been used by various researchers due to its solubility in many solvents and its capacity for self-assembly into nanofibers, facilitating the mimicry of the natural extracellular matrix fibrous architecture and promoting substantial water retention. It is also abundant and demonstrates low immunogenicity in humans due to its nonanimal origins. To this end, cellulose-based nanofibers have been studied for protein delivery, antibacterial activity, and biosensor applications, among others. Taken together, this review delves into an update on cellulose-based nanofibers fused with bioactive compounds that have not been explored considerably in the past few years.

In situ 3D bioprinted GDMA/Prussian blue nanozyme hydrogel with wet adhesion promotes macrophage phenotype modulation and intestinal defect repair

Developing hydrogels with wet-adhesion, immunomodulation and regenerative repair capabilities in intestinal repair remains a formidable challenge. In the present study, the development of an anti-inflammatory, wet-adhesive, decellularized extracellular matrix hydrogel produced using three-dimensional (3D) -printing technology is presented. This hydrogel, which integrates gelatin and dopamine, was demonstrated to display excellent wet-adhesion properties, fully harnessing the outstanding regenerative potential of the decellularized small-intestine matrix. Furthermore, the integration of Prussian Blue nanozymes imparted significant anti-inflammatory and antioxidant properties. Through modulating macrophage polarization, the hydrogel was not only found to enhance tissue repair, but also to substantially mitigate inflammation. In vivo experiments (namely, histopathological analyses using a rat model) demonstrated that this hydrogel was able to effectively enhance tissue regeneration and healing in models of intestinal damage. In conclusion, through the utilization of 3D-printing technology, the present study has shown that the precise manufacturing and customization of the hydrogel to various shapes and sizes of intestinal defects may be executed, thereby providing an innovative strategy for intestinal repair. This advanced hydrogel has therefore been shown to hold significant promise as a bioadhesive for both emergency repair and regenerative therapy.

Interlacing biology and engineering: An introduction to textiles and their application in tissue engineering

Tissue engineering (TE) aims to provide personalized solutions for tissue loss caused by trauma, tumors, or congenital defects. While traditional methods like autologous and homologous tissue transplants face challenges such as donor shortages and risk of donor site morbidity, TE provides a viable alternative using scaffolds, cells, and biologically active molecules. Textiles represent a promising scaffold option for both in-vitro and in-situ TE applications. Textile engineering is a broad field and can be divided into fiber-based textiles and yarn-based textiles. In fiber-based textiles the textile fabric is produced in the same step as the fibers (e.g. non-wovens, electrospun mats and 3D-printed). For yarn-based textiles, yarns are produced from fibers or filaments first and then, a textile fabric is produced (e.g. woven, weft-knitted, warp-knitted and braided fabrics). The selection of textile scaffold technology depends on the target tissue, mechanical requirements, and fabrication methods, with each approach offering distinct advantages. Braided scaffolds, with their high tensile strength, are ideal for load-bearing tissues like tendons and ligaments, while their ability to form stable hollow lumens makes them suitable for vascular applications. Weaving, weft-, and warp-knitting provide tunable structural properties, with warp-knitting offering the greatest design flexibility. Spacer fabrics enable complex 3D architecture, benefiting applications such as skin grafts and multilayered tissues. Electrospinning, though highly effective in mimicking the ECM, is structurally limited. The complex interactions between materials, fiber properties, and textile technologies allows for scaffolds with a wide range of morphological and mechanical characteristics (e.g., tensile strength of woven textiles ranging from 0.64 to 180.4 N/mm2). With in-depth knowledge, textiles can be tailored to obtain specific mechanical properties as accurately as possible and aid the formation of functional tissue. However, as textile structures inherently differ from biological tissues, careful optimization is required to enhance cell behavior, mechanical performance, and clinical applicability. This review is intended for TE experts interested in using textiles as scaffolds and provides a detailed analysis of the available options, their characteristics and known applications. For this, first the major fiber formation methods are introduced, then subsequent used automated textile technologies are presented, highlighting their strengths and limitations. Finally, we analyze how these textile and fiber structures are utilized in TE, organized by the use of textiles in TE across major organ systems, including the nervous, skin, cardiovascular, respiratory, urinary, digestive, and musculoskeletal systems.

Bioactivity and biomedical applications of pomegranate peel extract: a comprehensive review

Pomegranate peel is a by-product generated during the processing of pomegranate (Punica granatum L.) fruit, accounting for approximately 50% of the total mass of the fruit. Although pomegranate peel is usually regarded as waste, it is rich in various bioactive metabolites such as polyphenols, tannins, and flavonoids, demonstrating significant medicinal and nutritional value. In recent years, Pomegranate peel extract (PPE) has shown broad application prospects in the biomedical field due to its multiple effects, including antioxidant, anti-inflammatory, antibacterial, anti-apoptotic properties, and promotion of cell regeneration. This review consolidates the major bioactive metabolites of PPE and explores its applications in biomedical materials, including nanodrug carriers, hydrogels, and tissue engineering scaffolds. By synthesizing the existing literature, we delve into the potential value of PPE in biomedicine, the challenges currently encountered, and the future directions for research. The aim of this review is to provide a scientific basis for optimizing the utilization of PPE and to facilitate its broader application in the biomedical field.

Hydrogel-based dressing for wound healing: A systematic review of clinical trials

BACKGROUND

Chronic wounds pose significant healthcare challenges. Hydrogel-based wound dressings have garnered significant attention in the field of wound care. Furthermore, no severe adverse effect was reported for treatment with hydrogel in wound healing. However, a comprehensive review of their clinical application for enhancing chronic wound healing is lacking.

OBJECTIVES

This systematic review evaluates their clinical effectiveness of hydrogel-based dressing in managing chronic wounds and assesses the evidence supporting their use.

SEARCH METHODS

We searched the following databases PubMed, the Cochrane Library; Web of Science; and ClinicalTrials.gov. from January 2010 to January 2023.

SELECTION CRITERIA

Published clinical trial studies that evaluate the effect of hydrogel-based dressing on chronic wounds.

RESULT

We included 39 studies with 1786 participants (1818 wounds), 1024 of whom (1100 wounds) received hydrogel dressings while 679 patients (725 wounds) used non-hydrogel dressings. This systematic review of clinical research indicates that utilizing hydrogel dressings could potentially reduce the required time (31.17 ± 21.74 days) for wound healing and enhance the percentage of wound closure (63.76 ± 28.97 %).

