Hyaluronic acid-Based wound dressings: A review

Acid-responsive contractile hyaluronic acid-based hydrogel loaded with ginsenoside Rg1 for hemostasis and promotion of gastric wound healing

Due to constant stimulation by stomach acid and local bleeding, gastric tissue wounds tend to heal slowly and complications such as anastomotic leakage have a high incidence. Suturing is often used to treat gastric wounds in clinic, but it still faces risks such as bleeding, slow healing, and leakage. Recently, hydrogel have been widely used to treat various types of wounds. Although hydrogels have shown promising efficacy in wound healing, it is still a challenge in dealing with wounds in gastric tissue for the poor adaptability of traditional materials in acidic environments. Hence, a series of pH responsive and good tissue adhesive hydrogels (MA-HA/AA) based on methacryloyl hyaluronic acid (MA-HA) and acryloyl-6-aminocaproic acid (AA) via in situ photo-crosslinking were designed, and anti-inflammatory and pro-healing traditional Chinese medicines ginsenoside Rg1 was incorporated into the hydrogel to treat gastric tissue wound. These acid-responsive hydrogels could form effective acid-resistant barriers and could lead to hemostasis rapidly through its strong adhesion. Besides, the hydrogels contracted under an acidic environment, which could tighten the gastric tissue wounds and sustained release the loaded ginsenoside Rg1. In addition, the hydrogels showed excellent biocompatibility and in vivo degradability. In summary, the acid-responsive contractile hyaluronic acid hydrogel loaded with ginsenoside Rg1 had good properties for hemostasis and acid-resistance to facilitate the promotion of gastric wounds healing.

Probiotic domestication and engineering enable one-shot treatment for bladder mucosal repair

The bladder mucosa is an important blood-urine barrier in the human body, its destruction can lead to distressing cystitis. Traditional treatment approaches often require frequent catheterization and intravesical instillation of hyaluronic acid (HA), which greatly reduces patient compliance and therapeutic efficacy. Herein, we develop a probiotic-based one-shot therapy to repair bladder mucosa with improved convenience, efficacy, and biosafety. To this end, a high-biocompatible probiotic strain is engineered to secrete high-molecular-weight HA controlled by ultrasound stimulation. Meanwhile, a bacterium acclimation-inspired strategy to select bacterial cells targeting the site of bladder inflammation is also proposed. With just one-shot intravesical administration, these engineered bacteria can strongly adhere to the damaged bladder epithelium, continuously secrete HA, and stimulate the formation of protective living engineered materials on the bladder. Consequently, varying therapeutic efficacies in damaged murine model, such as reporting the site of inflammation within 28 days, accelerating mucosal repair (such as significantly increased expression of tight junction proteins occludin-1 and ZO-1), modulating innate immune reactions (such as pro-inflammatory factor levels decreased by about 50 %), and even recovering animal motion behaviors, are realized, achieving an improved therapeutic effect without detectable adverse effects.

Smart response CO hydrogel "battling" bacterial biofilms and inflammation associated with wounds

Bacterial infections accompanied by excessive inflammatory responses and bleeding can significantly impede wound healing, with biofilms further complicating treatment and reducing its effectiveness. Herein, an intelligent carbon monoxide (CO) gas-releasing and hemostatic hydrogel was developed, composed of carboxymethyl chitosan (CMCS), hyaluronic acid (HA), copper-doped mesoporous Prussian blue nanoparticles (named as Cu-HMPB NPs), luteolin, and Mn2(CO)10, through chemical and physical cross-linking. Cu-HMPB is loaded with luteolin, a natural flavonoid, and covalently bonded with the temperature-sensitive CO donor Mn2(CO)10. By utilizing cross-linking agents, CMCS and HA are physically loaded with Cu-HMPB@Lu@Mn nanoparticles (named as Cu-HLM NPs) to form the composite hydrogel (named as CuHLM/C-H). Under near-infrared (NIR) irradiation, the CuHLM/C-H hydrogel exhibited excellent photothermal capabilities and enabled on-demand CO gas release. The CO gas effectively penetrated mature biofilms and promoted their dissipation, synergizing with the photothermal effect to efficiently eradicate biofilms. The antioxidant properties of luteolin effectively prevents redox imbalance. Additionally, the CuHLM/C-H hydrogel demonstrated significant hemostatic effects in mouse liver and tail hemorrhage models. Collectively, the combination of gas therapy and photothermal therapy shows exceptional potential for addressing clinical issues caused by biofilms and associated inflammation.

Dermal fibroblast-derived extracellular matrix (ECM) synergizes with keratinocytes in promoting re-epithelization and scarless healing of skin wounds: Towards optimized skin tissue engineering

Skin serves as the first-order protective barrier against the environment and any significant disruptions in skin integrity must be promptly restored. Despite significant advances in therapeutic strategies, effective management of large chronic skin wounds remains a clinical challenge. Dermal fibroblasts are the primary cell type responsible for remodeling the extracellular matrix (ECM) in wound healing. Here, we investigated whether ECM derived from exogenous fibroblasts, in combination with keratinocytes, promoted scarless cutaneous wound healing. To overcome the limited lifespan of primary dermal fibroblasts, we established reversibly immortalized mouse dermal fibroblasts (imDFs), which were non-tumorigenic, expressed dermal fibroblast markers, and were responsive to TGF-β1 stimulation. The decellularized ECM prepared from both imDFs and primary dermal fibroblasts shared similar expression profiles of extracellular matrix proteins and promoted the proliferation of keratinocyte (iKera) cells. The imDFs-derived ECM solicited no local immune response. While the ECM and to a lesser extent imDFs enhanced skin wound healing with excessive fibrosis, a combination of imDFs-derived ECM and iKera cells effectively promoted the re-epithelization and scarless healing of full-thickness skin wounds. These findings strongly suggest that dermal fibroblast-derived ECM, not fibroblasts themselves, may synergize with keratinocytes in regulating scarless healing and re-epithelialization of skin wounds. Given its low immunogenic nature, imDFs-derived ECM should be a valuable resource of skin-specific biomaterial for wound healing and skin tissue engineering.

Encouraging collagen and epithelial layer formation via poly (lactic acid)/hyaluronic acid hybrid wound dressing containing niacinamide

This study examines the fabrication and characterization of electrospun nanofibrous mats composed of poly (lactic acid) (PLA), hybridized hyaluronic acid (HA), and niacinamide (NA) for potential applications in wound dressings. PLA and HA concentrations were changed from 4 to 12 wt% and 0.25 to 1 wt%, respectively. The morphological analysis revealed that mats with 8 wt% PLA produced smooth, bead-free fibers with an average diameter of 632 nm. Meanwhile, all concentrations of HA nanofibers had beads, except for the 1 wt%, whose average fiber diameter was 234 nm. Mechanical testing indicated that PLA-HA mats achieved a tensile strength of 4.93 MPa and elongation at a break of 88 ± 4 %. In comparison, PLA-HA-NA mats exhibited a tensile strength of 4.1 MPa but improved elongation at a break of 91 ± 4.5 %. Hydrophilicity assessments indicated that the contact angle for PLA-HA-NA was 25°, demonstrating superior fluid absorption compared to pure PLA, which had a contact angle of 109°. Drug release studies revealed that after 720 min, approximately 72.3 ± 3.6 % of NA was released from the electrospun mat, following a Korsmeyer-Peppas model with a transport exponent (n) of 0.29, indicating controlled release. In-vitro cytotoxicity tests showed cell viability rates of 94 % for PLA-HA-NA after 72 h. In-vivo studies on rats demonstrated that by day 14, wounds treated with PLA-HA-NA achieved a closure rate of 96 ± 4.6 %, compared to 93 ± 4.3 % for PLA-HA and 82 ± 3.8 % for the control group. These results highlight the potential of PLA-HA-NA nanofibers as effective wound dressings with desirable mechanical properties and biocompatibility.

