Functional Hydrogels for Treatment of Chronic Wounds

Injectable hydrogels for treating skin injuries in diabetic animal models: a systematic review

Purpose

One of the main causes of chronic wounds is diabetes mellitus (DM), a metabolic disease characterized by chronic hyperglycemia. In this context, hydrogels have been used as a promising treatment for stimulating tissue ingrowth and healing in these injuries. This systematic review aimed to evaluate the findings of studies that investigated the effects of injectable hydrogels of various origins on skin wound healing using in vivo experimental models in diabetic rats.

Methods

This review was conducted in March 2023 using two databases, PubMed and Scopus, following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines and the SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation). The following Medical Subject Headings (MeSH) descriptors were used: "hydrogels," "injectable," "in vivo," "diabetes mellitus," and "skin wound dressing."

Results

After the eligibility assessment, 12 studies were selected and analyzed from an initial 95 articles identified across databases. The studies demonstrated that a variety of injectable hydrogels showed biocompatibility and bioactivity, effectively interacting with skin tissue in diabetic wound models. These hydrogels were assessed for their compositions, structural properties, and in vivo effects on wound closure, inflammation reduction, and collagen deposition. Also, immunofluorescence analyses revealed increased expression of neoangiogenesis markers and reduced inflammatory factors in treated groups, highlighting the hydrogels potential for enhancing skin healing in diabetic wounds.

Conclusion

Injectable hydrogels show significant potential as an effective treatment for diabetic skin wounds, though further clinical studies are needed to fully assess their biological performance.

Biomimetic gradient hydrogel with fibroblast spheroids for full-thickness skin regeneration

Hydrogel-based scaffolds have been widely investigated for their use in tissue engineering to accelerate tissue regeneration. However, replicating the physiological microenvironments of tissues with appropriate biological cues remains challenging. Recent advances in gradient hydrogels have transformed tissue-engineering research by providing precise structures that mimic the extracellular matrix of natural tissues. Unlike conventional homogeneously structured hydrogels, gradient hydrogels provide a better bio-mimicking microenvironment for combined cell therapies in chronic wound treatment by regulating various cell behaviors, such as proliferation, migration, and differentiation. Here, we present the integration of L929 mouse fibroblast spheroids into gradient hydrogels to mimic the dermal stiffness microenvironment and we investigated their impact on full-thickness skin regeneration. A stiffness gradient was achieved by modulating the concentration of methacrylated hyaluronic acid (HA-MA) with varying degrees of methacrylation, using a dual-syringe pump system. The encapsulation of L929 spheroids with gradient hydrogel facilitated skin cell organization in a hierarchically ordered configuration, leading to full-thickness wound healing that was 1.53 times faster than the untreated group in a rat model. This study provides a method for investigating the potential role of gradient hydrogels in various tissue engineering and regeneration applications.

Enhancing burn wound care with pre-crosslinked 3D-printed patches: Bromelain delivery and aloe vera bioactives integration for improved healing outcomes

Burn wounds remain a major clinical challenge due to the limitations of traditional dressings, which often fail to address the diverse needs of patients and varying wound types. This study aimed to advance burn care by developing a 3D-printed patch incorporating natural bioactive compounds from bromelain and aloe vera. The patch was formulated using pre-crosslinked chitosan and alginate hydrogels to ensure suitability for 3D printing and subsequent use. Rheological analysis revealed weak gel behaviour and shear-thinning properties, ensuring excellent printability. The patches exhibited outstanding swelling behaviour and controlled degradation (30 %), alongside notable antioxidant and anti-inflammatory potential, with a polyphenolic content of 1.43 ± 0.07 mg CAE/g and effective scavenging of DPPH, ABTS, and NO radicals, with IC50 values of 29.51 ± 0.30, 10.31 ± 0.28, and 5.94 ± 0.42 mg/mL, respectively. Bioactive compounds from bromelain were consistently released across various pH levels, supporting their therapeutic efficacy. Cell viability studies confirmed strong support for cell growth, while in vitro scratch tests demonstrated biocompatibility and promotion of wound closure. Histological analysis of ex vivo burn models revealed cellular necrosis and protein denaturation characteristic of burn wounds. Application of the patches significantly improved epidermal morphology and enhanced proliferation markers such as Ki67 and α-SMA, indicative of accelerated wound healing. While further clinical validation is needed, these findings underscore the potential of the 3D-printed patches as an innovative solution for burn wound care, offering improved bioactive delivery and enhanced healing outcomes compared to conventional dressings.

Biomimetic Hydrogels - Tools for Regenerative Medicine, Oncology, and Understanding Medical Gas Plasma Therapy

Biomimetic hydrogels enable biochemical, cell biology, and tissue-like studies in the third dimension. Smart hydrogels are also frequently used in tissue engineering and as drug carriers for intra- or extracutaneous regenerative medicine. They have also been studied in bio-sensor development, 3D cell culture, and organoid growth optimization. Yet, many hydrogel types, adjuvant components, and cross-linking methods have emerged over decades, diversifying and complexifying such studies. Here, an evaluative overview is provided, mapping potential applications to the corresponding hydrogel tuning. Strikingly, hydrogels are ideal for studying locoregional therapy modalities, such as cold medical gas plasma technology. These partially ionized gases produce various reactive oxygen species (ROS) types along with other physico-chemical components such as ions and electric fields, and the spatio-temporal effects of these components delivered to diseased tissues remain largely elusive to date. Hence, this work outlines the promising applications of hydrogels in biomedical research in general and cold plasma science in particular and underlines the great potential of these smart scaffolds for current and future research and therapy.

Honey, Gellan Gum, and Hyaluronic Acid as Therapeutic Approaches for Skin Regeneration

Background/Objectives: Chronic wounds pose a significant health concern, with their prevalence increasing due to various etiologies. The global aging population further contributes to this rise, placing a substantial burden on healthcare systems in developed countries. This work aimed to develop new therapeutic options in the form of creams and dressings based on honey, gellan gum, and hyaluronic acid for preventing and treating chronic wounds across all stages. Methods: To address this, after the formulations were developed, in vitro cytocompatibility was determined. To confirm biocompatibility, an ovine wound model was used: full-thickness excisional wounds were treated with three formulations, namely gellan gum and honey sponges (GG-HNY), gellan gum, honey and hyaluronic acid sponges (GG-HA-HNY) and a honey-based cream (cream FB002). Daily assessments, including visual evaluation and wound scoring, were conducted for 30 days. Following the study period, tissues were collected for histological analyses. Results: The macroscopic examination revealed that all therapeutic groups facilitated lesion closure. Lesion size reduction, granulation tissue disappearance, and scar tissue development were consistent across all groups, with the group receiving cream demonstrating an advanced stage of healing. All groups achieved substantial wound closure by day 30, with no significant differences. Histopathological analysis following ISO standards revealed that GG-HA-HNY had the lowest ISO score, indicating minimal reactivity and inflammation, which corroborated the cytocompatibility. Conclusions: Combining these insights with previous findings enhances our understanding of wound regeneration dynamics and contributes to refining therapeutic strategies for chronic wounds. The formulations were designed to balance therapeutic efficacy with cost-effectiveness, leveraging low-cost raw materials and straightforward production methods.