CONCLUSIONS

This systematic review revealed that hydrogel dressings are effective in treatment of chronic wounds. Nonetheless, there is a necessity for additional long-term trials tailored to specific wound types and patient characteristics.

Advancement of Nanomaterials- and Biomaterials-Based Technologies for Wound Healing and Tissue Regenerative Applications

Patients and healthcare systems face significant social and financial challenges due to the increasing number of individuals with chronic external and internal wounds that fail to heal. The complexity of the healing process remains a serious health concern, despite the effectiveness of conventional wound dressings in promoting healing. Recent advancements in materials science and fabrication techniques have led to the development of innovative dressings that enhance wound healing. To further expedite the healing process, novel approaches such as nanoparticles, 3D-printed wound dressings, and biomolecule-infused dressings have emerged, along with cell-based methods. Additionally, gene therapy technologies are being harnessed to generate stem cell derivatives that are more functional, selective, and responsive than their natural counterparts. This review highlights the significant potential of biomaterials, nanoparticles, 3D bioprinting, and gene- and cell-based therapies in wound healing. However, it also underscores the necessity for further research to address the existing challenges and integrate these strategies into standard clinical practice.

Cellulose nanofiber-reinforced antimicrobial and antioxidant multifunctional hydrogel with self-healing, adhesion for enhanced wound healing

Current conventional wound dressings used for wound healing are often characterized by restricted bioactivity and devoid of multifunctionality resulting in suboptimal treatment and prolonged healing. Despite recent advances, the simultaneous incorporation of excellent flexibility, good mechanical performance, self-healing, bioactivity, and adhesion properties into the dressings without complicating their efficacy while maintaining simple synthesis remains a grand challenge. Herein, we effectively synthesized hybrid hydrogels of cellulose nanofiber (CNF), polyvinyl alcohol (PVA), and curcumin-modified silver nanoparticles (cAg) through a one-step synthesis method based on hydrogen bonds, dynamic boronic ester bonds, and coordinate covalent bonds. A flexible high mechanical strength (tensile stress (231 kPa) and compressive stress (1.23 MPa), self-healing, adhesive, yet highly antioxidant and antimicrobial hydrogel (with improved activity against C. albicans, S. aureus, and E. coli) is successfully obtained. Concentric structure of the micropores endows the hydrogels, good biodegradability, and sustained drug release of silver and curcumin. More remarkably, the designed hydrogel dressings not only significantly enhance cell viability (over 98 %) and cell proliferation but also promote angiogenesis, re-epithelialization, and deposition of collagen, all of which signal wound closure and substantiate the therapeutic effect of CNF/PB/cAg hydrogels in chronic wounds. These findings open up new perspectives for the design of wound healing hydrogels and beyond.

Evaluation of Dermal Wound Healing Potential: Phytochemical Characterization, Anti-Inflammatory, Antioxidant, and Antimicrobial Activities of Euphorbia guyoniana Boiss. & Reut. Latex

This study investigates the wound-healing potential of Euphorbia guyoniana latex (EGL) in male Wistar rats, along with its biochemical composition and biological activities. Phytochemical analysis identified moderate levels of phenolics, flavonoids, and tannins, with HPLC revealing five phenolic compounds. EGL demonstrated strong antioxidant activity in DPPH assays, surpassing ascorbic acid in protecting red blood cells. Its performance in the ß-carotene-linoleic acid assay was robust, though its FRAP assay results were weaker. EGL also exhibited significant anti-inflammatory activity, comparable to Acetylsalicylic acid, and showed antibacterial effects against Listeria innocua. In Vivo, EGL-infused ointments accelerated wound healing, reducing epithelialization periods to 12-16 days, with a higher wound contraction rate compared to controls. The study concludes that EGL, rich in bioactive compounds, holds potential as a promising natural agent for wound healing, owing to its potent antioxidant, anti-inflammatory, and antibacterial properties.

Hydrogel Dressings as Insulin Delivery Systems for Diabetic Wounds

Diabetic wounds are one of the most common and challenging complications of diabetes. Similar to chronic wounds, diabetic wounds are difficult to treat due to prolonged inflammation, a lack of angiogenesis, abnormal differentiation of new scar tissue, and the occurrence of numerous bacterial infections. Moreover, elevated sugar levels in tissues disrupt the healing process by enhancing inflammatory reactions, disrupting signaling pathways, and leading to the production of abnormal biological structures, which contribute to improper cell differentiation. Traditional dressings, such as bandages, gauze, and semi-occlusive foams, are inadequate for diabetic wounds with high exudation; moreover, frequently changing the dressing can cause secondary irritation. Hence, innovative hydrogel dressings are being developed, which, thanks to their soft polymer matrix, provide an ideal substrate for regenerating tissue. Hydrogels also allow for the introduction and controlled release of growth factors, making them a promising solution for treating diabetic wounds. Recently, researchers have focused on insulin, a hormone secreted by the human body to lower blood sugar levels, due to its interesting characteristics, such as supporting anti-inflammatory and proangiogenic processes and stimulating cell migration and proper proliferation. This review discusses the most important aspects of diabetes and diabetic wounds and traditional and innovative treatment methods, particularly hydrogel dressings used as systems for insulin delivery in response to glucose concentration.

Study on Highly Sensitive Capacitive Pressure Sensor Based on Silk Fibroin-Lignin Nanoparticles Hydrogel

Silk fibroin (SF) hydrogel has been proven to have excellent applications in the field of pressure sensors, but its sensing performance still needs improvement. A flexible hydrogel prepared from natural macromolecular materials was developed, and lignin nanoparticles (LNPs) were introduced during the preparation of the SF hydrogel. When LNPs account for 3% of SF, the sensing unit of the SF-LNPs3% hydrogel exhibits high stress sensitivity (1.32 kPa-1), fast response speed (<0.1 s), and superior cycle stability (≥8000 cycles). The sensor can detect human motion information, such as finger bending, elbow bending, and pulse signals. When worn at the vocal cord position, it can detect the peak value of the characteristic signal during the wearer speaks. This work demonstrates that the SF-LNPs3% hydrogel has high sensitivity and shows great potential in the field of pressure sensors.