Effect of cysteine transport on the molecular weight and synthesis of hyaluronic acid in Streptococcus zooepidemicus

Hyaluronic acid (HA) is a highly polymerized linear polysaccharide widely employed in cosmetics, pharmaceuticals and food. Streptococcus zooepidemicus, the primary HA industrial strain, faces high production costs and difficulties in regulating molecular weight (MW). To enhance HA yield, lactate dehydrogenase gene (ldh) was knocked out. Surprisingly, the knockout strain demonstrated a significant reduction in HA MW. To investigate the underlying mechanisms and identify novel factors affecting HA MW, transcriptome sequencing was performed on both the wild-type and knockout strain. The results revealed altered transcript levels for three presumptive cysteine transporter genes, fliY1/2/3. To assess their roles in HA synthesis, fliY1/2/3 were individually knocked out or over-expressed. It was found that overexpression of fliY1 reduced the MW further to 0.8 × 106 Da while increasing HA titer by 30 %. Additionally, the exogenous addition of cysteine was observed to lower HA MW and enhance titer. By supplementing a 3 L bioreactor with 2 g/L cysteine, the HA MW of the fliY1 overexpression strain decreased to 1.0 × 106 Da, while the titer reached 6.989 g/L. In conclusion, this study provides novel targets for genetic modification of HA-producing strains and demonstrates potential strategies for the customized production of HA with controlled MW.

Multiaction Antimicrobial, Anti-inflammatory, and Prohealing Hydrogel as a Novel Strategy for Preventing Postoperative Pancreatic Fistula

Postoperative pancreatic fistula remains a challenging complication after pancreaticoduodenectomy. Addressing this issue requires effective strategies to promote anastomotic healing. In this study, we developed a novel hydrogel designed to close pancreaticoenteric anastomosis after pancreaticoduodenectomy. The hydrogel-composed of polyvinyl alcohol, chitosan, and dopamine-modified oxidized hyaluronic acid-exhibited excellent antibacterial, anti-inflammatory, and wound healing properties. It was designed to conform well to the anastomotic site for clinical application. The hydrogel demonstrated good biocompatibility, appropriate mechanical strength, low swelling, and strong adhesive properties, meeting specific requirements for pancreaticoenteric anastomosis environments. Moreover, by activating the cell cycle, it promoted cell proliferation and migration, thereby accelerating anastomotic closure. Addition of the potent broad-spectrum antibiotic meropenem further enhanced its antibacterial efficacy, targeting common microbial species involved in delayed healing and fistula formation after pancreatic surgery. In a rat model of pancreatic fistula, the hydrogel effectively sealed the anastomosis, filled potential suture gaps, and exerted antibacterial, anti-inflammatory, and tissue regeneration-promoting effects around the anastomotic site. Therefore, this hydrogel, with its ideal degradation properties, shows promising application prospects in closing pancreaticoenteric anastomosis following pancreaticoduodenectomy, thereby offering an effective solution to reduce complications such as pancreatic fistula after pancreatic surgery.

Electrospinning a highly antibacterial polylactic acid/fibroin nanofiber membrane for wound dressings

To develop a wound dressing with effective antibacterial and biodegradable properties, polylysine (PL), nano‑silver (AgNP), and silver oxide (Ag₂O) were incorporated into polylactic acid/silk fibroin (PLA/SF) nanofibers to enhance their antibacterial activity. PLA/SF drug-loaded nanofiber films were fabricated through electrospinning, utilizing PL, AgNP, and Ag₂O as antibacterial agents. The results indicated that the inclusion of these additives improved the mobility of the molecular chains and increased crystallinity by 32.57 %. The porosity of the film decreased from 89 % to 87 %, while the liquid absorption rate and air permeability also diminished. Additionally, the contact angle increased from 78° to 92°, and water resistance improved. The film maintained adequate mechanical properties and in vitro degradation rates, which are crucial for wound dressing applications. Notably, PLA/SF nanofiber films demonstrated strong antimicrobial activity, underscoring their potential for use in the medical field. This study offers a promising approach for designing multifunctional wound dressings with enhanced antibacterial and biodegradable properties.

Polymer Applied in Hydrogel Wound Dressing for Wound Healing: Modification/Functionalization Method and Design Strategies

Hydrogel wound dressings have emerged as a promising solution for wound healing due to their excellent mechanical and biochemical properties. Over recent years, there has been significant progress in expanding the variety of raw materials used for hydrogel formulation along with the development of advanced modification techniques and design approaches that enhance their performance. However, a comprehensive review encompassing diverse polymer modification strategies and design innovations for hydrogel dressings is still lacking in the literature. This review summarizes the use of natural polymers (e.g., chitosan, gelatin, sodium alginate, hyaluronic acid, and dextran) and synthetic polymers (e.g., poly(vinyl alcohol), polyethylene glycol, Pluronic F-127, poly(N-isopropylacrylamide), polyacrylamide, and polypeptides) in hydrogel wound dressings. We further explore the advantages and limitations of these polymers and discuss various modification strategies, including cationic modification, oxidative modification, double-bond modification, catechol modification, etc. The review also addresses design principles and synthesis methods, aligning polymer modifications with specific requirements in wound healing. Finally, we discuss future challenges and opportunities in the development of advanced hydrogel-based wound dressings.

Hyaluronic Acid and Skin: Its Role in Aging and Wound-Healing Processes

Hyaluronic acid (HA) is a linear, unbranched polysaccharide classified as a glycosaminoglycan. While HA is found in various tissues throughout the body, over half of its total proportion is found in the skin. The role of HA in the skin is complex and multifaceted. HA maintains proper hydration, elasticity, and skin firmness, serving as a key extracellular matrix (ECM) component. With age, HA production gradually decreases, leading to reduced water-binding capacity, drier and less elastic skin, and the formation of wrinkles. Additionally, HA plays an active role in the wound-healing process at every stage. This review summarizes the current background knowledge about the role of HA in skin aging and wound healing. We discuss the latest applications of HA in aging prevention, including anti-aging formulations, nutricosmetics, microneedles, nanoparticles, HA-based fillers, and skin biostimulators. Furthermore, we explore various HA-based dressings used in wound treatment, such as hydrogels, sponges, membranes, and films.

Fast Wound Healing with a New Functional Hyaluronic Acid Dual Network Hydrogel

As dressings for moist wound healing, hyaluronic acid hydrogels play a significant role in maintaining moisture and promoting wound healing. However, existing hydrogel dressings are inadequate in terms of slow gelation time, weak mechanical performance, and fast degradation, which increases the risk of secondary infections during treatment. Therefore, we developed a hyaluronic acid double network hydrogel (DNH). Compared to single-network hydrogels (hydrazone and Diels-Alder), DNH shows a short gelation time (25 s) and strong mechanical properties (Young's modulus = 82 kPa). These advantages enable DNH to immediately fill the irregular shape of the wound after gelation and remain intact after being squeezed. Swelling tests indicated that DNH had a suitable swelling ratio and maintained its structural integrity after swelling. We evaluated the use of DNH as a moist dressing for full-thickness wound healing in vivo. DNH-treated wounds healed faster, with enhanced blood vessel formation and macrophage polarization than gauze-treated wounds. These findings suggest that DNH not only accelerates wound healing but also improves tissue regeneration. Therefore, DNH may be a suitable moist dressing for wound healing.

Recent advances in hyaluronic acid-based hydrogels for diabetic wound healing

Diabetic wound healing represents a complex biological challenge, often impeded by disrupted cellular processes and dysregulated inflammation, which can lead to chronic and non-healing wounds. Given the significant burden on patients and the healthcare system, there is an urgent need for advanced therapeutic strategies. Hyaluronic acid (HA)-based hydrogels have emerged as a promising solution due to their biocompatibility, biodegradability, and unique physiological functions. This review aims to provide a comprehensive overview of recent advances in HA-based hydrogels, highlighting their potential in addressing diabetic wound complications. Specifically, it examines challenges such as hyperglycemia-induced oxidative stress and impaired cellular signaling within the intricate diabetic wound microenvironment. Moreover, the review explores the composition and properties of HA, including its adhesive capabilities and role in reducing surgical trauma. Various crosslinking strategies and functional modifications are also discussed to endow HA-based hydrogels with antioxidant, antimicrobial, and growth factor-releasing capabilities. By summarizing the latest research and identifying areas for further exploration, this review contributes to the development of more effective HA-based hydrogel formulations for diabetic wound healing.

Self-healing Ppy-hydrogel promotes diabetic skin wound healing through enhanced sterilization and macrophage orchestration triggered by NIR

Non-healing diabetic foot ulcers are the knotty public health issue due to the uncontrolled bacterial infection, prolonged inflammation, and inferior vessel remodeling. In this work, polypyrrole (Ppy) was added into the hybrid hydrogel containing polyvinyl alcohol (PVA), polyethylene glycol (PEG), and hyaluronan (HA) to acquire superior mechanism and photothermal ability. The Ppy composited hybrid hydrogel could effectively kill bacteria through accumulating heat on the hydrogel surface. RNA-Seq analysis shows that the heat accumulation could enhance phagosome of macrophage and M1 activation, which further accelerate bacteria clearance. Benefitting from the bacteria clearance, macrophage could transform its phenotype to M2 in Ppy composited hybrid hydrogel group with near infrared light (NIR) stimulation. The related genes expression in keratinization, keratinocyte differentiation, and establishment of the skin barrier in the skin were up-regulated and collagen and vascular endothelial growth factor (VEGF) expression level are also enhanced. In summary, Ppy composited hybrid hydrogel could effectively solve the issues of infection and poor wound healing in diabetic foot ulcers, making it an ideal candidate dressing for the treatment of chronic wounds.