Horseradish peroxidase/hydrogen peroxide-driven photothermally enhanced hydrogel loaded with black rice extract for treating infected skin wound

Bacterial infection of the damaged skin area hinders the wound healing process. Photothermal antibacterial therapy has attracted increasing attention. As green, safe, and possessing various bioactive properties, natural plant extracts are a good choice. However, few natural plant extracts exhibit excellent photothermal responsiveness in the near-infrared range, requiring increased concentration and radiation power to achieve satisfactory photothermal therapeutic effects. In this study, the horseradish peroxidase/hydrogen peroxide (HRP/H2O2) catalytic system was used to simultaneously oxidize anthocyanin-rich black rice extract (BRE) and hyaluronic acid-tyramine conjugate (HT), obtaining a hydrogel based on modified hyaluronic acid with enhanced photothermal ability, abbreviated as HTB. Compared to the sole HT hydrogel, the introduction and oxidation of BRE bring in the near infrared ray-responsive photothermal ability of HTB hydrogel. As a result, a lower amount of black rice extract (3 mg/mL) and reduced NIR power density (0.8 mW/cm2) are required to achieve effective photothermal therapy, further improving the hydrogel's antibacterial activity. Besides, the adhesive, coagulant, antioxidant, and anti-inflammatory properties of HTB hydrogel were also promoted. In an infected wound model in mice, the HTB hydrogel combined with photothermal treatment significantly increased CD206 expression while suppressing CD86 expression at the wound site, indicating its bactericidal and anti-inflammatory effects. Additionally, elevated levels of CD31 and α-SMA expression in the wound tissue suggest that the photothermal hydrogel dressing promotes angiogenesis. Therefore, this enzyme-crosslinked HTB hydrogel demonstrates strong photothermal antibacterial activity as well as good anti-inflammatory and pro-angiogenic effects and holds promising potential for application in treating infected wounds.

Bioderived Green Algae Metabolite as a Latent Cross-Linking Agent for Protein-Based Hydrogels with High Potential for Skin Repair Applications

Despite advances in wound treatment through tissue engineering, the rapid colonization of biomaterials by host cells remains a crucial step toward complete wound healing. Thanks to their excellent biocompatibility, biodegradability, low antigenicity and cost-effectiveness, cross-linked hydrogels have attracted much attention as a viable solution for wound treatment. In this work, we have developed an inovative cross-linking method for gelatin-based hydrogels inspired by the wound closure mechanism of the green algae Caulerpa taxifolia. Caulerpenyne (CYN), a metabolite extracted from the algae, was used as a latent cross-linking agent for gelatin. The covalent cross-linking process is triggered by an in situ and on-demand deacetylation of the enol acetate functionalities of CYN in oxytoxin 2 (OXY) containing 1,4-dialdehyde, which immediately reacts with the lysine residue in gelatin. The content of ε-amino groups in gelatin was monitored as a function of CYN concentration. Swelling and gel content were analyzed as a function of CYN concentration. Morphology, rheological and biological properties were evaluated by in vitro and in vivo tests. Cell adhesion and viability tests performed with OXY-cross-linked hydrogels and compared with non-cross-linked and genipin-cross-linked gelatin showed excellent performance. Their use in whole skin wounds in pigs showed that CYN-cross-linked hydrogels promoted complete skin regeneration without any cytotoxicity, making them extremely promising matrices in the field of regenerative medicine.

Advancements in Wound Dressing Materials: Highlighting Recent Progress in Hydrogels, Foams, and Antimicrobial Dressings

Recent advancements in wound dressing materials have significantly improved acute and chronic wound management by addressing challenges such as infection control, moisture balance, and enhanced healing. Important progress has been made, especially with hydrogels, foams, and antimicrobial materials for creating optimized dressings. Hydrogels are known for maintaining optimal moisture levels, while foam dressings are excellent exudate absorbents. Meanwhile, antimicrobial dressing incorporates various antimicrobial agents to reduce infection risks. These dressing options reduce wound healing time while focusing on customized patient needs. Therefore, this review highlights the newest research materials and prototypes for wound healing applications, emphasizing their particular benefits and clinical importance. Innovations such as stimuli-responsive hydrogels and hybrid bioengineered composites are discussed in relation to their enhanced properties, including responsiveness to pH, temperature, glucose, or enzymes and drug delivery precision. Moreover, ongoing clinical trials have been included, demonstrating the potential of emerging solutions to be soon translated from the laboratory to clinical settings. By discussing interdisciplinary approaches that integrate advanced materials, nanotechnology, and biological insights, this work provides a contemporary framework for patient-centric, efficient wound care strategies.

New Perspectives of Hydrogels in Chronic Wound Management

Chronic wounds pose a substantial healthcare concern due to their prevalence and cost burden. This paper presents a detailed overview of chronic wounds and emphasizes the critical need for novel therapeutic solutions. The pathophysiology of wound healing is discussed, including the healing stages and the factors contributing to chronicity. The focus is on diverse types of chronic wounds, such as diabetic foot necrosis, pressure ulcers, and venous leg ulcers, highlighting their etiology, consequences, and the therapeutic issues they provide. Further, modern wound care solutions, particularly hydrogels, are highlighted for tackling the challenges of chronic wound management. Hydrogels are characterized as multipurpose materials that possess vital characteristics like the capacity to retain moisture, biocompatibility, and the incorporation of active drugs. Hydrogels' effectiveness in therapeutic applications is demonstrated by how they support healing, including preserving ideal moisture levels, promoting cellular migration, and possessing antibacterial properties. Thus, this paper presents hydrogel technology's latest developments, emphasizing drug-loaded and stimuli-responsive types and underscoring how these advanced formulations greatly improve therapy outcomes by enabling dynamic and focused reactions to the wound environment. Future directions for hydrogel research promote the development of customized hydrogel treatments and the incorporation of digital health tools to improve the treatment of chronic wounds.

Naturally derived hydrogels for wound healing

Natural hydrogels have garnered increasing attention due to their natural origins and beneficial roles in wound healing. Hydrogel water-retaining capacity and excellent biocompatibility create an ideal moist environment for wound healing, thereby enhancing cell proliferation and tissue regeneration. For this reason, naturally derived hydrogels formulated from biomaterials such as chitosan, alginate, gelatin, and fibroin are highly promising due to their biodegradability and low immunogenic responses. Recent integrated approaches to utilizing new technologies with bioactive agents have significantly improved the mechanical properties of hydrogels and the controlled release and delivery of active compounds, thereby increasing the efficiency of the treatment processes. Herein, this review highlights the advantages and the challenges of natural hydrogels in wound healing, focusing on their mechanical strength, controlled degradation rates, safety and efficiency validation, and the potential for incorporating advanced technologies such as tissue engineering and gene therapy for utilization in personalized medicine.

Films Based on Chitosan/Konjac Glucomannan Blend Containing Resveratrol for Potential Skin Application

Biopolymers represent a significant class of materials with potential applications in skin care due to their beneficial properties. Resveratrol is a natural substance that exhibits a range of biological activities, including the scavenging of free radicals and anti-inflammatory and anti-aging effects. In this study, chitosan/konjac glucomannan resveratrol-enriched thin films were prepared. The enrichment of biomaterials with active ingredients is a common practice, as it allows the desired properties to be obtained in the final product. To characterize the films, several analyses were performed, including infrared spectroscopy, imaging of the samples by SEM and AFM techniques, swelling analysis in pH 5.5 and 7.4, mechanical and antioxidant assays, contact angle measurements, and determination of the resveratrol release profile under the skin mimicking conditions. Resveratrol incorporation into the matrices resulted in modifications to the chemical structure and film morphology. The mechanical characteristics of films with additives were found to undergo deterioration. The sample containing 10% of resveratrol exhibited a higher swelling degree than other films. The resveratrol-modified films demonstrated a notable antioxidant capacity, a reduced contact angle, and enhanced wettability. The resveratrol release occurred rapidly initially, with a maximum of 84% and 56% of the substance released depending on the sample type. Thus, the proposed formulations have promising properties, in particular good swelling capacity, high antioxidant potential, and improved wettability, and may serve as skin dressings after further investigation.