On-demand imidazolidinyl urea-based tissue-like, self-healable, and antibacterial hydrogels for infectious wound care

Bacterial wound infections are a growing challenge in healthcare, posing severe risks like systemic infection, organ failure, and sepsis, with projections predicting over 10 million deaths annually by 2050. Antibacterial hydrogels, with adaptable extracellular matrix-like features, are emerging as promising solutions for treating infectious wounds. However, the antibacterial properties of most of these hydrogels are largely attributed to extrinsic agents, and their mechanisms of action remain poorly understood. Herein we introduce for the first time, modified imidazolidinyl urea (IU) as the polymeric backbone for developing tissue-like antibacterial hydrogels. As-designed hydrogels behave tissue-like mechanical features, outstanding antifreeze behavior, and rapid self-healing capabilities. Molecular dynamics (MD) simulation and density functional theory (DFT) calculation were employed to well-understand the extent of H-bonding and metal-ligand coordination to finetune hydrogels' properties. In vitro studies suggest good biocompatibility of hydrogels against mouse fibroblasts & human skin, lung, and red blood cells, with potential wound healing capacity. Additionally, the hydrogels exhibit good 3D printability and remarkable antibacterial activity, attributed to concentration dependent ROS generation, oxidative stress induction, and subsequent disruption of bacterial membrane. On top of that, in vitro biofilm studies confirmed that developed hydrogels are effective in preventing biofilm formation. Therefore, these tissue-mimetic hydrogels present a promising and effective platform for accelerating wound healing while simultaneously controlling bacterial infections, offering hope for the future of wound care.

Recent Advances and Challenges in Metal Halide Perovskite Quantum Dot-Embedded Hydrogels for Biomedical Application

Metal halide perovskite quantum dots (MHP QDs), as a kind of fluorescent material, have attracted much attention due to their excellent photoluminescence (PL) quantum yield (QY), narrow full width at half maximum (FWHM), broad absorption, and tunable emission wavelength. However, the instability and biological incompatibility of MHP QDs greatly hinder their application in the field of biomedicine. Hydrogels are three-dimensional polymer networks that are widely used in biomedicine because of their high transparency and excellent biocompatibility. This review not only introduces the latest research progress in improving the mechanical and optical properties of hydrogels/MHP QDs but also combines it with the existing methods for enhancing the stability of MHP QDs in hydrogels, aiming to provide new ideas for researchers in material selection and methods for constructing MHP QD-embedded hydrogels. Finally, their application prospects and future challenges are introduced.

Application of novel strategies in chronic wound management with focusing on pressure ulcers: new perspective

Invading blood cells, extracellular tissue, and soluble mediators all play important roles in the wound-healing process. There is a substantial global burden of disease and mortality attributable to skin defects that do not heal. About 1% to 2% of the population in industrialized nations suffers from chronic wounds that don't heal, despite healthcare breakthroughs; this condition is very costly, costing about $25 billion each year in the US alone. Amputation, infection (affecting as many as 25% of chronic wounds), sepsis, and dermal replacements are all consequences of conventional therapeutic approaches like growth factor therapy and diabetic foot ulcers account for 85% of lower limb amputations. Despite these obstacles, scientists are constantly looking for new ways to speed healing and close wounds. The unique immunomodulatory capabilities and multipotency of mesenchymal stem cells (MSCs) have made them a potential therapeutic choice in tissue engineering and regenerative medicine. Animal models of wound healing have shown that MSCs can speed up the process by as much as 40% through enhancing angiogenesis, modulating inflammation, and promoting fibroblast migration. Clinical trials provide more evidence of their effectiveness; for instance, one RCT found that, after 12 weeks, patients treated with MSCs had a 72% smaller wound size than those in the control group. This review offers a thorough examination of MSCs by combining the latest research with preclinical evidence. Highlighting their potential to transform treatment paradigms, it delves into their biological properties, how they work during regeneration and healing, and therapeutic usefulness in controlling chronic wounds.

Preparation of a chitosan/polyvinyl alcohol-based dual-network hydrogel for use as a potential wound-healing material for the sustainable release of drugs

Treating chronic wounds poses significant challenges in clinical medicine due to bacterial infection, reactive oxygen species (ROS) accumulation, and excessive inflammation. This study aimed to address these issues by developing a wound dressing with antibacterial, antioxidant, and anti-inflammatory properties. Chitosan was functionally modified with acrolein to covalently bind to epigallocatechin gallate (EGCG), enabling a high EGCG load. Subsequently, polyvinyl alcohol (PVA) and EGCG-modified chitosan were crosslinked to prepare a new double-network hydrogel with added cysteine (CSAEC/P50). CSAEC/P50 demonstrated optimal mechanical properties (low swelling rate, high water retention, and optimal flexibility), low hemolysis, high coagulation properties, and antibacterial and antioxidant activities. Cell scratch tests indicated that CSAEC/P50 can promote NIH3T3 cell migration. Immunofluorescence results showed that CSAEC/P50 promoted the transformation of proinflammatory M1 macrophages to anti-inflammatory M2 macrophages. These findings suggest that CSAEC/P50 has significant potential for use in wound dressing applications.

Development of low-molecular-weight polysaccharide-based wound dressings for full-thickness cutaneous wound healing via coacervate formation

The development of polysaccharide-based wound dressings that are easy to prepare, adhere to tissue, adapt to diverse shapes and exhibit tunable mechanical properties holds significant clinical interest. This study introduced a simple spontaneous liquid-liquid phase separation technique employing low-molecular-weight and high polyion concentration of chitosan (CS) and hyaluronic acid (HA) to fabricate CS/HA coacervates. Upon increasing the molecular weight of chitosan from 7 kDa to 250 kDa, a transition in the CS/HA coacervates from liquid-like state to an elastic liquid and eventually to a solid-like state was observed. The resulting CS/HA coacervates demonstrated robust water resistance and adhesion to skin tissue. Notably, the molecular weight of chitosan significantly influenced the mechanical properties and hydration levels of the CS/HA coacervates. Moreover, in vivo studies using a full-thickness cutaneous defect model revealed that the CS/HA coacervates, prepared using 100 kDa chitosan, markedly accelerate wound healing. The coacervates' ease of preparation, wet adhesion, heterogeneous structure, suitability for irregularly shaped wounds, and exceptional wound healing promotion of the coacervates qualify them as an optimal wound dressing.