Fabrication of Chitosan/PEO/Rosmarinic acid based nanofibrous mat for diabetic burn wound healing and its anti-bacterial efficacy in mice

The pathophysiological relationship between wound healing impairment and diabetes is an intricate process. Burn injury among diabetes patients leads to neurological, vascular, and immunological abnormalities along with impaired activities of cell proliferation, collagen production, growth factors, and cytokine activities with huge bacterial infestation. In our study, we aimed to achieve a burn wound dressing material with the help of electrospun Chitosan/Polyethylene oxide/Rosmarinic acid (CS/PEO/RA) nanofibers. Chitosan is known for its biocompatibility and anti-bacterial properties; however, the electrospinning of CS requires a co-polymer such as PEO, a synthetic biodegradable polymer. With the addition of a low concentration of RA, known for its antibacterial, antioxidative nature, we enhanced the antibacterial efficacy of the electrospun nanofiber. Electrospinning CS/PEO/RA, we were able to develop a non-toxic scaffold with fibers having an average diameter of 127.035 nm, mimicking the extracellular matrix and exhibiting sustained drug release. Excellent antimicrobial activity was observed against the identified bacterial species. It showed increased wound contraction and reduced scar formation in the diabetic mice model along with rapid repair of the damaged epithelial barrier. It enhanced the production of collagen, elastin, and α-smooth muscle actin (α-SMA). Thus, it justifies itself as a diabetic burn wound dressing at low drug concentration.

A lubcan cross-linked polyethylene glycol dimethyl ether hydrogel for hyaluronic acid replacement as soft tissue engineering fillers

The structure of soft tissues is often destroyed by injury and aging. Injectable fillers eliminate the need for surgery and enhance repair. Hyaluronic acid-based hydrogels are commonly employed for their effectiveness and biocompatibility. However, hyaluronidase breaks them down quickly. Lubcan, a naturally sourced microbial extracellular polysaccharide, has demonstrated significant water absorption and retention capabilities, as well as lubricating properties comparable to those of hyaluronic acid. In this study, a novel injectable and implantable hydrogel was created from lubcan by adding polyethylene glycol diglycidyl ether as a cross-linking agent. Lubcan hydrogels exhibit exceptional thermal stability, favorable swelling behavior, in vitro degradation, compressive strength, injectability, and rheological properties, all while preserving the integrity of their three-dimensional porous structure. In vitro tests indicated that the lubcan hydrogel was non-cytotoxic, did not adhere to blood cells, and exhibited good hemocompatibility. Compared to the subcutaneous injection of commercially available hyaluronic acid hydrogels, lubcan hydrogels demonstrated superior integrity, persistence, and a softer texture in Balb/c mice after 16 weeks. At the same time, lubcan hydrogel is non-toxic to organs, does not affect blood biochemical test values, and is non-immunogenic in mice. These findings suggest that lubcan hydrogel may be a promising new superficial soft tissue filler.

Review: Advances in multifunctional hydrogels based on carbohydrate polymer and protein in the treatment of diabetic wounds

Diabetic wounds healing is often severely slowed by hyperglycemia, elevated oxidative stress, bacterial infections, and persistent inflammation. This review focuses on the development of hydrogels derived from carbohydrate polymer and protein to facilitate diabetic wound healing. We discuss the primary sources of cellulose, chitosan, hyaluronic acid, sodium alginate, collagen, and gelatin along with their advantages in the preparation of hydrogels. Based on the microenvironment of diabetic wounds, i.e., hyperglycemia, increased oxidative stress, and persistent inflammation, the application of multifunctional hydrogels in promoting diabetic wounds, including stimulus responsiveness, injection self-healing, antibacterial, antioxidant, anti-inflammatory, and synergistic effects, is discussed. We address the main challenges and future perspectives of multifunctional hydrogels based on carbohydrate polymer and protein in the treatment of diabetic wounds.

Injectable carboxymethyl chitosan/konjac glucomannan/catechin hydrogel with free radical-scavenging, antimicrobial, and pro-healing abilities for infected wound repair

Wound management presents a significant clinical challenge, requiring advanced materials to support effective healing. This study reports the development of a multifunctional injectable hydrogel wound dressing (U-COC) composed of methacrylated carboxymethyl chitosan (CMCSMA), oxidized konjac glucomannan (OKGM), and (+)-catechin hydrate (CH). The formation of the U-COC hydrogel was driven by photo-initiated polymerization, dynamic reversible Schiff base bonds, and non-covalent forces (hydrogen bond interactions, π-π stacking, and hydrophobic interactions). The in vitro antioxidant and antimicrobial test results indicated that the U-COC hydrogel could effectively scavenge oxygen central free radical PTIO· (69.8 ± 0.3%) and nitrogen central free radical DPPH· (92.8 ± 0.7%), and exhibited excellent antimicrobial effects against E. coli (89.7 ± 3.9%) and S. aureus (91.4 ± 3.4%) due to the introduction of CH. Moreover, the as-designed hydrogel wound dressing was biosafe and biodegradable, demonstrating good adhesion, wound closure, self-healing properties, and shape adaptability. This hydrogel provided an advantageous microenvironment for cell proliferation, re-epithelialization, angiogenesis, collagen deposition, and tissue repair during infected wound healing. Therefore, the combination of CMCSMA, OKGM, and CH, along with the formation mechanism of the U-COC hydrogel, represents a novel advancement in wound management technology.

A smart drug delivery microgel system with phased intervention capabilities and dual physical state of use promotes healing of diabetic infected wounds

Effectively managing infected diabetic wounds involves the elimination of bacteria, neutralization of reactive oxygen species (ROS), suppression of inflammation, and induction of angiogenesis. This study describes the development of a multifunctional hyaluronic acid (HA)-based microgel system capable of serving as either an injectable wet microgel or dry microspheres (MSs). After initially engineering Fe2+/tea polyphenol (TP) metal-polyphenol network (MPN)-functionalized HAMA MS, these particles were found to suppress inflammation and facilitate ROS scavenging. A deferoxamine (DFO)-loaded zinc-based metal-organic framework (ZIF-8@DFO) was then coated using phenylboronic acid (PBA)-functionalized ε-polylysine (PPL) to produce PPZD nanoparticles with antibacterial and pro-angiogenic properties. The dynamic loading of PPZD into MPN-functionalized MS (MMS) via boron ester bonds then yielded a pH/ROS-responsive microgel system (MMS@PPZD). PPL coating endowed the prepared materials with antimicrobial properties while mitigating cytotoxic effects resulting from the rapid release of Zn2+ and DFO in acidic micro-environments. This microgel system showed superior biocompatibility and phased intervention activities aligned with the various stages of the wound healing process in vitro and in vivo. Specifically, under acidic conditions, the system sequentially released TP, PL, Zn2+, and DFO, enabling effective ROS scavenging, suppressing inflammation, exhibiting antibacterial activity, and inducing angiogenesis. Overall, this environmentally-responsive, multifunctional, versatile microgel system offers significant promise for infected diabetic wound management.

Mussel-Inspired Hydrogel Applied to Wound Healing: A Review and Future Prospects

The application background of mussel-inspired materials is based on the unique underwater adhesive ability of marine mussels, which has inspired researchers to develop bionic materials with strong adhesion, self-healing ability, biocompatibility, and environmental friendliness. Specifically, 3, 4-dihydroxyphenylalanine (DOPA) in mussel byssus is able to form non-covalent forces on a variety of surfaces, which are critical for the mussel's underwater adhesion and enable the mussel-inspired material to dissipate energy and repair itself under external forces. Mussel-inspired hydrogels are ideal medical adhesive materials due to their unique physical and chemical properties, such as excellent tissue adhesion, hemostasis and bacteriostasis, biosafety, and plasticity. This paper reviewed chitosan, cellulose, hyaluronic acid, gelatin, alginate, and other biomedical materials and discussed the advanced functions of mussel-inspired hydrogels as wound dressings, including antibacterial, anti-inflammatory, and antioxidant properties, adhesion and hemostasis, material transport, self-healing, stimulating response, and so on. At the same time, the technical challenges and limitations of the biomimetic mussel hydrogel in biomedical applications were further discussed, and its potential solutions and future research developments in the field of biomedicine were highlighted.