Current Insight of Peptide-Based Hydrogels for Chronic Wound Healing Applications: A Concise Review

Chronic wounds present a substantial healthcare obstacle, marked by an extended healing period that can persist for weeks, months, or even years. Typically, they do not progress through the usual phases of healing, which include hemostasis, inflammation, proliferation, and remodeling, within the expected timeframe. Therefore, to address the socioeconomic burden in taking care of chronic wounds, hydrogel-based therapeutic materials have been proposed. Hydrogels are hydrophilic polymer networks with a 3D structure which allows them to become skin substitutes for chronic wounds. Knowing that peptides are abundant in the human body and possess distinct biological functionality, activity, and selectivity, their adaptability as peptide-based hydrogels to individual therapeutic requirements has made them a significant potential biomaterial for the treatment of chronic wounds. Peptide-based hydrogels possess excellent physicochemical and mechanical characteristics such as biodegradability and swelling, and suitable rheological properties as well great biocompatibility. Moreover, they interact with cells, promoting adhesion, migration, and proliferation. These characteristics and cellular interactions have driven peptide-based hydrogels to be applied in chronic wound healing.

Investigation of Chitosan-Based Hydrogels and Polycaprolactone-Based Electrospun Fibers as Wound Dressing Materials Based on Mechanical, Physical, and Chemical Characterization

The aim of this project is to fabricate fiber mats and hydrogel materials that constitute the two main components of a wound dressing material. The contributions of boric acid (BA) and zinc oxide (ZnO) to the physical and mechanical properties of polycaprolactone (PCL) is investigated. These materials are chosen for their antimicrobial and antifungal effects. Additionally, since chitosan forms brittle hydrogels, it is reinforced with polyvinyl alcohol (PVA) to improve ductility and water uptake properties. For these purposes, PCL, BA, ZnO, PVA, and chitosan are used in different ratios to fabricate nanofiber mats and hydrogels. Mechanical, physical, and chemical characteristics are examined. The highest elastic modulus and tensile strength are obtained from samples with 6% BA and 10% ZnO concentrations. ZnO-decorated fibers exhibit a higher elastic modulus than those with BA, though BA-containing fibers exhibit greater elongation before breakage. All fibers exhibit hydrophobic properties, which help to prevent biofilm formation. In compression tests, CS12 demonstrates the highest strength. Increasing the PVA content enhances ductility, while a higher concentration of chitosan results in a denser structure. This outcome is confirmed by FTIR and swelling tests. These findings highlight the optimal combinations of nanofibrous mats and hydrogels, offering guidance for future wound dressing designs that balance mechanical strength, water absorption, and antimicrobial properties. By stacking these nanofibrous mats and hydrogels in different orders, it is expected to achieve a wound care material that is suitable for various applications. The authors encourage experimentation with different configurations of these nanofiber and hydrogel stackings to observe their mechanical behavior under real-life conditions in future studies.

An injectable hydrogel of porcine cholecyst extracellular matrix for accelerated wound healing

Hydrogel formulations of xenogeneic extracellular matrices have been widely used for topical wound care because of their exceptional tunability over other formulations like lyophilized sheets, powders, non-injectable gels, pastes, and ointments. This is important in the treatment of wounds with irregular shapes and depth. This study identified an injectable hydrogel formulation of porcine cholecyst extracellular matrix (60%) in medical-grade carboxymethyl cellulose (40%) as vehicle and evaluated its biomaterial properties. Further, an in-depth evaluation of in vivo wound healing efficacy was conducted in a rat full-thickness skin excision wound healing model, which revealed that the hydrogel formulation accelerated wound healing process compared to wounds treated with a commercial formulation and untreated wounds. The hydrogel appeared to have promoted a desirable pro-regenerative tissue reaction predominated by Th2 helper lymphocytes and M2 macrophages as well as an effective collagen remodeling indicative of diminished scarring. In conclusion, the porcine cholecyst extracellular matrix injectable hydrogel formulation appeared to be a promising candidate formulation as an advanced wound care biomaterial for faster healing of skin wounds with minimal scarring.

Double-alternating injectable multifunctional hydrogel based on chitosan for skin wound repair

Injectable hydrogels can be suitable for any irregular wounds to play an important role in wound healing, which have attracted much attention from researchers. Here, a chitosan-based double alternating injectable hydrogel had been proposed, which aligned with characteristics of wound healing. First of all, carboxymethyl chitosan (CMCS) and oxidized gellant (OGG) were used to fabricate above double-alternating injectable hydrogel skeleton (COG) through Schiff base bond. Then, dipotassium glycyrrhizinate (DPG) and bioactive glass (BG) were loaded respectively into COG, forming COG2-D10 and COG2-B0.5 hydrogel. Various properties of above hydrogels such as rheological behaviors, injectable capability, cytocompatibility, antibacterial and anti-inflammatory activity were systematically investigated. The results indicated that above hydrogel not only had a stable network structure, good toughness, injectability, and excellent adhesive properties, but also exhibited efficient antibacterial, anti-inflammatory, hemostatic, and biocompatible properties. The investigation of in vivo full-thickness skin wound healing showed that compared with COG2-D10 or COG2-B0.5 hydrogel alone, the double-alternating COG2-D10/COG2-B0.5 hydrogel could better enhance the efficacy of drugs, promote cell migration and proliferation, accelerate collagen fiber deposition and neovascularization, and significantly improve wound healing (p < 0.01). Therefore, the double-alternating therapy strategy of hydrogel will provide a new approach for the clinical treatment of skin wound healing.

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.

Involvement of macromolecules in 3D printing for wound healing management: A narrative review

Wound healing comprises four overlapping stages involving complex biochemical and cellular processes. Any lapse in this procedure causes irregular healing, which generates clinical and financial burdens for the health system. Personalized treatment is preferred to overcome the limitations of classical as well as modern methods of wound healing. This review discusses recently developed 3D printing models for personalized treatment with varying degrees of success. It is an effective approach for treating wounds by developing custom dressings tailored to the patient's needs and reducing incidents of infections. Additionally, incorporating natural or synthetic polymers can further enhance their effectiveness. Macromolecular polymers, laminin, cellulose, collagen, gelatin, etc. that make up the bulk of 3D printable bio-inks, have been essential in diverse 3D bioprinting technologies throughout the layered 3D manufacturing processes. The polymers need to be tailored for the specific requirements of printing and effector functions in cancer treatment, dental & oral care, biosensors, and muscle repair. We have explored how 3D printing can be utilized to fasten the process of wound healing at each of the four stages. The benefits as well as the future prospects are also discussed in this article.

Doxycycline-loaded carboxymethyl cellulose/sodium alginate/gelatin hydrogel: An approach for enhancing pressure ulcer healing in a rat model

Pressure ulcers, or bedsores, are created by areas of the skin under prolonged pressure and can lead to skin and underlying tissue damage. The present study evaluated the effects of carboxymethyl cellulose/sodium alginate/gelatin (CMC/Alg/Gel) hydrogel containing doxycycline (DOX) on improving the healing process of pressure ulcers. The magnet was used to apply pressure on the dorsum skin rat to induce a pressure ulcer model. Then sterile gauze, CMC/Alg/Gel, and CMC/Alg/Gel/1% w/v DOX hydrogels were used to cover the wounds. Blood compatibility, weight loss, cytocompatibility, drug release rate, cell viability, wound closure, and re-epithelialization were evaluated in all animals on the 14th day after treatment. In vivo results and histopathological evaluation showed 56.66% wound closure and the highest re-epithelialization in the CMC/Alg/Gel/1% w/v DOX hydrogel group (14 days after treatment). Furthermore, real-time PCR results indicated that the hydrogel containing DOX significantly decreased the expression of the MMP family consisting of MMP2 and MMP9 mRNA and also increased the expression of vascular endothelial growth factor VEGF mRNA. This study suggested that the addition of DOX, an antibiotic and MMP inhibitor, to hydrogels may be effective in the healing process of pressure ulcers.