Lemon Juice-Infused PVA Nanofibers for the Development of Sustainable Antioxidant and Antibacterial Electrospun Hydrogel Biomaterials

Cross-linking bonds adjacent polymer chains into a three-dimensional network. Cross-linked poly(vinyl alcohol) (PVA) turns into a hydrogel, insoluble structure exhibiting outstanding sorption properties. As an electrospinnable polymer, PVA enables the creation of nanofibrous hydrogels resembling biological tissues, thus ideal for nature-inspired platforms. PVA properties are easily adjustable through additives and an appropriate cross-linking method. Drawing inspiration from environmentally safe approaches, this work developed a new "green" method of low-temperature PVA cross-linking. Nanofibers were electrospun from a precursor solution of PVA dissolved in fresh lemon juice, stabilized by heating at 60 °C for 7 days, and thoroughly characterized. The obtained nanoplatform demonstrated long-term stability and enhanced mechanical properties. Its biocompatibility was confirmed, and its antibacterial and health-promoting effects were attributed to lemon juice-rich in vitamin C, a potent antioxidant with anti-inflammatory properties. The developed system has future potential for use in the biomedical engineering field as a dressing accelerating wound healing.

Multiple crosslinked, self-healing, and shape-adaptable hydrogel laden with pain-relieving chitosan@borneol nanoparticles for infected burn wound healing

Rationale: Next-generation wound dressings with multiple biological functions hold promise for addressing the complications and pain associated with burn wounds. Methods: A hydrogel wound dressing loaded with a pain-relieving drug was developed for treating infected burn wounds. Polyvinyl alcohol chemically grafted with gallic acid (PVA-GA), sodium alginate chemically grafted with 3-aminobenzeneboronic acid (SA-PBA), Zn2+, and chitosan-coated borneol nanoparticles with anti-inflammatory and pain-relieving activities were combined to afford a nanoparticle-loaded hydrogel with a PVA-GA/Zn2+/SA-PBA network crosslinked via multiple physicochemical interactions. Results: The developed hydrogel demonstrated adhesiveness, self-healing, shape adaptability, injectability, degradability, conformity to complicated wound surfaces, and other desirable biological functions, including a pH-responsive drug release behavior and antibacterial, antioxidant, anti-inflammatory, and proangiogenic activities. In a murine scald wound model, the hydrogel effectively prevented infection by Staphylococcus aureus and downregulated pain perception (measured using mouse grimace scale scores and hind paw lifting and licking times), thereby accelerating wound healing. Conclusion: This study provides broad prospects for the development of new hydrogel systems that can substantially improve the dynamic management of infected burn wounds.

Tissue adhesive hyaluronan-quercetin (Ago)@halloysite-fungal carboxymethyl chitosan nanocomposite hydrogels for wound dressing applications

This study investigates nanocomposite hydrogels reinforced with hyaluronan-quercetin‑silver nanoparticles intercalated halloysite clay (HAQ-Hal-Ag) for potential application as wound dressings. HAQ-Hal-Ag (at 1, 3, and 5 wt%) was incorporated into a fungal carboxymethyl chitosan (FC)/polyacrylamide (PAM) network (FC-PAM) using methylene bisacrylamide (MBA) as the crosslinker and ammonium persulfate (APS) as the initiator. Various physicochemical analyses were performed to characterize the resulting hydrogels. The compressive strength of the nanocomposite hydrogels exhibited a proportional increase with increasing HAQ-Hal-Ag content, reaching a remarkable 1.04 MPa for hydrogels containing 5 wt% HAQ-Hal-Ag. Additionally, the hydrogels displayed highly porous structures with excellent swelling capacity. Importantly, they exhibited exceptional antibacterial efficacy against Escherichia coli and Staphylococcus aureus. Furthermore, cytotoxicity assays revealed high cell viability and proliferation rates, confirming the biocompatibility of these hydrogels with human dermal fibroblasts. These findings suggest significant promise for the nanocomposite hydrogels as wound dressing materials due to their outstanding biocompatibility, impressive compressive strength, and potent antibacterial activity.

Regenerative medicine: Hydrogels and mesoporous silica nanoparticles

Hydrogels, that are crosslinked polymer networks, can absorb huge quantities of water and/or biological fluids. Their physical properties, such as elasticity and soft tissue, together with their biocompatibility and biodegradability, closely resemble living tissues. The versatility of hydrogels has fuelled their application in various fields, such as agriculture, biomaterials, the food industry, drug delivery, tissue engineering, and regenerative medicine. Their combination with nanoparticles, specifically with Mesoporous Silica Nanoparticles (MSNs), have elevated these composites to the next level, since MSNs could improve the hydrogel mechanical properties, their ability to encapsulate and controlled release great amounts of different therapeutic agents, and their responsiveness to a variety of external and internal stimuli. In this review, the main features of both MSNs and hydrogels are introduced, followed by the discussion of different hydrogels-MSNs structures and an overview of their use in different applications, such as drug delivery technologies and tissue engineering.

3D Printing in Wound Healing: Innovations, Applications, and Future Directions

The field of wound healing faces significant challenges, particularly in the treatment of chronic wounds, which often result in prolonged healing times and complications. Recent advancements in 3D printing technology have provided innovative solutions to these challenges, offering tailored and precise approaches to wound care. This review highlights the role of 3D printing in enhancing wound healing, focusing on its application in creating biocompatible scaffolds, custom wound dressings, and drug delivery systems. By mimicking the extracellular matrix (ECM) and facilitating cell proliferation, 3D-printed biomaterials have the potential to significantly accelerate the healing process. In addition, 3D bioprinting enables the production of functional skin substitutes that can be customized for individual patients. Despite the promise of these technologies, several challenges remain, including the need for improved vascularization, cost concerns, and regulatory hurdles. The future of wound healing lies in the continued integration of 3D printing with emerging technologies such as 4D printing and bioelectronics, providing opportunities for personalized and on-demand therapies. This review explores the current state of 3D printing in wound care, its challenges, and the future potential of these innovative technologies.

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.

Latest advance anti-inflammatory hydrogel wound dressings and traditional Lignosus rhinoceros used for wound healing agents

Wound healing is a physiological process occurring after the onset of a skin lesion aiming to reconstruct the dermal barrier between the external environment and the body. Depending on the nature and duration of the healing process, wounds are classified as acute (e.g., trauma, surgical wounds) and chronic (e.g., diabetic ulcers) wounds. The latter, often affect millions of people globally, take months to heal or not heal non-healing chronic wounds, are typically susceptible to microbial infection, and are a major cause of morbidity. Wounds can be treated with a variety of non-surgical (topical formulations, wound dressings) and surgical (debridement, skin grafts/flaps) methods. Three-dimensional (3D)-(bio) printing and traditional wound dressings are two examples of modern experimental techniques. This review focuses on several types of anti-inflammatory wound dressings, especially focusing on hydrogels and traditional macro-fungi like L. rhinocerotis as agents that promote wound healing. In this study, we introduced novel anti-inflammatory hydrogel dressings and offered innovative methods for application and preparation to aid in the healing. Additionally, we summarize the key elements required for wound healing and discuss our analysis of potential future issues. These findings suggest that L. rhinocerotis and various anti-inflammatory hydrogels can be considered as conventional and alternative macro-fungi for the treatment of non-communicable diseases. We summarized the development of functional hydrogel dressings and traditional Lignosus rhinoceros used for wound healing agents in recent years, as well as the current situation and future trends, in light of their preparation mechanisms and functional effects.