Development of hyaluronic acid-based hydrogels for chronic diabetic wound healing: A review

This research delves into the advancements in chronic skin wound treatment, with a particular focus on diabetic foot ulcers, utilizing hyaluronic acid (HA)-based hydrogels. Hyaluronic acid, an integral component of the skin's extracellular matrix, plays a crucial role in process such as inflammation, angiogenesis, and tissue regeneration. Due to their three-dimensional network structure, biocompatibility, hydrophilicity, and gas exchange capabilities, HA-based hydrogels are considered highly suitable for promoting wound healing. Nonetheless, pure HA hydrogels exhibit limitations including insufficient mechanical strength and rapid release of encapsulated substances. To address these limitations, the incorporation of bioactive materials such as chitosan and collagen was investigated. This combination not only optimized mechanical strength and degradation rates but also enhanced antibacterial and anti-inflammatory properties. Furthermore, responsive hydrogel dressings were developed to adapt to the specific characteristics of the diabetic wound microenvironment, enabling on-demand drug release. These advancements present new perspectives for the treatment of diabetic foot ulcers.

Characterization of a Bioactive Chitosan Dressing: A Comprehensive Solution for Different Wound Healing Phases

Wound management has made significant advances over the past few decades, particularly with the development of advanced dressings that facilitate autolytic debridement, the absorption of wound exudate, and protection from external bacteria. However, finding a single dressing that effectively addresses all four phases of wound healing─hemostasis, inflammation, proliferation, and remodeling─remains a major challenge. Additionally, biofilms in chronic wounds pose a substantial obstacle by shielding microbes from topical antiseptics and antibiotics, thereby delaying the healing process. This study evaluates the wound-healing properties of a commercially available bioactive microfiber gelling (BMG) dressing made from chitosan alongside commercially available silver-loaded carboxymethyl cellulose (CMC-Ag) dressing, carboxymethyl cellulose dressing (CMC) and cotton gauze. In vitro testing demonstrated that the BMG dressing significantly exhibited superior fluid absorption and exudate-locking properties compared with the CMC-Ag dressing. Additionally, the BMG dressing effectively sequestered and eradicated wound-relevant pathogenic microorganisms, including drug-resistant bacteria. Its bioactive properties were further highlighted by its ability to enhance platelet-derived growth factor (PDGF) expression and sequester matrix metalloproteases (MMPs). Overall, this study highlights the effectiveness of the BMG dressing in wound management, particularly in exudate absorption and antimicrobial activity, demonstrating its relevance in wound care.

Material Design, Fabrication Strategies, and the Development of Multifunctional Hydrogel Composites Dressings for Skin Wound Management

The skin is fragile, making it very vulnerable to damage and injury. Untreated skin wounds can pose a serious threat to human health. Three-dimensional polymer network hydrogels have broad application prospects in skin wound dressings due to their unique properties and structure. The therapeutic effect of traditional hydrogels is limited, while multifunctional composite hydrogels show greater potential. Multifunctional hydrogels can regulate wound moisture through formula adjustment. Moreover, hydrogels can be combined with bioactive ingredients to improve their performance in wound healing applications. Stimulus-responsive hydrogels can respond specifically to the wound environment and meet the needs of different wound healing stages. This review summarizes the material types, structure, properties, design considerations, and formulation strategies for multifunctional hydrogel composite dressings used in wound healing. We discuss various types of recently developed hydrogel dressings, highlights the importance of tailoring their physicochemical properties, and addresses potential challenges in preparing multifunctional hydrogel wound dressings.

Bioprinted Hydrogels as Vehicles for the Application of Extracellular Vesicles in Regenerative Medicine

Three-dimensional bioprinting is a new advance in tissue engineering and regenerative medicine. Bioprinting allows manufacturing three-dimensional (3D) structures that mimic tissues or organs. The bioinks used are mainly made of natural or synthetic polymers that must be biocompatible, printable, and biodegradable. These bioinks may incorporate progenitor cells, favoring graft implantation and regeneration of injured tissues. However, the natures of biomaterials, bioprinting processes, a lack of vascularization, and immune responses are factors that limit the viability and functionality of implanted cells and the regeneration of damaged tissues. These limitations can be addressed by incorporating extracellular vesicles (EV) into bioinks. Indeed, EV from progenitor cells may have regenerative capacities, being similar to those of their source cells. Therefore, their combinations with biomaterials can be used in cell-free therapies. Likewise, they can complement the manufacture of bioinks by increasing the viability, differentiation, and regenerative ability of incorporated cells. Thus, the main objective of this review is to show how the use of 3D bioprinting technology can be used for the application of EV in regenerative medicine by incorporating these nanovesicles into hydrogels used as bioinks. To this end, the latest advances derived from in vitro and in vivo studies have been described. Together, these studies show the high therapeutic potential of this strategy in regenerative medicine.

Calcium-ion-driving assembly of polysaccharide deriving from Zizyphus jujuba to hemostatic hydrogel for treating diabetic wound

Due to good biocompatibility and biodegradable, natural polysaccharide-based hydrogels have received worldwide attentions, where polysaccharide polymers were usually chemically modified to meet the specific elastic requirements. However, it remained highly challenging to develop polysaccharide-based hydrogels with desired mechanical properties and biological functions devoid of any structural modifications. Herein, with the coordination of Ca2+ (15.0 mM), the jujuba polysaccharide (JPS, 1 %) was facilely fabricated to a hydrogel (JPS-gel) within 1 min at pH 10, where the residual proteins also played crucial roles on the assembly. The JPS-gel showed outstanding stability and mechanical properties, which were tunable by adjusting the content of Ca2+/JPS. The JPS-gel also revealed excellent biocompatibility, and could expedite the migration and proliferation of healing-related cells, angiogenesis and alleviate inflammation response. More interestingly, the JPS-gel had hemostatic capacity, where the hemostatic time and blood loss in liver incision model were 13 ± 3 s and 6.3 ± 1.6 mg after 120 s treatment with JPS-gel, respectively. All these superiorities endowed JPS-gel high performance healing in diabetic wounds (10 days). Specially, the expressions of inflammation-related genes were downregulated, but gene expressions associated with cell migration and proliferation, and angiogenesis were upregulated, thus uncovering the action mechanism of JPS-gel on accelerating wound contraction.

Enabling Targeted Drug Delivery for Treatment of Ulcerative Colitis with Mucosal-Adhesive Photoreactive Hydrogel

Ulcerative colitis (UC) is a chronic inflammatory bowel disease. UC treatments are limited by significant adverse effects associated with non-specific drug delivery, such as systematic inhibition of the host immune system. Endoscopic delivery of a synthetic hydrogel material with biocompatible gelation that can efficiently cover irregular tissue surfaces provides an effective approach for targeted drug delivery at the gastrointestinal (GI) tract. An ideal integration of synthetic material with intestinal epithelium entails an integrated and preferable chemically bonded interface between the hydrogel and mucosal surface. In this study, a photo-triggered coupling reaction is leveraged as the crosslinking platform to develop a mucosal-adhesive hydrogel, which is compatible with endoscope-directed drug delivery for UC treatment. The results demonstrated superior spatiotemporal specificity and drug pharmacokinetics with this delivery system in vivo. Delivery of different drugs with the hydrogel leads to greatly enhanced therapeutic efficacy and significantly reduced systemic drug exposure with rat colitis models. The study presents a strategy for targeted and persistent drug delivery for UC treatment.

Injectable doxorubicin-loaded hyaluronic acid-based hydrogel for locoregional therapy and inhibiting metastasis of breast cancer

Therapy and metastasis pose significant challenges for breast cancer therapy. Locoregional chemotherapy presents a promising strategy to address these dilemmas. In this study, a doxorubicin-loaded injectable hydrogel based on hyaluronic acid (DOX-MCHAgel) was fabricated for locoregional chemotherapy and inhibiting the metastasis of breast cancer. The high bio-safety of cargo-free hydrogels (MCHAgel) would enhance patient compliance. The sustained DOX release behaviors from DOX-MCHAgel (over 10 days) could reduce dosing frequency and achieve long-term therapeutic effects. The potent in vivo anti-tumor activity of DOX-MCHAgel was verified by the smallest tumor volumes, the largest number of apoptotic cells, and the strongest fluorescence intensity in TUNEL sections. Notably, the injectable DOX-MCHAgel not only greatly suppressed the growth of 4T1 tumor tissues, but also effectively curbed the liver and lung metastasis in vivo. Moreover, the survival of 4T1-tumor bearing mice was extended without obvious systemic toxicity. In brief, the novel injectable hydrogel developed in this study offers a new strategy for locoregional therapy and inhibiting metastasis of breast cancer.