Advancing burn wound treatment: exploring hydrogel as a transdermal drug delivery system

Burn injuries are prevalent and life-threatening forms that contribute significantly to mortality rates due to associated wound infections. The management of burn wounds presents substantial challenges. Hydrogel exhibits tremendous potential as an ideal alternative to traditional wound dressings such as gauze. This is primarily attributed to its three-dimensional (3D) crosslinked polymer network, which possesses a high water content, fostering a moist environment that supports effective burn wound healing. Additionally, hydrogel facilitates the penetration of loaded therapeutic agents throughout the wound surface, combating burn wound pathogens through the hydration effect and thereby enhancing the healing process. However, the presence of eschar formation on burn wounds obstructs the passive diffusion of therapeutics, impairing the efficacy of hydrogel as a wound dressing, particularly in cases of severe burns involving deeper tissue damage. This review focuses on exploring the potential of hydrogel as a carrier for transdermal drug delivery in burn wound treatment. Furthermore, strategies aimed at enhancing the transdermal delivery of therapeutic agents from hydrogel to optimize burn wound healing are also discussed.

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.

Cord Blood Platelet Lysate-Loaded Thermo-Sensitive Hydrogels for Potential Treatment of Chronic Skin Wounds

BACKGROUND/OBJECTIVES

Chronic skin wounds (CSWs) are a worldwide healthcare problem with relevant impacts on both patients and healthcare systems. In this context, innovative treatments are needed to improve tissue repair and patient recovery and quality of life. Cord blood platelet lysate (CB-PL) holds great promise in CSW treatment thanks to its high growth factors and signal molecule content. In this work, thermo-sensitive hydrogels based on an amphiphilic poly(ether urethane) (PEU) were developed as CB-PL carriers for CSW treatment.

METHODS

A Poloxamer 407®-based PEU was solubilized in aqueous medium (10 and 15% w/v) and added with CB-PL at a final concentration of 20% v/v. Hydrogels were characterized for their gelation potential, rheological properties, and swelling/dissolution behavior in a watery environment. CB-PL release was also tested, and the bioactivity of released CB-PL was evaluated through cell viability, proliferation, and migration assays.

RESULTS

PEU aqueous solutions with concentrations in the range 10-15% w/v exhibited quick (within a few minutes) sol-to-gel transition at around 30-37 °C and rheological properties modulated by the PEU concentration. Moreover, CB-PL loading within the gels did not affect the overall gel properties. Stability in aqueous media was dependent on the PEU concentration, and payload release was completed between 7 and 14 days depending on the polymer content. The CB-PL-loaded hydrogels also showed biocompatibility and released CB-PL induced keratinocyte migration and proliferation, with scratch wound recovery similar to the positive control (i.e., CB-PL alone).

CONCLUSIONS

The developed hydrogels represent promising tools for CSW treatment, with tunable gelation properties and residence time and the ability to encapsulate and deliver active biomolecules with sustained and controlled kinetics.

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.

Skin metabolism in obesity: A narrative review

Obesity is a complex multifactorial disease in which excess body fat triggers negative health effects. Systemically, obesity causes several changes, such as inflammation, oxidative stress, mitochondrial dysfunction and apoptosis; factors linked to the slow and incomplete epithelial regenerative process. Specifically, in the integumentary system, obesity causes an expansion of the skin's surface area and changes in collagen deposition. Molecular underpinnings of why obesity delays wound healing are still poorly understood. In addition to the primary role of dermal adipocytes in lipid storage and heat insulation, they also promote skin immunity, wound healing and hair follicle cycling. As a consequence of the cellular and dysfunctional adaptations of adipocytes, inflammatory immune alterations, alteration in the expression of proteins genes associated with the blood supply, altered collagen formation through fibroblast senescence and excessive degradation of extracellular matrix proteins are metabolic characteristics of the system in obesity that contribute to sustained inflammation and decreased mechanical resistance of the skin.

Double Enzyme Active Hydrogel Program Regulates the Microenvironment of Staphylococcus aureus-Infected Pressure Ulcers

The treatment of infected pressure ulcers (IUPs) requires addressing diverse microenvironments. A pressing challenge is to effectively enhance the regenerative microenvironment at different stages of the healing process, tailoring interventions as needed. Here, a dual enzyme mimetic and bacterial responsive self-activating antimicrobial hydrogel designed to enhance IPUs healing is introduced. This hydrogel incorporates pH-responsive dual enzyme-active nanoplatforms (HNTs-Fe-Ag) encapsulated within a methacrylate-modified silk fibroin (SFMA) and dopamine methacrylamide (DMA) matrix. This composite hydrogel exhibits adaptive microenvironment regulation capabilities. Under the low pH microenvironment of bacterial infection, it has excellent antimicrobial activity by self-activating the •OH generation in conjunction with photothermal effects. Under the neutral and alkaline microenvironment of chronic inflammation, it catalyzes the decomposition of hydrogen peroxide (H2O2) to produce oxygen (O2), thereby alleviating hypoxia and scavenging reactive oxygen species (ROS), which in turn remodulates the phenotype of macrophages. The composite hydrogel demonstrates on-demand therapeutic effects in the microenvironment of infected wounds, significantly enhancing the regenerative microenvironment of IUPs by promoting wound closure, inflammation regulation, and collagen deposition through self-activated antimicrobial action during infection and adaptive hypoxia relief during recovery. This approach offers a novel strategy for developing smart wound dressings.

The Potential of Human Wharton's Jelly Mesenchymal Stem Cells Secretome Based Topical Gel for Therapeutic Application

Background

Diabetic Foot Ulcer (DFU) might be worsened by neuropathy and vascular issues. This condition can cause 14.3% fatality, stressing the need for effective wound healing therapy. Wound healing is a complex biological process, and human Wharton's Jelly Mesenchymal Stem Cells (hWJMSCs) may help manage DFU treatment issues. This research focuses on utilizing a gel carrier to deliver bioactive substances from Wharton's Jelly Mesenchymal Stem Cells secretome (hWJ-MSCs-Sec) as a possible treatment for DFU.

Methods

To maintain quality, hWJMSCs-Sec is thoroughly mixed with carbomer gel and freeze-dried. ELISA test is performed to determine the characterization of the gel of hWJMSCs-Sec such as Keratinocyte Growth Factor (KGF), Platelet-Derived Growth Factor (PDGF), Hepatocyte Growth Factor (HGF), Epidermal Growth Factor (EGF), and Heparin-Binding EGF-Like Growth Factor (HB-EGF). The antioxidant activity was also measured with Hydrogen peroxide (H2O2), Nitric oxide (NO), and Ferric Reducing Antioxidant Power (FRAP) assay. Proliferation assay was utilized using WST-8 and the wound healing potential was assessed via the migration cell ability of scratched-human skin fibroblast (BJ cells).

Results

The freeze-dried hWJ-MSCs-Sec showed higher levels of KGF, HGF, PDGF, EGF, HB-EGF, and the antioxidant activities compared to fresh hWJ-MSCs-Sec. Additionally, the gel of freeze-dried hWJ-MSCs-Sec exhibited higher levels compared to the gel of fresh hWJMSCs-Sec. This was evidenced by faster closure of scratched wounds on BJ cells treated with hWJMSCs-Sec and freeze-dried hWJ-MSCs-Sec gel.