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.

Design and Applications of Supramolecular Peptide Hydrogel as Artificial Extracellular Matrix

Supramolecular peptide hydrogels (SPHs) consist of peptides containing hydrogelators and functional epitopes, which can first self-assemble into nanofibers and then physically entangle together to form dynamic three-dimensional networks. Their porous structures, excellent bioactivity, and high dynamicity, similar to an extracellular matrix (ECM), have great potential in artificial ECM. The properties of the hydrogel are largely dependent on peptides. The noncovalent interactions among hydrogelators drive the formation of assemblies and further transition into hydrogels, while bioactive epitopes modulate cell-cell and cell-ECM interactions. Therefore, SPHs can support cell growth, making them ideal biomaterials for ECM mimics. This Review outlines the classical molecular design of SPHs from hydrogelators to functional epitopes and summarizes the recent advancements of SPHs as artificial ECMs in nervous system repair, wound healing, bone and cartilage regeneration, and organoid culture. This emerging SPH platform could provide an alternative strategy for developing more effective biomaterials for tissue engineering.

A Multifunctional Nanocomposite Hydrogel Delivery System Based on Dual-Loaded Liposomes for Scarless Wound Healing

Increased inflammatory responses and oxidative stress at the wound site following skin trauma impair healing. Furthermore, skin scarring places fibroblasts under severe mechanical stress and aggravates pathological fibrosis. A novel liposomal composite hydrogel is engineered for wound microenvironment remodeling, incorporating dual-loaded liposomes into gelatin methacrylate to create a nanocomposite hydrogel. Notably, tetrahydrocurcumin (THC) and hepatocyte growth factor (HGF) are encapsulated in the hydrophobic and hydrophilic layers of liposomes, respectively. The composite hydrogel maintains porous nanoarchitecture, demonstrating sustainable THC and HGF release and enhanced mechanical properties and biocompatibility. This system effectively promotes cell proliferation and angiogenesis and attenuates apoptosis. It decreases the expression of the inflammatory factors by inhibiting the high-mobility group box /receptor for advanced glycation end product/NF-κB (HMGB1/RAGE/NF-κB)pathway and increases macrophage polarization from M1 to M2 in vitro, effectively controlling inflammatory responses. It exhibits remarkable antioxidant properties by scavenging excess reactive oxygen species and free radicals. Most importantly, it effectively prevents scar formation by restraining the transforming growth factor beta (TGF-β)/Smads pathway that downregulates associated fibrotic factors. It demonstrates strong therapeutic effects against inflammation and fibrosis in a rat skin wound model with biosafety, advancing the development of innovative hydrogel-based therapeutic delivery strategies for clinical scarless wound therapy.

Synthesis and characterization of self-healable supramolecular hydrogel based on carboxymethyl cellulose for biomedical applications

Hydrogels have been widely used in biomedical fields including tissue engineering, drug delivery and cell delivery and 3D cell delivery due to abundant water content in their hydrophilic three-dimensional networks and having soft tissue similar to the human body. In recent years, supramolecular hydrogels (SHG) formed by the inclusion complex between polyethylene glycol (PEG) and macrocycles such as cyclodextrin (CD) have attracted much interest due to their excellent biocompatibility and great potential in biomedical. In this research, a carboxymethyl cellulose (CMC)-based graft copolymer was prepared by using acrylic acid (AA) and maleic anhydride functionalized β-CD (β-CD-MA) as comonomers and ammonium persulfate (APS) as initiator. Then, a self-healable supramolecular hydrogel was synthesized by formation of a host-guest inclusion complex between CMC-g-poly (AA-co-β-CD-MA) as host molecule and cytosine- and guanine-modified PEG as guest molecules. The prepared hydrogel was characterized by Scanning Electron Microscope (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (1H NMR). The thermal stability of hydrogel was also determined by thermal gravimetric (TGA) and differential scanning calorimetry (DSC) methods. In addition, the loading and release profiles of metformin hydrochloride (MH) drug as a model on hydrogel was investigated. The results indicated that the drug release from the hydrogel peaks around 360 min and aligns with the Ritger-Peppas model. The hydrogel's self-healing property was examined at ambient temperature and 37 °C. It showed 70 % healing in 1.5 h and completed recovery after 9 h.

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

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

Fabrication of porcine acellular dermal matrix and oxidized hyaluronic acid conductive composite hydrogels for accelerating skin wound healing under electrical stimulation

Electrical stimulation (ES) of skin wounds can promote cell proliferation, protein synthesis, inflammatory response, and improve neurological function. In this study, the dynamical cross-linked conductive hydrogels have been developed by integration of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) into porcine acellular dermal matrix (PADM) and oxidized hyaluronic acid (OHA) using dopamine-Fe complex (DA@Fe) as cross-linking agent. The as-obtained conductive composite hydrogels have the characteristics of rapid gelation, excellent deformation ability, high water absorption, and suitable degradation rate. Four-point probes resistivity measurement system has been used to test the electrical properties of the as-obtained hydrogels, and showing their conductivity at 0.207-0.322 S/m. In addition, the developed dynamical cross-linked conductive hydrogels exhibit excellent biocompatibility, thereby inducing cells proliferation and migration. In vivo results show that the resultant composite hydrogel can accelerate wound healing with combination of electrical stimulation (ES) by promoting expression of vascular factor (CD31) and decreasing the expression of tumor necrosis factor-α (TNF-α).

Rapidly molded sodium alginate/soy protein adhesive hydrogel with 808-nm laser inhibition of infected wounds

Infected wounds produce pus and heal slowly. To address this issue, we developed a rapid-setting SP/SA@BP-C hydrogel by combining sodium alginate (SA) and soy protein (SP) with black phosphorus (BP) grafted with clarithromycin (Cla) and incorporating Ca2+ for chelation. This hydrogel dressing exhibits excellent photothermal (PT) and photodynamic (PD) bacteriostatic effects without biotoxicity, making it suitable for treating infected wounds. Characterization confirmed its successful fabrication, and the bacteriostatic effect demonstrated over 99 % efficacy through the synergistic effects of PT, PD, and Cla. Cellular studies indicated nontoxicity and a promoting effect on cell proliferation (121.6 %). In the mouse-infected wound model, the hydrogel led to complete healing in 12 days, with good recovery of the skin's superficial dermal layer and appendages. Consequently, SP/SA@BP-C is a natural hydrogel dressing with promising properties.