Recent advances of hyaluronic acid-based materials in drug delivery systems and regenerative medicine: A review

Nowadays, diseases have a high rate of incidence and mortality worldwide. On the other side, the drawbacks of conventional modalities in the suppression of diseases have encountered serious problematic issues for the health of human beings. For instance, although various approaches have been applied for the treatment of cancer, it has an ever-increasing rate of incidence and mortality throughout the globe. Thus, there is a fundamental requirement for the development of breakthrough technologies in the inhibition of diseases. Hyaluronic acid (HA) is one of the most practical biopolymers in the suppression of diseases. HA has lots of potential physicochemical (like rheological, structural, molecular weight, and ionization, etc.) and biomedical properties (bioavailability, biocompatibility, CD44 targeting and signaling pathways, components of biological organs, mucoadhesion, immunomodulation, etc.), which made it a potential candidate for the development of breakthrough tools in pharmaceutical and biomedical sciences. The ease of surface modification (carboxylation, amidation, hydroxylation, and esterification), high bioavailability and synthesis routes, and various administration routes are considered as other merits of HA-based vehicles. These mucopolysaccharide HA-based materials have been considerably developed for use in drug delivery systems (DDSs), cancer therapy, wound healing, antiaging, and tissue engineering. This review summarizes the advantages of HA-based DDS and scaffolds in the treatment of diseases.

Regenerative effect of lyophilized dental follicle mesenchymal stem cells and platelet-rich fibrin in skin wounds in geriatric and young rats

The aim of this study was to investigate the regenerative effect of lyophilized dental follicle mesenchymal stem cells (DF-MSCs) combined with rat platelet-rich fibrin (PRF) on geriatric skin wounds. Human DF-MSCs which were isolated from the wisdom teeth of healthy donors and PRF were mixed and incubated in a 37 °C incubator for 1-2 h containing 1 million cells in 150 mg PRF. The mixture was suspended in a freeze-drying solution and then lyophilized. Wounds were created on the back skin of Wistar albino rats using a 6 mm punch. Lyophilized DF-MSCs, PRF, or PRF + DF-MSCs were applied to the wounds of rats. On the 15th day, the wound area was histopathologically evaluated in rats. Blood samples from rats were analyzed for total antioxidant status (TAOS), and inflammatory cytokine levels using ELISA. In both young and geriatric rats treated with lyophilized PRF + DF-MSCs, wound area began to significantly decrease from the 10th day compared to the untreated group (p < 0.05). Histopathological examination revealed that in the lyophilized PRF + DF-MSCs treated groups, epithelial integrity and scarless healing significantly increased compared to the untreated groups (p < 0.05). There were no significant differences in TAOS, total oxidant status (TOS), tumor necrosis factor (TNF), interleukin-6 (IL6), and hydroxyproline levels in serum samples from young rats on the 15th day. In geriatric rats, hydroxyproline (HYPS) levels were increased in the DF-MSC and PRF + DF-MSC groups (p < 0.01), TNF was significantly elevated in PRF geriatric group and IL6 was increased in the PRF group compared to the control group (p = 0.01). Lyophilized PRF + DF-MSCs, which is a shelf-stable and ready-to-use product, hold promise, especially for traumatic wounds in geriatric individuals with longer healing times.

Hyaluronic Acid-Based Therapy for Alleviating Early Lipid Peroxidation in Peripheral Nerve Compression Injury Repair

BACKGROUND

Peripheral nerve injuries compromise sensory and motor functions, severely affecting patients' quality of life. Early lipid peroxidation drives oxidative stress, disrupting the regenerative microenvironment. Hyaluronic acid (HA), an essential extracellular matrix component, shows promise in mitigating oxidative damage and fostering repair.

METHODS

In a rat sciatic nerve crush model, HA hydrogel was applied to enhance retention at the injury site. Transcriptomic analysis at 24 hours postinjury identified key pathways. In vitro assays examined HA's protective effects on Schwann cells against lipid peroxidation and oxidative stress. In vivo, HA hydrogel was administered immediately (0 hour) postcrush, followed by 4-methylumbelliferone-induced inhibition of endogenous HA synthesis and exogenous HA supplementation to clarify HA's role.

RESULTS

HA treatment reduced early lipid peroxidation, upregulated glutathione metabolism, and stimulated extracellular matrix receptor interactions, notably elevating CD44 expression. In vitro, HA lowered oxidative stress and maintained Schwann cell viability. In vivo, early HA intervention mitigated muscle atrophy, preserved myelin sheaths, and improved Sciatic Functional Index scores compared to delayed or untreated controls. Inhibiting endogenous HA synthesis impaired recovery, which was partially reversed by exogenous HA.

CONCLUSIONS

Early HA intervention modulates lipid peroxidation and oxidative stress via the HA/CD44 axis, establishing a supportive microenvironment for peripheral nerve regeneration and functional recovery. These findings underscore the potential of HA-based strategies to curb early lipid peroxidation, thereby expediting nerve repair and accelerating regeneration.

Recent Advances in Polysaccharide-Based Hydrogels for Tumor Immunotherapy

Immunotherapy has revolutionized cancer treatment and led to a significant increase in patient survival rates and quality of life. However, the effectiveness of current immunotherapies is limited by various factors, including immune evasion mechanisms and serious side effects. Hydrogels are a type of medical material with an ideal biocompatibility, variable structure, flexible synthesis method, and physical properties. Hydrogels have long been recognized and used as a superior choice for various biomedical applications. The fascinating results were derived from both in vitro and in vivo models. The rapid expansion of this area suggests that the principles and uses of functionalized polysaccharides are transformative, motivating researchers to investigate novel polysaccharide-based hydrogels for wider applications. Polysaccharide hydrogels have proven to be a practicable delivery strategy for tumor immunotherapy due to their biocompatibility, biodegradability, and pronounced bioactive characteristics. This study aims to examine in detail the latest developments of polysaccharide hydrogels in tumor immunotherapy, focusing on their design, mechanism of action, and potential therapeutic applications.

Investigation of the Antibacterial Activity of ZnO-Loaded Alginate/Hyaluronic Acid Aerogels for Wound Dressing Applications

The prevalence of bacterial infections in wounds is a significant challenge to successful wound healing. This study investigates the antibacterial effect of hyaluronic acid and alginate aerogel loaded with zinc oxide nanoparticles as a potential dressing for wound healing. The aerogel composite was synthesized via supercritical gel drying and characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and nitrogen porosimetry. The absorptivity of the prepared aerogel was evaluated, as well as the antibacterial activity, which was evaluated against common wound pathogens, including Staphylococcus aureus and Escherichia coli, using the agar diffusion method. The results show the effective antibacterial properties of the prepared hydrogel and aerogel. Furthermore, the results show water absorption ability of 5791 and 1585% for loaded and unloaded aerogels, respectively. The ZnO released from the aerogel exhibited a rapid release followed by a slow and sustained release. These findings highlight the potential of aerogels based on hyaluronic acid and alginate and loaded with zinc oxide nanoparticles as an innovative antibacterial wound dressing material, which is expected to improve wound healing and reduce the risk of bacterial infections.

Treatment of Acute Ulcerative Colitis with Zinc Hyaluronate in Mice

Ulcerative colitis (UC) is a type of inflammatory bowel disease arising from numerous factors, while UC patients face insufficient treatment options and a high incidence of adverse reactions to the current therapies. As a functional food additive, hyaluronic acid plays a certain role in intestinal repair. In this study, we constructed a mouse model of dextran sulfate sodium (DSS)-induced UC to examine the effects and underlying mechanisms of action of zinc hyaluronate (ZnHA) on the pathogenesis of UC. ZnHA effectively alleviated key clinical UC symptoms, such as weight loss, loose stools, and bloody stools. Mechanistically, ZnHA attenuated the expression of inflammatory factors, such as tumor necrosis factor-α, interleukin (IL)-6, and myeloperoxidase while upregulating the expression of IL-10. Furthermore, through intestinal flora and short-chain fatty acid analyses, ZnHA was found to promote propionic acid production by enriching beneficial bacteria. ZnHA simultaneously enhanced the expression of tight junction proteins, specifically ZO-1 and occludin, thereby restoring intestinal barrier function. Overall, our findings elucidate the therapeutic potential of ZnHA in treating acute UC by inhibiting intestinal inflammation and regulating flora, while also providing further theoretical support for development of hyaluronic acid to treat this disease.