Conclusion

The freeze-dried hWJ-MSCs-Sec gel exhibits superior quality compared to the non-freeze-dried hWJ-MSCs-Sec gel. This demonstrates that the freeze-drying procedure can maintain the bioactive chemicals found in hWJMSCs-Sec, potentially enhancing the efficacy of this gel in promoting cell regeneration for wound healing.

Stimuli-responsive drug delivery systems for inflammatory skin conditions

Inflammatory skin conditions highly influence the quality of life of the patients suffering from these disorders. Symptoms include red, itchy and painful skin lesions, which are visible to the rest of the world, causing stigmatization and a significantly lower mental health of the patients. Treatment options are often unsatisfactory, as they suffer from either low patient adherence or the risk of severe side effects. Considering this, there is a need for new treatments, and notably of new ways of delivering the drugs. Stimuli-responsive drug delivery systems are able to deliver their drug cargo in response to a given stimulus and are, thus, promising for the treatment of inflammatory skin conditions. For example, the use of external stimuli such as ultraviolet light, near infrared radiation, or alteration of magnetic field enables drug release to be precisely controlled in space and time. On the other hand, internal stimuli induced by the pathological condition, including pH alteration in the skin or upregulation of reactive oxygen species or enzymes, can be utilized to create drug delivery systems that specifically target the diseased skin to achieve a better efficacy and safety. In the latter context, however, it is of key importance to match the trigger mechanism of the drug delivery system to the actual pathological features of the specific skin condition. Hence, the focus of this article is placed not only on reviewing stimuli-responsive drug delivery systems developed to treat specific inflammatory skin conditions, but also on critically evaluating their efficacy in the context of specific skin diseases. STATEMENT OF SIGNIFICANCE: Skin diseases affect one-third of the world's population, significantly lowering the quality of life of the patients, who deal with symptoms such as painful and itchy skin lesions, as well as stigmatization due to the visibility of their symptoms. Current treatments for inflammatory skin conditions are often hampered by low patient adherence or serious drug side effects. Therefore, more emphasis should be placed on developing innovative formulations that provide better efficacy and safety for patients. Stimuli-responsive drug delivery systems hold considerable promise in this regard, as they can deliver their cargo precisely where and when it is needed, reducing adverse effects and potentially offering better treatment outcomes.

From lab to wearables: Innovations in multifunctional hydrogel chemistry for next-generation bioelectronic devices

Functional hydrogels have emerged as foundational materials in diagnostics, therapy, and wearable devices, owing to their high stretchability, flexibility, sensing, and outstanding biocompatibility. Their significance stems from their resemblance to biological tissue and their exceptional versatility in electrical, mechanical, and biofunctional engineering, positioning themselves as a bridge between living organisms and electronic systems, paving the way for the development of highly compatible, efficient, and stable interfaces. These multifaceted capability revolutionizes the essence of hydrogel-based wearable devices, distinguishing them from conventional biomedical devices in real-world practical applications. In this comprehensive review, we first discuss the fundamental chemistry of hydrogels, elucidating their distinct properties and functionalities. Subsequently, we examine the applications of these bioelectronics within the human body, unveiling their transformative potential in diagnostics, therapy, and human-machine interfaces (HMI) in real wearable bioelectronics. This exploration serves as a scientific compass for researchers navigating the interdisciplinary landscape of chemistry, materials science, and bioelectronics.

Stem Cells in Bone Tissue Engineering: Progress, Promises and Challenges

Bone defects from accidents, congenital conditions, and age-related diseases significantly impact quality of life. Recent advancements in bone tissue engineering (TE) involve biomaterial scaffolds, patient-derived cells, and bioactive agents, enabling functional bone regeneration. Stem cells, obtained from numerous sources including umbilical cord blood, adipose tissue, bone marrow, and dental pulp, hold immense potential in bone TE. Induced pluripotent stem cells and genetically modified stem cells can also be used. Proper manipulation of physical, chemical, and biological stimulation is crucial for their proliferation, maintenance, and differentiation. Stem cells contribute to osteogenesis, osteoinduction, angiogenesis, and mineralization, essential for bone regeneration. This review provides an overview of the latest developments in stem cell-based TE for repairing and regenerating defective bones.

Exosome Loaded Protein Hydrogel for Enhanced Gelation Kinetics and Wound Healing

Exosomes are being increasingly explored in biomedical research for wound healing applications. Exosomes can improve blood circulation and endocrine signaling, resulting in enhanced cell regeneration. However, exosome treatments suffer from low retention and bioavailability of exosomes at the wound site. Hydrogels are a popular tool for drug delivery due to their ability to encapsulate drugs in their network and allow for targeted release. Recently, hydrogels have proven to be an effective method to provide increased rates of wound healing when combined with exosomes that can be applied noninvasively. We have designed a series of single-domain protein-based hydrogels capable of physical cross-linking and upper critical solution temperature (UCST) behavior. Hydrogel variant Q5, previously designed with improved UCST behavior and a significantly enhanced gelation rate, is selected as a candidate for encapsulation release of exosomes dubbed Q5Exo. Q5Exo exhibits low critical gelation times and significant decreases in wound healing times in a diabetic mouse wound model showing promise as an exosome-based drug delivery tool and for future hybrid, noninvasive protein-exosome design.

Sodium alginate-based multifunctional sandwich-like system for treating wound infections

Microbial colonization and development of infections in wounds is a sign of chronicity. The prevailing approach to manage and treat these wounds involves dressings. However, these often fail in effectively addressing infections, as they struggle to both absorb exudates and maintain optimal local moisture. The system here presented was conceptualized with a three-layer design: the outer layer made of a fibrous polycaprolactone (PCL) film, to act as a barrier for preventing microorganisms and impurities from reaching the wound; the intermediate layer formed of a sodium alginate (SA) hydrogel loaded with ampicillin (Amp) for fighting infections; and the inner layer comprised of a fibrous film of PCL and polyethylene glycol (PEG) for facilitating cell recognition and preventing wound adhesion. Thermal evaluations, degradation, wettability and release behavior testing confirmed the system resistance overtime. The sandwich demonstrated the capability for absorbing exudates (≈70 %) and exhibited a controlled release of Amp for up to 24 h. Antimicrobial testing was performed against Staphylococcus aureus and Escherichia coli, as representatives of Gram-positive and Gram-negative bacteria: >99 % elimination of bacteria. Cell cytotoxicity assessments showed high cytocompatibility levels, confirming the safety of the proposed sandwich system. Adhesion assays confirmed the system ease of detaching without mechanical effort (0.37 N). Data established the efficiency of the sandwich-like system, suggesting promising applications in infected wound care.