Hofmeister effect driven dynamic-bond cross-linked dialdehyde xylan hydrogels with rapid response and robust mechanical properties for expanding stent

The biomedical field urgently needs for programmable stent materials with nontoxic, autonomous self-healing, injectability, and suitable mechanical strength, especially self-expanding characteristics. However, such materials are still lacking. Herein, based on gelatin and dialdehyde-functionalized xylan, we synthesized 3D-printable, autonomous, self-healing, and mechanically robust hydrogels with a reversible Schiff base crosslink network. The hydrogels exhibited excellent mechanical properties and automatic healing properties at room temperature. The solid mechanical properties originate from the Schiff base, hydrogen bonding interactions, and xylan nanoparticle reinforcement of the polymer networks. As a proof of concept, the Hofmeister effect enabled the hydrogel to contract in highly concentrated salt solutions. In contrast, the same hydrogel expanded and relaxed in dilute salt solutions (quick response within 10 s), showing ionic stimulus-response and excellent shape memory characteristics, which demonstrated that the prepared hydrogel could be used as self-expanding artificial vascular stents. In particular, good biocompatibility was confirmed by cytotoxicity and compatibility tests, and ex vivo arterial experiments further indicated the feasibility of these artificial vascular scaffolds (the expansion force reached 1.51 N). Combined with its ionic stimuli-responsive shape memory ability, the strong mechanical, self-healing, 3D-printable, and biocompatibility properties make this hydrogel a promising material for artificial stents in various biomedical applications.

Advanced Hybrid Strategies of GelMA Composite Hydrogels in Bone Defect Repair

To date, severe bone defects remain a significant challenge to the quality of life. All clinically used bone grafts have their limitations. Bone tissue engineering offers the promise of novel bone graft substitutes. Various biomaterial scaffolds are fabricated by mimicking the natural bone structure, mechanical properties, and biological properties. Among them, gelatin methacryloyl (GelMA), as a modified natural biomaterial, possesses a controllable chemical network, high cellular stability and viability, good biocompatibility and degradability, and holds the prospect of a wide range of applications. However, because they are hindered by their mechanical properties, degradation rate, and lack of osteogenic activity, GelMA hydrogels need to be combined with other materials to improve the properties of the composites and endow them with the ability for osteogenesis, vascularization, and neurogenesis. In this paper, we systematically review and summarize the research progress of GelMA composite hydrogel scaffolds in the field of bone defect repair, and discuss ways to improve the properties, which will provide ideas for the design and application of bionic bone substitutes.

Integration of Hydrogels and 3D Bioprinting Technologies for Chronic Wound Healing Management

The integration of hydrogel-based bioinks with 3D bioprinting technologies presents an innovative approach to chronic wound management, which is particularly challenging to treat because of its multifactorial nature and high risk of complications. Using precise deposition techniques, 3D bioprinting significantly alters traditional wound care paradigms by enabling the fabrication of patient-specific wound dressings that imitate natural tissue properties. Hydrogels are notably beneficial for these applications because of their abundant water content and mechanical properties, which promote cell viability and pathophysiological processes of wound healing, such as re-epithelialization and angiogenesis. This article reviews key 3D printing technologies and their significance in enhancing the structural and functional outcomes of wound-care solutions. Challenges in bioink viscosity, cell viability, and printability are addressed, along with discussions on the cross-linking and mechanical stability of the constructs. The potential of 3D bioprinting to revolutionize chronic wound management rests on its capacity to generate remedies that expedite healing and minimize infection risks. Nevertheless, further studies and clinical trials are necessary to advance these therapies from laboratory to clinical use.

Silver Nanoparticles in 3D Printing: A New Frontier in Wound Healing

This review examines the convergence of silver nanoparticles (AgNPs), three-dimensional (3D) printing, and wound healing, focusing on significant advancements in these fields. We explore the unique properties of AgNPs, notably their strong antibacterial efficacy and their potential applications in enhancing wound recovery. Furthermore, the review delves into 3D printing technology, discussing its core principles, various materials employed, and recent innovations. The integration of AgNPs into 3D-printed structures for regenerative medicine is analyzed, emphasizing the benefits of this combined approach and identifying the challenges that must be addressed. This comprehensive overview aims to elucidate the current state of the field and to direct future research toward developing more effective solutions for wound healing.

Sodium carboxymethyl cellulose hydrogels containing montmorillonite-NaClO2 for postharvest preservation of Chinese bayberries

Owing to their lack of outer skin, Chinese bayberries are highly susceptible to mechanical damage during picking, which accelerates bacterial invasion and rotting, shortening their shelf life. In this study, montmorillonite (MMT) was used to absorb an aqueous sodium chlorite solution embedded in a carboxymethyl cellulose sodium hydrogel after freeze drying, and the hydrogel was crosslinked by Al3+ ions. Al3+ hydrolyzed to produce H+, creating an acidic environment within the hydrogel and reacting with NaClO2 to slowly release ClO2. We prepared a ClO2 slow-release hydrogel gasket with 0.5 wt% MMT-NaClO2 and investigated its storage effect on postharvest Chinese bayberries. Its inhibition rates against Escherichia coli and Listeria monocytogenes were 98.84% and 98.96%, respectively. The results showed that the gasket preserved the appearance and nutritional properties of the berries. The antibacterial hydrogel reduced hardness loss by 26.57% and ascorbic acid loss by 46.36%. This new storage method could also be applicable to other fruits and vegetables.