Effects of Hydration and a Hyaluronic Acid-Containing Lozenge on Voice Parameters in Conjunction With a Vocal Loading Test

PURPOSE

This study explores the effects of water intake and a hyaluronic acid (HA)-containing lozenge on acoustic measurements and vocal oscillation patterns investigated after a vocal loading test (VLT).

METHOD

Ten healthy subjects (five females, five males) read out loud a standardized text for 10 min at a target level of 80 dB(A), measured 30 cm from the mouth, under three conditions but each after fasting for 2 hr: (a) drinking 0.7 l of water, (b) sucking an HA-containing lozenge, and (c) neither of both before the VLT. The dysphonia severity index (DSI) was assessed before and after the reading task. Additionally, high-speed videolaryngoscopy (HSV), electroglottography, and an audio signal during sustained phonation on the vowel /i/ before and after the VLT were analyzed. The glottal area waveform was derived from the HSV footage.

RESULTS

DSI values decreased for the H2O and HA group, but reached statistical significance only for the H2O condition, while remaining stable for the control condition. These DSI decreases were driven by increases in minimum sound pressure level intensity (Imin)-again with statistical significance solely for the water intake intervention. Statistically nonsignificant changes were observed regarding periodicity and perturbation parameters across all conditions. No phase differences or aperiodicities were apparent in the phonovibrograms.

CONCLUSIONS

Hydration and an HA lozenge did not significantly alter vocal fold biomechanics after a VLT. However, the decrease in DSI values with increased Imin suggests a reduced vocal capacity for the H2O condition.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.28271285.

Synthetic nanointerfacial bioengineering of Ti implants: on-demand regulation of implant-bone interactions for enhancing osseointegration

Titanium and its alloys are the most commonly used biometals for developing orthopedic implants to treat various forms of bone fractures and defects, but their clinical performance is still challenged by the unfavorable mechanical and biological interactions at the implant-tissue interface, which substantially impede bone healing at the defects and reduce the quality of regenerated bones. Moreover, the impaired osteogenesis capacity of patients under certain pathological conditions such as diabetes and osteoporosis may further impair the osseointegration of Ti-based implants and increase the risk of treatment failure. To address these issues, various modification strategies have been developed to regulate the implant-bone interactions for improving bone growth and remodeling in situ. In this review, we provide a comprehensive analysis on the state-of-the-art synthetic nanointerfacial bioengineering strategies for designing Ti-based biofunctional orthopedic implants, with special emphasis on the contributions to (1) promotion of new bone formation and binding at the implant-bone interface, (2) bacterial elimination for preventing peri-implant infection and (3) overcoming osseointegration resistance induced by degenerative bone diseases. Furthermore, a perspective is included to discuss the challenges and potential opportunities for the interfacial engineering of Ti implants in a translational perspective. Overall, it is envisioned that the insights in this review may guide future research in the area of biometallic orthopedic implants for improving bone repair with enhanced efficacy and safety.

A dissolving microneedle patch loaded with plumbagin/hydroxypropyl-β-cyclodextrin inclusion complex for infected wound healing

Treating infected wounds is facing a serious challenge due to the rapid spread of antibiotic resistance worldwide. In the search for novel antimicrobial drugs, natural products often serve as a crucial resource. Plumbagin (PLB) is the most important natural active ingredient in the root of Plumbago zeylanica L. known for its excellent antibacterial ability. However, the application of PLB is limited because of its poor water solubility, instability, and tendency to sublimate. In this study, we propose a solution by designing a hyaluronic acid (HA)/polyvinylpyrrolidone (PVP) dissolving microneedle patch loaded with PLB/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex. PLB was encapsulated into the cavity of HP-β-CD to improve its solubility and stability using the neutralization agitation method. The formation of the inclusion complex significantly increased the water solubility of PLB to 1350 ± 6.8 μg/mL, which is 17 times higher than its original value of 79.3 ± 1.7 μg/mL. The encapsulation efficiency was found to be 94.82 ± 3.34 %. In vitro drug release studies, PLB microneedles loaded with PLB/HP-β-CD inclusion complex rapidly released into PBS within 15 min. Furthermore, the PLB microneedles exhibited strong antibacterial activity against Staphylococcus aureus (S. aureus) both in vivo and in vitro. They also remarkably accelerated the healing of infected wounds in mice by enhancing collagen deposition and re-epithelialization, reducing inflammation, and stimulating angiogenesis. Overall, this multifunctional microneedle patch shows promising potential for clinical applications in the healing of infected wounds.

Systematic preparation of animal-derived glycosaminoglycans: Research progress and industrial significance

Impurities and isomerized polysaccharides affect the analytical accuracy of glycosaminoglycans (GAGs) structure and bioactivity, hindering their application in food and medicine. Preparing homogeneous GAGs components is essential for exploring structure-potency relationships and facilitating industrial production. This review primarily summarizes research on animal-derived GAGs preparation over the past five years, standardizing the preparation process into four operational units: pre-extraction treatment, extraction of crude polysaccharides, refinement of crude polysaccharides, and separation of GAGs components. Analyzed for scientific research and industrial production, the principles and application conditions of traditional means and novel techniques to preparing GAGs are comprehensively emphasized, exploring the effects of different treatments on biological activity and structure. Current challenges and development trends are illuminated. This review aims to lay a foundation for the in-depth study of GAGs structure, bioactivity, and function, providing theoretical references for the comprehensive utilization of animal raw materials and the development of animal polysaccharide deep-processing industries.

A tranexamic acid-functionalized acellular dermal matrix sponge co-loaded with magnesium ions: Enhancing hemostasis, vascular regeneration, and re-epithelialization for comprehensive diabetic wound healing

Excessive inflammation, accumulation of wound exudate, and blood seepage are common in diabetic wounds, hindering cell proliferation and disrupting tissue remodeling, leading to delayed healing. This study presents a multifunctional sponge scaffold (P5T3@Mg) created by combining an acellular dermal matrix with tranexamic acid and MgO nanoparticles, designed for hemostatic and anti-inflammatory effects. The P5T3@Mg scaffold effectively absorbs wound fluid while promoting healing. In vivo and in vitro hemostasis experiments demonstrate that the P5T3@Mg sponge exhibits excellent hydrophilicity, enhancing blood absorption at the wound site, inhibiting fibrinolysis, and expediting hemostasis. Additionally, the sustained release of Mg2+ from the P5T3@Mg sponge promotes collagen deposition and angiogenesis in diabetic rat wounds, suppressing chronic inflammation and accelerating tissue remodeling and repair.

Glucose-fueled cationic nanomotors for promoting the healing of infected diabetic wounds

Hyperglycemia-promoted bacterial infection will seriously exacerbate diabetic wounds, and its current clinical treatments are suffering from the adverse effects associated with off-target, bacterial resistance, and glycemic fluctuation. Herein, we present a kind of glucose-fueled cationic nanomotors capable of remarkably enhancing antibacterial efficacy, and thus expediting diabetic wound healing. The nanomotors have positively charged surfaces, and consist of mesoporous bowl-shaped polydopamine nanoparticles grafted with quaternized polymer brushes and coupled with glucose oxidase (GOx) and catalase (CAT). Stemming from the GOx-CAT cascade reaction in diabetic wound microenvironment, they can perform robust chemotactic motion towards both high glucose regions, where bacteria proliferation predominantly occurs, and elevated H2O2 levels, which bacterial metabolism produced. This enables the nanomotors to facilitate targeted migration towards bacteria-rich regions and simultaneous downregulation of glycemic levels, as well as to significantly enhance the electrostatic interaction between antibacterial components and bacteria. Consequently, the nanomotors exhibit amplified contact-killing effects of their attached cationic molecules, leading to an almost 10-fold enhancement in antibacterial efficacy compared to previous counterparts. The in vivo experiments approved that the nanomotors demonstrated the accelerated healing of infected diabetic wounds by S. aureus and biosafety. The results herein provide an insight into the clinical treatment of infected diabetic wounds.