α-Terpineol loaded, electron beam crosslinked polyvinyl alcohol/tapioca starch hydrogel sheets; fabrication, characterization and evaluation of wound healing potential on a full thickness acid burn wound

The multifaceted challenges in treating full-thickness acid burn wounds including impaired tissue regeneration, increased risk of infection, and the pursuit of functional and aesthetically pleasing outcomes, highlights the need for innovative therapeutic approaches for their treatment. The exceptional biochemical and mechanical properties of hydrogels, particularly their extracellular matrix-like nature and their potential to incorporate functional ingredients positions them as promising materials for wound dressings, offering a potential solution to the complexities of full-thickness burn wound management. The current study has integrated functional ingredients (starch and α-terpineol), known for their angiogenic, fibroblast-adhesive, and anti-inflammatory properties into an α-terpineol loaded, electron beam crosslinked polyvinyl alcohol/tapioca pearl starch hydrogel. The hydrogel was then explored for its efficacy in treating full-thickness acid burns. The hydrogel sheets, fabricated using a 25 kGy electron beam, were characterized for structural and functional properties. Surface morphology, gel fraction, swelling ratio, moisture retention capacity and thermal stability were also evaluated. PVA/tapioca starch hydrogel demonstrated optimal macroporosity, mechanical strength, thermal stability, water retention, and moisturizing ability, making it ideal for the intended application. In vitro skin compatibility analysis of α-terpineol-loaded hydrogel confirmed its biocompatibility, demonstrating 90% fibroblast viability. In vivo sensitivity testing on normal rat skin showed no inflammatory response. Analysis of the full-thickness rat chemical burn wounds treated with the hydrogels demonstrated that α-terpineol (AT) loaded e-beam crosslinked PVA/tapioca starch hydrogels increased the rate of wound closure, promoted re-epithelialization, facilitated collagen deposition, stimulated angiogenesis, and promoted keratin deposition, ultimately leading to healing of both thick dermal and epidermal tissues, as well as partial restoration of skin appendages over a duration of 30 days as confirmed by the histological and immunohistochemistry staining. Collectively, this study indicates that α-terpineol (AT) loaded e-beam crosslinked PVA/tapioca starch hydrogel holds promise as a cost-effective and efficient wound dressing for expediting full thickness acid burn wound healing, thus expanding the practical applications of the natural polymer based sheet hydrogel dressings.

An Overview of Wound Dressing Materials

Wounds are an increasing global concern, mainly due to a sedentary lifestyle, frequently associated with the occidental way of life. The current prevalence of obesity in Western societies, leading to an increase in type II diabetes, and an elderly population, is also a key factor associated with the problem of wound healing. Therefore, it stands essential to find wound dressing systems that allow for reestablishing the skin integrity in the shortest possible time and with the lowest cost, avoiding further damage and promoting patients' well-being. Wounds can be classified into acute or chronic, depending essentially on the duration of the healing process, which is associated withextent and depth of the wound, localization, the level of infection, and the patient's health status. For each kind of wound and respective healing stage, there is a more suitable dressing. The aim of this review was to focus on the possible wound dressing management, aiming for a more adequate healing approach for each kind of wound.

Fabrication and Evaluation of a Soy Protein Isolate/Collagen/Sodium Alginate Multifunctional Bilayered Wound Dressing: Release of Cinnamaldehyde, Artemisia absinthium, and Oxygen

Chronic wounds, such as diabetic ulcers and pressure sores, pose significant challenges in modern healthcare due to their prolonged healing times and susceptibility to infections. This study aims to engineer a bilayered wound dressing (BLWD) composed of soy protein isolate/collagen with the ability to release Cinnamaldehyde, Artemisia absinthium (AA), and oxygen. Cinnamaldehyde, magnesium peroxide (MgO2), and AA extract were encapsulated. Nanoparticles were evaluated using scanning electron microscopy (SEM), dynamic light scattering, and ZETA potential tests. Swelling, degradation, water vapor penetration, tensile, MTT, SEM, oxygen release, AA extract release, and antibacterial properties were performed. An in vivo study was carried out to assess the final wound dressing under Hematoxiline&Eosin and Masson trichrome staining analysis and compared to a commercial product. According to the results, the synthesized nanoparticles had an average diameter of about 20 nm with a zeta potential in the range of -20 to -30 mV. The layers had uniform and dense surfaces. The maximum swelling and degradation of the dressing was about 130 and 13% respectively. Generally, better mechanical properties were observed in BLWD than in the single-layer case. More than 90% biocompatibility for the wound dressing was reported. The BLWD could inhibit the growth of Gram-positive and Gram-negative microorganisms. Histopathological analysis showed an acceptable wound-healing property. To sum up, the engineered wound dressing can be a good candidate for more clinical trials.

Release of natural extracts from PVA and PVA-CMC hydrogel wound dressings: a power law swelling/delivery

Introduction

PVA hydrogels present many characteristics of the ideal dressing, although without antimicrobial properties. The present work aims to study the physical, mechanical and release characteristics of hydrogel wound dressings loaded with either of two natural herbal products, sage extract and dragon's blood.

Methods

Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and tensile mechanical testing were used to investigate the structure and properties of the gels. Swelling and degradation tests were conducted according to ISO 10993-9. Release characteristics were studied using UV Spectrophotometry.

Results

PVA matrices incorporating sage extract or dragon's blood (DB) present hydrogen bonding between these components. PVA-CMC hydrogels containing sage present similar spectra to PVA-CMC alone, probably indicating low miscibility or interaction between the matrix and sage. The opposite is found for DB, which exhibits more pronounced interference with crystallinity than sage. DB and NaCMC negatively affect Young's modulus and failure strength. All samples appear to reach equilibrium swelling degree (ESD) in 24 h. The addition of DB and sage to PVA increases the gels' swelling capacity, indicating that the substances likely separate PVA chains. The inclusion of CMC contributes to high media uptake. The kinetics profile of media uptake for 4 days is described by a power-law model, which is correlated to the drug delivery mechanism.

Discussion

A PVA-CMC gel incorporating 15% DB, the highest amount tested, shows the most favorable characteristics for flavonoid delivery, as well as flexibility and swelling capacity.

Disodium Cromoglycate Templates Anisotropic Short-Chain PEG Hydrogels

Anisotropic hydrogels have found widespread applications in biomedical engineering, particularly as scaffolds for tissue engineering. However, it remains a challenge to produce them using conventional fabrication methods, without specialized synthesis or equipment, such as 3D printing and unidirectional stretching. In this study, we explore the self-assembly behaviors of polyethylene glycol diacrylate (PEGDA), using disodium cromoglycate (DSCG), a lyotropic chromonic liquid crystal, as a removable template. The affinity between short-chain PEGDA (Mn = 250) and DSCG allows polymerization to take place at the DSCG surface, thereby forming anisotropic hydrogel networks with fibrin-like morphologies. This process requires considerable finesse as the phase behaviors of DSCG depend on a multitude of factors, including the weight percentage of PEGDA and DSCG, the chain length of PEGDA, and the concentration of ionic species. The key to modulating the microstructures of the all-PEG hydrogel networks is through precise control of the DSCG concentration, resulting in anisotropic mechanical properties. Using these anisotropic hydrogel networks, we demonstrate that human dermal fibroblasts are particularly sensitive to the alignment order. We find that cells exhibit a density-dependent activation pattern of a Yes-associated protein, a mechanotransducer, corroborating its role in enabling cells to translate external mechanical and morphological patterns to specific behaviors. The flexibility of modulating microstructure, along with PEG hydrogels' biocompatibility and biodegradability, underscores their potential use for tissue engineering to create functional structures with physiological morphologies.