Injectable Photothermal PDA/Chitosan/β-Glycerophosphate Thermosensitive Hydrogels for Antibacterial and Wound Healing Promotion

Controlling infections while reducing the use of antibiotics is what doctors as well as researchers are looking for. As innovative smart materials, photothermal materials can achieve localized heating under light excitation for broad-spectrum bacterial inhibition. A polydopamine/chitosan/β-glycerophosphate temperature-sensitive hydrogel with excellent antibacterial ability is synthesized here. Initially, the hydrogel has good biocompatibility. In vitro experiments reveal its noncytotoxic property when cocultured with gingival fibroblasts and nonhemolytic capability. Concurrently, the in vivo biocompatibility is confirmed through liver and kidney blood markers and staining of key organs. Crucially, the hydrogel has excellent photothermal conversion performance, which can realize the photothermal conversion of hydrogel up to 3 mm thickness. When excited by near-infrared light, localized heating is attainable, resulting in clear inhibition impacts on both Staphylococcus aureus and Escherichia coli, with the inhibition rates of 91.22% and 96.69%, respectively. During studies on mice's infected wounds, it is observed that the hydrogel can decrease S. aureus' presence in the affected area when exposed to near-infrared light, and also lessen initial inflammation and apoptosis, hastening tissue healing. These findings provide valuable insights into the design of antibiotic-free novel biomaterials with good potential for clinical applications.

Hydrogels with Antioxidant Microparticles Systems Based on Hyaluronic Acid for Regenerative Wound Healing

This research focuses on the synthesis of hydrogels exhibiting enhanced antioxidant properties derived from hyaluronic acid (HA) and poly(ethylene brassylate-co-squaric acid) (PEBSA), a copolymacrolactone that have the ability to be used in drug delivery applications. Quercetin (Q), a bioflavonoid with strong antioxidant properties, is employed as a bioactive compound. The biomolecule is encapsulated in the polymeric network using different entrapment techniques, including the initial formation of a complex between PEBSA and Q, which is demonstrated through the dynamic light scattering technique. Fourier transform infrared spectroscopy (FT-IR) and rheological studies confirm the formation of the hydrogels, revealing the occurrence of physical interactions between the synthetic polymer and the polysaccharide. Moreover, the hydrogels demonstrate biocompatible properties after direct contact with the HDFa cell line and antioxidant properties, as revealed by DPPH tests.

Lymphangiogenesis: novel strategies to promote cutaneous wound healing

The cutaneous lymphatic system regulates tissue inflammation, fluid balance and immunological responses. Lymphangiogenesis or lymphatic dysfunction may lead to lymphedema, immune deficiency, chronic inflammation etc. Tissue regeneration and healing depend on angiogenesis and lymphangiogenesis during wound healing. Tissue oedema and chronic inflammation can slow wound healing due to impaired lymphangiogenesis or lymphatic dysfunction. For example, impaired lymphangiogenesis or lymphatic dysfunction has been detected in nonhealing wounds such as diabetic ulcers, venous ulcers and bedsores. This review summarizes the structure and function of the cutaneous lymphatic vessel system and lymphangiogenesis in wounds. Furthermore, we review wound lymphangiogenesis processes and remodelling, especially the influence of the inflammatory phase. Finally, we outline how to control lymphangiogenesis to promote wound healing, assess the possibility of targeting lymphangiogenesis as a novel treatment strategy for chronic wounds and provide an analysis of the possible problems that need to be addressed.

Eye of the future: Unlocking the potential utilization of hydrogels in intraocular lenses

Hydrogels are distinguished by their exceptional ability to absorb and retain large volumes of water within their complex three-dimensional polymer networks, which is advantageous for the development of intraocular lenses (IOLs). Their innate hydrophilicity offers an optimal substrate for the fabrication of IOLs that simulate the natural lens' accommodation, thereby reducing irritation and facilitating healing after surgery. The swelling and water retention characteristics of hydrogels contribute to their notable biocompatibility and versatile mechanical properties. However, the clinical application of hydrogels faces challenges, including managing potential adverse postimplantation effects. Rigorous research is essential to ascertain the safety and effectiveness of hydrogels. This review systematically examines the prospects and constraints of hydrogels as innovative materials for IOLs. Our comprehensive analysis examines their inherent properties, various classification strategies, cross-linking processes, and sensitivity to external stimuli. Additionally, we thoroughly evaluate their interactions with ocular tissues, underscoring the potential for hydrogels to be refined into seamless and biologically integrated visual aids. We also discuss the anticipated technological progress and clinical uses of hydrogels in IOL manufacturing. With ongoing technological advancements, the promise of hydrogels is poised to evolve from concept to clinical reality, marking a significant leap forward in ophthalmology characterized by improved patient comfort, enhanced functionality, and reliable safety.

A Multifunctional Herb-Derived Glycopeptide Hydrogel for Chronic Wound Healing

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

Recombinant fibrous protein biomaterials meet skin tissue engineering

Natural biomaterials, particularly fibrous proteins, are extensively utilized in skin tissue engineering. However, their application is impeded by batch-to-batch variance, limited chemical or physical versatility, and environmental concerns. Recent advancements in gene editing and fermentation technology have catalyzed the emergence of recombinant fibrous protein biomaterials, which are gaining traction in skin tissue engineering. The modular and highly customizable nature of recombinant synthesis enables precise control over biomaterial design, facilitating the incorporation of multiple functional motifs. Additionally, recombinant synthesis allows for a transition from animal-derived sources to microbial sources, thereby reducing endotoxin content and rendering recombinant fibrous protein biomaterials more amenable to scalable production and clinical use. In this review, we provide an overview of prevalent recombinant fibrous protein biomaterials (collagens, elastin, silk proteins and their chimeric derivatives) used in skin tissue engineering (STE) and compare them with their animal-derived counterparts. Furthermore, we discuss their applications in STE, along with the associated challenges and future prospects.

Advances of antimicrobial dressings loaded with antimicrobial agents in infected wounds

Wound healing is a complex process that is critical for maintaining the barrier function of the skin. However, when a large quantity of microorganisms invade damaged skin for an extended period, they can cause local and systemic inflammatory responses. If left untreated, this condition may lead to chronic infected wounds. Infected wounds significantly escalate wound management costs worldwide and impose a substantial burden on patients and healthcare systems. Recent clinical trial results suggest that the utilization of effective antimicrobial wound dressing could represent the simplest and most cost-effective strategy for treating infected wounds, but there has hitherto been no comprehensive evaluation reported on the efficacy of antimicrobial wound dressings in promoting wound healing. Therefore, this review aims to systematically summarize the various types of antimicrobial wound dressings and the current research on antimicrobial agents, thereby providing new insights for the innovative treatment of infected wounds.