Development of a Chitosan-Silver Nanocomposite/β-1,3-Glucan/Hyaluronic Acid Composite as an Antimicrobial System for Wound Healing

An ideal wound dressing should be biocompatible, exhibit high antibacterial activity, and promote blood coagulation in the wound. In this study, we used chitosan as a multifunctional template to synthesize silver nanoparticles embedded in chitosan (Ag NP@CHI), which were then combined with β-1,3-glucan/hyaluronic acid (HA) to form an Ag NP@CHI/β-1,3-glucan/HA composite material with biocompatibility, wound healing-promoting properties, and antibacterial activity. A high concentration of chitosan led to the formation of smaller crystalline structures of Ag NPs and improved their dispersion within the chitosan matrix, but decreased their antibacterial potency. The Ag NP@CHI prepared with 1.0 mg/mL chitosan had the smallest particle size and good antibacterial activity. Compared to Ag NP@CHI, the prepared Ag NP@CHI/β-1,3-glucan/HA composite significantly enhanced biocompatibility, cell migration, hemocompatibility, and blood coagulation, with a minor reduction in antibacterial efficiency due to restricted ionic silver release and diffusion. With its high biocompatibility, hemocompatibility, promotion of blood coagulation and wound healing, and antibacterial efficiency, Ag NP@CHI@β-1,3-glucan/HA demonstrates potential as a wound healing composite in the future.

Inducible engineering precursor metabolic flux for synthesizing hyaluronic acid of customized molecular weight in Streptococcus zooepidemicus

BACKGROUND

Hyaluronic acid (HA) is extensively employed in various fields such as medicine, cosmetics, food, etc. The molecular weight (MW) of HA is crucial for its biological functions. Streptococcus zooepidemicus, a prominent HA industrial producer, naturally synthetizes HA with high MW. Currently, few effective approaches exist for the direct and precise regulation of HA MW through a one-step fermentation process, and S. zooepidemicus lacks metabolic regulatory elements with varying intensities. The ratio of HA's precursors, UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-glucuronic acid (UDP-GlcA), is critical for the extension and release of HA. An imbalance in the precursor proportions for HA synthesis leads to a significant decrease in HA MW, indicating that controlling the precursor ratio may serve as a potential method for regulating HA MW.

RESULTS

In this study, the type and concentration of carbon sources were manipulated to disrupt the balance of precursor supply. Based on the results, it was speculated that the transcription level of hasE, which may connect the two HA synthesis precursors, is positively correlated with HA MW. Consequently, an endogenous expression component library for S. zooepidemicus was constructed, comprising 32 constitutive and 4 inducible expression elements. The expression of hasE was subsequently regulated in strain SE0 (S12 ΔhasE) using two constitutive promoters of differing strengths. The recombinant strain SE1, in which hasE was controlled by the stronger promoter PR31, produced HA with a MW of 1.96 MDa. In contrast, SE2, utilizing the weaker promoter PR22, synthesized shorter HA with a MW of 1.63 MDa, thereby verifying the hypothesis. Finally, to precisely regulate HA MW according to specific demands, an efficient sucrose-induced expression system was screened and employed to control the transcription level of hasE, obtaining recombinant strain SE3. When induced with sucrose concentrations of 3, 5-10 g/L, the HA MW of SE3 reached 0.78 to 1.77 MDa, respectively.

CONCLUSIONS

Studies on regulating the balance of the HA precursor substances indicate that an oversupply of either UDP-GlcNAc or UDP-GlcUA can reduce HA MW. The hasE gene serves as a crucial regulator for maintaining this balance. Precise regulation of hasE transcription was achieved through an efficient inducible expression system, enabling the customized production of HA with specific MW. The HA MW of strain SE3 can be accurately manipulated by adjusting sucrose concentration, establishing a novel strategy for customized HA fermentation.

A composite dressing combining ultralong hydroxyapatite nanowire bio-paper and a calcium alginate hydrogel accelerates wound healing

An acute wound is the most common type of skin injury. Developing wound dressings with excellent mechanical properties, wound protection, comfort, angiogenic capacity and therapeutic effects is significant for effective treatments, yet remains challenging. Herein, we have designed a novel HAP-Alg composite dressing comprising a complementary ultralong hydroxyapatite (HAP) nanowire bio-paper and calcium alginate hydrogel. The HAP bio-paper assembled by ultralong HAP nanowires, in contrast to typical brittle HAP bio-ceramics, exhibits a highly flexible and interwoven structure to enhance the mechanical and protective performance of an alginate hydrogel, and the alginate matrix creates a moist environment for skin regeneration. Therefore, the HAP-Alg composite dressing presents good mechanical properties and high resistance to swelling and shrinkage, along with a reliable bacterial shielding ability. In addition, its moisturizing effect can deliver bioactive calcium ions to promote angiogenesis, accelerate re-epithelialization and reduce scar formation. In vitro studies reveal that the HAP-Alg composite dressing has excellent biocompatibility, promotes cell migration and angiogenesis, and enhances calcium ion influx. In vivo wound models further prove the ability of the HAP-Alg composite dressing to accelerate wound closure, enhance collagen deposition, and induce neovascularization. This work demonstrates that the HAP-Alg composite dressing offers a promising wound dressing for acute wound treatment and protection.

Hydrogel-Forming Microneedles and Applications in Interstitial Fluid Diagnostic Devices

Hydrogel-forming microneedles are constructed from or coated with polymeric, hydrophilic materials that swell upon insertion into the skin. Designed to dissolve or disintegrate postinsertion, these microneedles can deliver drugs, vaccines, or other therapeutics. Recent advancements have broadened their application scope to include the collection, transport, and extraction of dermal interstitial fluid (ISF) for medical diagnostics. This review presents a brief introduction to the characteristics of dermal ISF, methods for extraction and sampling, and critical assessment of the state-of-the-art in hydrogel-forming microneedles for ISF diagnostics. Key factors are evaluated including material composition, swelling behavior, biocompatibility, and mechanical strength necessary for effective microneedle performance and ISF collection. The review also discusses successful examples of dermal ISF assays and microneedle sensor integrations, highlighting notable achievements, identifying research opportunities, and addressing challenges with potential solutions. Despite the predominance of synthetic hydrogels in reported hydrogel-forming microneedle technologies due to their favorable swelling and gelation properties, there is a significant variety of biopolymers and composites reported in the literature. The field lacks consensus on the optimal material, composition, or fabrication methods, though emerging evidence suggests that processing and fabrication techniques are critical to the performance and utility of hydrogel-forming microneedles for ISF diagnostics.

Naturally Inspired Tree-Ring Structured Dressing Provides Sustained Wound Tightening and Accelerates Closure

Mechanically regulated wound dressings require a rational combination of contraction and adhesion functions as well as balancing exudate-induced swelling issues. However, many of the reported dressings face the dilemma of impaired function and impeded wound self-contraction due to fluid-absorbing swelling. In this study, inspired by the tree ring, a core-ring structured hydrogel dressing capable of mechanical modulation is designed, and prepare it using a simple two-step photopolymerization process. The core covers the center of the wound, contracts spontaneously at body temperature to generate a contractile force of 3.4 kPa, and resists swelling. Meanwhile, the ring adheres to the normal epidermis around the wound and transfers the contraction stress to the wound edge. The integration of a functionally independent core and ring ultimately achieves effective wound traction and avoids dressing swelling. In murine and porcine skin wound-healing models, this hydrogel with a closely connected core and ring promotes healing by accelerating epidermal closure (50% closure in mouse skin on day 2, 85% closure in pig skin on day 8), collagen deposition, vascular maturation, and extracellular matrix remodeling. These results can guide further research on mechanical force modulation in wound healing, with the potential for clinical translation.

Tailoring membrane technology with galactomannan for enhanced biocompatibility and antibacterial action

In this study, we elaborated advanced asymmetric membranes using polyvinyl alcohol (PVA) and a galactomannan (GA) derived from Delonix regia seeds, a blend known for its biocompatibility properties. These membranes, crosslinked with sulfosuccinic acid (SSA), exhibited remarkable enhancements in various crucial aspects for biomedical applications, in particular provides antibacterial properties. The incorporation of GA leads to the formation of globular regions, enhancing crosslinking and swelling properties. Increasing GA content results in membranes with enhanced biodegradation, reduced mechanical resistance, and increased elongation at break. The chemical composition of these membranes actively stimulates the metabolism of fibroblasts, osteoblasts, and to a lesser extent, monocytes, promoting cell proliferation particularly at GA contents between 10 and 20 %. Notably, the membrane containing 20 wt% GA demonstrates anti-inflammatory effects by reducing MCP-1 cytokine secretion without compromising tissue repair capacity, as TGF-ß secretion remains unaffected in human monocytes. This multifaceted approach underscores the potential of these membranes in biomedical applications, particularly in wound healing and tissue engineering.