Controlled release of vancomycin from PEGylated fibrinogen polyethylene glycol diacrylate hydrogel

Surgical site infection (SSI) is a common issue post-surgery which often prolongs hospitalization and can lead to serious complications such as sternal wound infection following cardiac surgery via median sternotomy. Controlled release of suitable antibiotics could allow maximizing drug efficacy and safety, and therefore achieving a desired therapeutic response. In this study, we have developed a vancomycin laden PEGylated fibrinogen-polyethylene glycol diacrylate (PF-PEGDA) hydrogel system that can release vancomycin at a controlled and predictable rate to be applied in SSI prevention. Two configurations were developed to study effect of the hydrogel on drug release, namely, vancomycin laden hydrogel and vancomycin solution on top of blank hydrogel. The relationship between the rigidity of the hydrogel and drug diffusion was found to comply with a universal power law, i.e., softer hydrogels result in a greater diffusion coefficient hence faster release rate. Besides, vancomycin laden hydrogels exhibited burst release, whereas the vancomycin solution on top of blank hydrogels exhibited lag release. A mathematical model was developed to simulate vancomycin permeation through the hydrogels. The permeation of vancomycin can be predicted accurately by using the mathematical model, which provided a useful tool to customize drug loading, hydrogel thickness and stiffness for personalized medication to manage SSI. To evaluate the potential of hydrogels for bone healing applications in cardiovascular medicine, we performed a proof-of-concept median sternotomy in rabbits and applied the hydrogels. The hydrogel formulations accelerated the onset of osteo-genetic processes in rabbits, demonstrating its potential to be used in human.

Development and characterization of polyethylene oxide and guar gum-based hydrogel; a detailed in-vitro analysis of degradation and drug release kinetics

Herein, we synthesized hydrogel films from crosslinked polyethylene oxide (PEO) and guar gum (GG) which can offer hydrophilicity, antibacterial efficacy, and neovascularization. This study focuses on synthesis and material/biological characterization of rosemary (RM) and citric acid (CA) loaded PEO/GG hydrogel films. Scanning Electron Microscopy images confirmed the porous structure of the developed hydrogel film matrix (PEO/GG) and the dispersion of RM and CA within it. This porous structure promotes moisture adsorption, cell attachment, proliferation, and tissue layer formation. Fourier Transform Infrared Spectroscopy (FTIR) further validated the crosslinking of the PEO/GG matrix, as confirmed by the appearance of C-O-C linkage in the FTIR spectrum. PEO/GG and PEO/GG/RM/CA revealed similar degradation and release kinetics in Dulbecco's Modified Eagle Medium, Simulated Body Fluid, and Phosphate Buffer Saline (degradation of ∼55 % and release of ∼60 % RM in 168 h.). The developed hydrogel film exhibited a zone of inhibition against Escherichia. coli (2 mm) and Staphylococcus. aureus (9 mm), which can be attributed to the presence of RM in the hydrogel film. Furthermore, incorporating CA in the hydrogel film promoted neovascularization, as confirmed by the Chorioallantoic Membrane Assay. The developed RM and CA-loaded PEO/GG-based hydrogel films offered suitable in-vitro properties that may aid in potential wound healing applications.

Enhancing pressure ulcer healing and tissue regeneration by using N-acetyl-cysteine loaded carboxymethyl cellulose/gelatin/sodium alginate hydrogel

Prolonged pressure on the skin can result in pressure ulcers, which may lead to serious complications, such as infection and tissue damage. In this study, we evaluated the effect of a carboxymethyl cellulose/gelatin/sodium alginate (CMC/Gel/Alg) hydrogel containing N-acetyl-cysteine (NAC) on the healing of pressure ulcers. Pressure ulcers were induced by applying a magnet to the dorsum of rat skin. The wounds were then treated with sterile gauze, ChitoHeal Gel®, and CMC/Gel/Alg hydrogel dressings with or without NAC for the other groups. We evaluated the morphology, weight loss, swelling, rheology, blood compatibility, cytocompatibility, antioxidant capacity, and wound scratch of the prepared hydrogel. MTT assay revealed that the optimum concentration of NAC was 5 mg/ml, which induced higher cell proliferation and viability. Results of the histopathological evaluation showed increased wound closure, and complete re-epithelialization in the hydrogel-containing NAC group compared to the other groups. The CMC/Gel/Alg/5 mg/ml NAC hydrogel dressing showed 84% wound closure at 14 days after treatment. Immunohistochemical results showed a decrease in the level of TNF-α on day 14 compared day 7. Results of the qPCR assay revealed that NAC hydrogel increased the expression of Collagen type I and TGF-β1 and decreased MMP2 and MMP9 mRNA on the 14th day. The results suggest that the CMC/Gel/Alg/5 mg/ml NAC hydrogel with antioxidant properties is an appropriate dressing for wound healing.

Hyaluronic Acid/Chondroitin Sulfate-Based Dynamic Thiol-Aldehyde Addition Hydrogel: An Injectable, Self-Healing, On-Demand Dissolution Wound Dressing

Frequent removal and reapplication of wound dressings can cause mechanical disruption to the healing process and significant physical discomfort for patients. In response to this challenge, a dynamic covalent hydrogel has been developed to advance wound care strategies. This system comprises aldehyde functionalized chondroitin sulfate (CS-CHO) and thiolated hyaluronic acid (HA-SH), with the distinct ability to form in situ via thiol-aldehyde addition and dissolve on-demand via the thiol-hemithioacetal exchange reaction. Although rarely reported, the dynamic covalent reaction of thiol-aldehyde addition holds great promise for the preparation of dynamic hydrogels due to its rapid reaction kinetics and easy reversible dissociation. The thiol-aldehyde addition chemistry provides the hydrogel system with highly desirable characteristics of rapid gelation (within seconds), self-healing, and on-demand dissolution (within 30 min). The mechanical and dissolution properties of the hydrogel can be easily tuned by utilizing CS-CHO materials of different aldehyde functional group contents. The chemical structure, rheology, self-healing, swelling profile, degradation rate, and cell biocompatibility of the hydrogels are characterized. The hydrogel possesses excellent biocompatibility and proves to be significant in promoting cell proliferation in vitro when compared to a commercial hydrogel (HyStem® Cell Culture Scaffold Kit). This study introduces the simple fabrication of a new dynamic hydrogel system that can serve as an ideal platform for biomedical applications, particularly in wound care treatments as an on-demand dissolvable wound dressing.

The Diels-Alder Cross-Linked Gelatin/Dextran Nanocomposite Hydrogels with Silver Nanoparticles for Wound Healing Applications: Synthesis, Characterization, and In Vitro Evaluation

Wound healing involves a sophisticated biological process that relies on ideal conditions to advance through various stages of repair. Modern wound dressings are designed to imitate the natural surroundings around cells and offer properties such as moisture regulation, strength, and antimicrobial defense to boost healing. A recent research project unveiled a new type of gelatin (Gel)/dextran (Dex) hydrogels, linked through Diels-Alder (D-A) reactions, loaded with silver nanoparticles (Ag-NPs) for cutting-edge wound treatment. Gel and Dex were chemically modified to form the hydrogels via the D-A reaction. The hydrogels were enriched with Ag-NPs at varying levels. Thorough analyses of the hydrogels using methods like NMR, FT-IR, and SEM were carried out to assess their structure and nanoparticle integration. Rheological tests displayed that the hydrogels had favorable mechanical attributes, particularly when Ag-NPs were included. The hydrogels demonstrated controlled swelling, responsiveness to pH changes, and were non-toxic. Testing against E. coli showcased the strong antibacterial activity of the nanocomposite hydrogels in a concentration-dependent manner. This investigation showcased the promise of these bioactive nanocomposite hydrogels in promoting speedy wound healing by maintaining a moist environment, offering an antimicrobial shield, and ensuring mechanical support at the wound site.