Multifunctional Molybdenum-Based Nanoclusters Engineered Gelatin Methacryloyl as In Situ Photo-Cross-Linkable Hybrid Hydrogel Dressings for Enhanced Wound Healing

Skin injuries and wounds present significant clinical challenges, necessitating the development of advanced wound dressings for efficient wound healing and tissue regeneration. In this context, the advancement of hydrogels capable of counteracting the adverse effects arising from undesirable reactive oxygen species (ROS) is of significant importance. This study introduces a hybrid hydrogel with rapid photocuring and excellent conformability, tailored to ameliorate the hostile microenvironment of damaged skin tissues. The hybrid hydrogel, composed of photoresponsive Gelatin Methacryloyl (GelMA) and Molybdenum-based nanoclusters (MNC), exhibits physicochemical characteristics conductive to skin regeneration. In vitro studies demonstrated the cytocompatibility and ROS-responsive behavior of the MNC/GelMA hybrid hydrogels, confirming their ability to promote human dermal fibroblasts (HDF) functions. The incorporation of MNC into GelMA not only enhances HDF adhesion, proliferation, and migration but also shields against oxidative damage induced by hydrogen peroxide (H2O2). Notably, in vivo evaluation in murine full-thickness skin defects revealed that the application of hybrid hydrogel dressings led to reduced inflammation, accelerated wound closure, and enhanced collagen deposition in comparison to control groups. Significantly, this study introduced a convenient approach to develop in situ ROS-scavenging hydrogel dressings to accelerate the wound healing process without the need for exogenous cytokines or medications. We consider that the nanoengineering approach proposed herein offers potential possibilities for the development of therapeutic hydrogel dressings addressing various skin-related conditions.

Multifunctional hydrogel-based engineered extracellular vesicles delivery for complicated wound healing

The utilization of extracellular vesicles (EVs) in wound healing has been well-documented. However, the direct administration of free EVs via subcutaneous injection at wound sites may result in the rapid dissipation of bioactive components and diminished therapeutic efficacy. Functionalized hydrogels provide effective protection, as well as ensure the sustained release and bioactivity of EVs during the wound healing process, making them an ideal candidate material for delivering EVs. In this review, we introduce the mechanisms by which EVs accelerate wound healing, and then elaborate on the construction strategies for engineered EVs. Subsequently, we discuss the synthesis strategies and application of hydrogels as delivery systems for the sustained release of EVs to enhance complicated wound healing. Furthermore, in the face of complicated wounds, functionalized hydrogels with specific wound microenvironment regulation capabilities, such as antimicrobial, anti-inflammatory, and immune regulation, used for loading engineered EVs, provide potential approaches to addressing these healing challenges. Ultimately, we deliberate on potential future trajectories and outlooks, offering a fresh viewpoint on the advancement of artificial intelligence (AI)-energized materials and 3D bio-printed multifunctional hydrogel-based engineered EVs delivery dressings for biomedical applications.

Exploring the mechanistic role of silk sericin biological and chemical conjugates for effective acute and chronic wound repair and related complications

OBJECTIVE

The current review is designed to elaborate and reveal the underlying mechanism of sericin and its conjugates of drug delivery during wounds and wound-related issues.

SIGNIFICANCE

Wound healing is a combination of different humoral, molecular, and cellular mechanisms. Various natural products exhibit potential in wound healing but among them, sericin, catches much attention of researchers due to its bio-functional properties such as being biodegradable, biocompatible, anti-oxidant, anti-bacterial, photo-protector, anti-inflammatory and moisturizing agent.

METHODS AND RESULTS

Sericin triggers the activity of anti-inflammatory cytokines which decrease cell adhesion and promote epithelial cell formation. Moreover, sericin enhances the anti-oxidant enzymes in the wounded area which scavenge the toxic consequences of reactive species (ROS).

CONCLUSIONS

This article highlights the mechanisms of how topical administration of sericin formulations along with 4-hexylresorcinol,\Chitosan\Ag@MOF-GO, polyvinyl alcohol (PVA), platelet lysate and UV photo cross-linked hydrogel sericin methacrylate which recruits a large number of cytokines on wounded area that stimulate fibroblasts and keratinocyte production as well as collagen deposition that led to early wound contraction. It also reviews the different sericin-based nanoparticles that play a significant role in rapid wound healing.

A nano-composite hyaluronic acid-based hydrogel efficiently antibacterial and scavenges ROS for promoting infected diabetic wound healing

Diabetic wound infection brings chronic pain to patients and the therapy remains a crucial challenge owing to the disruption of the internal microenvironment. Herein, we report a nano-composite hydrogel (ZnO@HN) based on ZnO nanoparticles and a photo-trigging hyaluronic acid which is modified by o-nitrobenzene (NB), to accelerate infected diabetic wound healing. The diameter of the prepared ZnO nanoparticle is about 50 nm. X-ray photoelectron spectroscopy (XPS) analysis reveals that the coordinate bond binds ZnO in the hydrogel, rather than simple physical restraint. ZnO@HN possesses efficient antioxidant capacity and it can scavenge DPPH about 40 % in 2 h and inhibit H2O2 >50 % in 8 h. The nano-composite hydrogel also exhibits satisfactory antibacterial capacity (58.35 % against E. coli and 64.03 % against S. aureus for 6 h). In vitro tests suggest that ZnO@HN is biocompatible and promotes cell proliferation. In vivo experiments reveal that the hydrogel can accelerate the formation of new blood vessels and hair follicles. Histological analysis exhibits decreased macrophages, increased myofibroblasts, downregulated TNF-α expression, and enhanced VEGFA expression during wound healing. In conclusion, ZnO@HN could be a promising candidate for treating intractable infected diabetic skin defection.

Continuous and Controllable Preparation of Sodium Alginate Hydrogel Tubes Guided by the Soft Cap Inspired by the Apical Growth of the Plant

Hydrogel tubes made of sodium alginate (SA) have potential applications in drug delivery, soft robots, biomimetic blood vessels, tissue stents, and other fields. However, the continuous preparation of hollow SA hydrogel tubes with good stability and size control remains a huge challenge for chemists, material scientists, and medical practitioners. Inspired by the plant apical growth strategy, a new method named soft cap-guided growth was proposed to produce SA hydrogel tubes. Due to the introduction of inert low gravity substances, such as air and heptane, into the extrusion needle in front of calcium chloride solution to form a soft cap, the SA hydrogel tubes with controllable sizes were fabricated rapidly and continuously without using a template through a negative gravitropism mechanism. The SA hydrogel tubes had good tensile strength, high burst pressure, and good cell compatibility. In addition, hydrogel tubes with complex patterns were conveniently created by controlling the motion path of a soft cap, such as a rotating SA bath or magnetic force. Our research provided a simple innovative technique to steer the growth of hydrogel tubes, which made it possible to mass produce hydrogel tubes with controllable sizes and programmable patterns.