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

Current trend on preparation, characterization and biomedical applications of natural polysaccharide-based nanomaterial reinforcement hydrogels: A review

The tunable properties of hydrogels have led to their widespread use in various biomedical applications such as wound treatment, drug delivery, contact lenses, tissue engineering and 3D bioprinting. Among these applications, natural polysaccharide-based hydrogels, which are fabricated from materials like agarose, alginate, chitosan, hyaluronic acid, cellulose, pectin and chondroitin sulfate, stand out as preferred choices due to their biocompatibility and advantageous fabrication characteristics. Despite the inherent biocompatibility, polysaccharide-based hydrogels on their own tend to be weak in physiochemical and mechanical properties. Therefore, further reinforcement in the hydrogel is necessary to enhance its suitability for specific applications, ensuring optimal performance in diverse settings. Integrating nanomaterials into hydrogels has proven effective in improving the overall network and performance of the hydrogel. This approach also addresses the limitations associated with pure hydrogels. Next, an overview of recent trends in the fabrication and applications of hydrogels was presented. The characterization of hydrogels was further discussed, focusing specifically on the reinforcement achieved with various hydrogel materials used so far. Finally, a few challenges associated with hydrogels by using polysaccharide-based nanomaterial were also presented.

Antibacterial adhesive based on oxidized tannic acid-chitosan for rapid hemostasis

Currently, bacterial infections and bleeding interfere with wound healing, and multifunctional hydrogels with appropriate blood homeostasis, skin adhesion, and antibacterial activity are desirable. In this study, chitosan-based hydrogels were synthesized using oxidized tannic acid (OTA) and Fe3+ as cross-linkers (CS-OTA-Fe) by forming covalent, non-covalent, and metal coordination bonds between Fe3+ and OTA. Our results demonstrated that CS-OTA-Fe hydrogels showed antibacterial properties against Gram-positive bacteria (Staphylococcus aureus)and Gram-negative bacteria (Escherichia coli), low hemolysis rate (< 2 %), rapid blood clotting ability, in vitro (< 2 min), and in vivo (90 s) in mouse liver bleeding. Additionally, increasing the chitosan concentration from 3 wt% to 4.5 wt% enhanced cross-linking in the network, leading to a significant improvement in the strength (from 106 ± 8 kPa to 168 ± 12 kPa) and compressive modulus (from 50 ± 9 kPa to 102 ± 14 kPa) of hydrogels. Moreover, CS-OTA-Fe hydrogels revealed significant adhesive strength (87 ± 8 kPa) to the cow's skin tissue and cytocompatibility against L929 fibroblasts. Overall, multifunctional CS-OTA-Fe hydrogels with tunable mechanical properties, excellent tissue adhesive, self-healing ability, good cytocompatibility, and fast hemostasis and antibacterial properties could be promising candidates for biomedical applications.

Advanced Dressings for Chronic Wound Management

Wound healing, particularly for chronic wounds, presents a considerable difficulty due to differences in biochemical and cellular processes that occur in different types of wounds. Recent technological breakthroughs have notably advanced the understanding of diagnostic and therapeutic approaches to wound healing. The evolution in wound care has seen a transition from traditional textile dressings to a variety of advanced alternatives, including self-healing hydrogels, hydrofibers, foams, hydrocolloids, environment responsive dressings, growth factor-based therapy, bioengineered skin substitutes, and stem cell and gene therapy. Technological advancements, such as 3D printing and electronic skin (e-skin) therapy, contribute to the customization of wound healing. Despite these advancements, effectively managing chronic wounds remains challenging. This necessitates the development of treatments that consider performance, risk-benefit balance, and cost-effectiveness. This review discusses innovative strategies for the healing of chronic wounds. Incorporating biomarkers into advanced dressings, coupled with corresponding biosensors and drug delivery formulations, enables the theranostic approach to the treatment of chronic wounds. Furthermore, integrating advanced dressings with power sources and user interfaces like near-field communication, radio frequency identification, and Bluetooth enhances real-time monitoring and on-demand drug delivery. It also provides a thorough evaluation of the advantages, patient compliance, costs, and durability of advanced dressings, emphasizing smart formulations and their preparation methods.

Multifunctional antibacterial hydrogels for chronic wound management

Chronic wounds have gradually evolved into a global health challenge, comprising long-term non-healing wounds, local tissue necrosis, and even amputation in severe cases. Accordingly, chronic wounds place a considerable psychological and economic burden on patients and society. Chronic wounds have multifaceted pathogenesis involving excessive inflammation, insufficient angiogenesis, and elevated reactive oxygen species levels, with bacterial infection playing a crucial role. Hydrogels, renowned for their excellent biocompatibility, moisture retention, swelling properties, and oxygen permeability, have emerged as promising wound repair dressings. However, hydrogels with singular functions fall short of addressing the complex requirements associated with chronic wound healing. Hence, current research emphasises the development of multifunctional antibacterial hydrogels. This article reviews chronic wound characteristics and the properties and classification of antibacterial hydrogels, as well as their potential application in chronic wound management.

Advancements in Hybrid Cellulose-Based Films: Innovations and Applications in 2D Nano-Delivery Systems

This review paper delves into the realm of hybrid cellulose-based materials and their applications in 2D nano-delivery systems. Cellulose, recognized for its biocompatibility, versatility, and renewability, serves as the core matrix for these nanomaterials. The paper offers a comprehensive overview of the latest advancements in the creation, analysis, and application of these materials, emphasizing their significance in nanotechnology and biomedical domains. It further illuminates the integration of nanomaterials and advanced synthesis techniques that have significantly improved the mechanical, chemical, and biological properties of hybrid cellulose-based materials.

Recent trends in targeted delivery of smart nanocarrier-based microbial enzymes for therapeutic applications

Smart carrier-based immobilization has widened the use of enzymes for the treatment of several disorders. Large surface areas, tunable morphology, and surface modification ability aid the targeted and controlled release of therapeutic enzymes from such formulations. Smart nanocarriers, such as polymeric carriers, liposomes, and silica have also increased the stability, half-life, and permeability of these enzymes. In this review, summarize recent advances in the smart immobilization of microbial enzymes and their development as precision nanomedicine for the treatment of cancer, thrombosis, phenylketonuria (PKU), and wound healing. We also discuss the challenges and measures to be adopted for the successful clinical translation of these formulations.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

Oxidized alginate-gelatin (ADA-GEL)/silk fibroin/Cu-Ag doped mesoporous bioactive glass nanoparticle-based hydrogels for potential wound care treatments

The present work focuses on developing 5% w/v oxidized alginate (alginate di aldehyde, ADA)-7.5% w/v gelatin (GEL) hydrogels incorporating 0.25% w/v silk fibroin (SF) and loaded with 0.3% w/v Cu-Ag doped mesoporous bioactive glass nanoparticles (Cu-Ag MBGNs). The microstructural, mechanical, and biological properties of the composite hydrogels were characterized in detail. The porous microstructure of the developed ADA-GEL based hydrogels was confirmed by scanning electron microscopy, while the presence of Cu-Ag MBGNs in the synthesized hydrogels was determined using energy dispersive x-ray spectroscopy. The incorporation of 0.3% w/v Cu-Ag MBGNs reduced the mechanical properties of the synthesized hydrogels, as investigated using micro-tensile testing. The synthesized ADA-GEL loaded with 0.25% w/v SF and 0.3% w/v Cu-Ag MBGNs showed a potent antibacterial effect againstEscherichia coliandStaphylococcus aureus. Cellular studies using the NIH3T3-E1 fibroblast cell line confirmed that ADA-GEL films incorporated with 0.3% w/v Cu-Ag MBGNs exhibited promising cellular viability as compared to pure ADA-GEL (determined by WST-8 assay). The addition of SF improved the biocompatibility, degradation rate, moisturizing effects, and stretchability of the developed hydrogels, as determinedin vitro. Such multimaterial hydrogels can stimulate angiogenesis and exhibit desirable antibacterial properties. Therefore further (in vivo) tests are justified to assess the hydrogels' potential for wound dressing and skin tissue healing applications.