Hydrogels and hydrogel-based drug delivery systems for promoting refractory wound healing: Applications and prospects

Refractory wounds represent a significant health concern that presents considerable challenges within clinical practice. The healing process of refractory wounds, which involves various cell types and biologically active molecules, is dynamically influenced by multiple factors, including diabetes, infections, and inflammation. Owing to their hydrophilicity, biocompatibility, and capacity for drug loading, hydrogels have emerged as promising and innovative biomaterials for enhancing wound healing. In recent decades, hydrogels with inherent therapeutic properties have been identified. Moreover, advanced hydrogel-based drug delivery systems have been developed to facilitate the sustained and controlled release of therapeutic agents at the site of refractory wounds. This review aims to summarize recent advancements and applications of hydrogels, including those with intrinsic therapeutic properties and hydrogel-based drug delivery systems, in the treatment of refractory wounds. Additionally, we discuss the limitations associated with hydrogel applications and propose future perspectives, which will lead to ongoing efforts to optimize hydrogels as ideal biomaterials for refractory wound healing.

Platinum nanozyme embedded in hyaluronate with multifunctional attributes synergistically promoting tracheal fistula healing

Respiratory tract fistulas, including tracheal and bronchial fistulas, usually cause prolonged hospitalization with developed complications and even death, while respiratory tract fistula healing remains challenging. Exploring effectiveness and mechanism in animal systems using well-designed bio-nanomaterials will improve our understanding of fistula management. Hyaluronate (hyaluronan or hyaluronic acid) has been widely studied as a promising coating material for bio-nanomaterials in treatment applications. Herein, by combining the intrinsic bioactivities of sodium hyaluronate (SHA) and the enzyme-like activities of platinum (Pt) nanoparticles (NPs), obtained SHA-PtNPs defined as nanozymes (Enzyme-like nanomaterials) have been proposed to treat tracheal fistulas. Results reveal that introducing SHA endows the fabrication of PtNPs with dispersibility, small particle size (3.7 nm), stability, etc. On the other hand, SHA-PtNPs present high catalase-like (3320 U/g), superoxide dismutase-like activities (129,000 U/g), and hydroxyl radicals elimination capacity, thereby exerting excellent reactive oxide species scavenging ability. We have systematically verified the above properties of SHA-PtNPs in vitro. SHA-PtNPs show outstanding biocompatibility, promote cell proliferation and migration, and have considerable hemocompatibility and hemostasis. Afterward, rabbit tracheal fistula models that were treated with SHA-PtNPs in vivo showed a significant improvement in the closure of the fistulas and an increase in quality. This was evident through a substantial decrease in inflammation, increased angiogenesis, stimulation of re-epithelialization, and highly ordered alignment of collagen fibers. No significant side effects were observed. In summary, this work initiates an in vivo treatment for tracheal fistula models by taking advantage of both naturally sourced polysaccharides and nanozymes.

Nanoscale Systems for Local Activation of Hypoxia-Inducible Factor-1 Alpha: A New Approach in Diabetic Wound Management

Chronic wounds in diabetic patients experience significant clinical challenges due to compromised healing processes. Hypoxia-inducible factor-1 alpha (HIF-1α) is a critical regulator in the cellular response to hypoxia, enhancing angiogenesis and tissue restoration. Nevertheless, the cellular response to the developed chronic hypoxia within diabetes is impaired, likely due to the destabilization of HIF-1α via degradation by prolyl hydroxylase domain (PHD) enzymes. Researchers have extensively explored HIF-1α activation as a potential pathway for diabetic wound management, focusing mainly on deferoxamine (DFO) as a potent agent to stabilize HIF-1α. This review provides an update of the other recent pharmacological agents managing HIF-1α activation, including novel PHD inhibitors (roxadustat and daprodustat) and Von Hippel-Lindau protein (VHL) antagonists, which could be potential alternatives for the local treatment of diabetic wounds. Furthermore, it highlights how localized delivery via advanced nanostructures can enhance the efficacy of these novel therapies. Importantly, by addressing these points, the current review can offer a promising area for research. Given that, these novel drugs have minimal applications in diabetic wound healing, particularly in the context of local application through nanomaterials. This gap presents an exciting opportunity for further investigation, as combining these drugs with localized nanotechnology could avoid undesired systemic side effects and sustain drug release within wound site, offering a transformative platform for diabetes wound treatment.

Injectable Nanocomposite Hydrogel with Synergistic Biofilm Eradication and Enhanced Re-epithelialization for Accelerated Diabetic Wound Healing

Diabetic wounds remain a critical clinical challenge due to their harsh microenvironment, which impairs cellular function, hinders re-epithelialization and tissue remodeling, and slows healing. Injectable nanocomposite hydrogel dressings offer a promising strategy for diabetic wound repair. In this study, we developed an injectable nanocomposite hydrogel dressing (HDL@W379) using LAP@W379 nanoparticles and an injectable hyaluronic acid-based hydrogel (HA-ADH-ODEX). This dressing provided a sustained, pH-responsive release of W379 antimicrobial peptides, effectively regulating the wound microenvironment to enhance healing. The HDL@W379 hydrogel featured multifunctional properties, including mechanical stability, injectability, self-healing, biocompatibility, and tissue adhesion. In vitro, the HDL@W379 hydrogel achieved synergistic biofilm elimination and subsequent activation of basal cell migration and endothelial cell tube formation. Pathway analysis indicated that the HDL@W379 hydrogel enhances basal cell migration through MEK/ERK pathway activation. In methicillin-resistant Staphylococcus aureus (MRSA)-infected diabetic wounds, the HDL@W379 hydrogel accelerated wound healing by inhibiting bacterial proliferation and promoting re-epithelialization, regenerating the granulation tissue, enhancing collagen deposition, and facilitating angiogenesis. Overall, this strategy of biofilm elimination and basal cell activation to continuously regulate the diabetic wound microenvironment offers an innovative approach to treating chronic wounds.

Ketoprofen Associated with Hyaluronic Acid Hydrogel for Temporomandibular Disorder Treatment: An In Vitro Study

Temporomandibular disorders (TMD) are a public health problem that affects around 12% of the global population. The treatment is based on analgesics, non-steroidal anti-inflammatory, corticosteroids, anticonvulsants, or arthrocentesis associated with hyaluronic acid-based viscosupplementation. However, the use of hyaluronic acid alone in viscosupplementation does not seem to be enough to regulate the intra-articular inflammatory process. So, we propose to develop and evaluate the physicochemical and biological properties in vitro of hyaluronic acid hydrogels (HA) associated with ketoprofen (KET) as a new therapeutic treatment for TMD. The hydrogels were synthesized with 3% HA and 0.125, 0.250, 0.500, or 1% KET. Physicochemical analyses of Attenuated Total reflectance-Fourier transform infrared spectroscopy (FTIR), Thermogravimetry (TGA), Rheology by Frequency, Amplitude sweeps, temperature ramp, and scanning electron microscopy (SEM) were performed with or without sterilization and cycled. Cytocompatibility and genotoxicity (micronucleus assay) were performed in mouse macrophages (RAW 264-7) for 24 h. Results: FTIR spectrum showed characteristic absorptions of HA and KET. In the TGA, two mass loss peaks were observed, the first representing the water evaporation at 30 and 100 °C, and the second peaks between 200 and 300 °C, indicating the degradation of HA and KET. Rheology tests in the oscillatory regime classified the hydrogels as non-Newtonian fluids, time-dependent, and thixotropic. Mouse macrophages (RAW 264-7) presented viability of 83.6% for HA, 50.7% for KET, and 92.4%, 66.1%, 65.3%, and 87.7% for hydrogels, in addition to the absence of genotoxicity. Conclusions: Hyaluronic acid associated with ketoprofen shows satisfactory physicochemical and biological properties for use as viscosupplementation. As a limiting point of this study, further research is needed to evaluate the pharmacodynamic, toxicological, and pharmacokinetic characteristics of a complete organism.

Effect of hyaluronic acid on the formation of acellular dermal matrix-based interpenetrating network sponge scaffolds for accelerating diabetic wound healing through photothermal warm bath

Adequate vascularization essential for delivering nutrients critical to wound healing, yet impaired angiogenesis is a major barrier in diabetic wound repair. This study investigates the impact of hyaluronic acid on interpenetrating network sponge scaffolds derived from an acellular dermal matrix, with the aim of enhancing vascularization and healing of diabetic wounds via photothermal warm bath therapy. We prepared three-dimensional porous sponges (H1P4D2@DFO) using molecular interpenetration and ion crosslinking of porcine acellular dermal matrix (PADM), hyaluronic acid, and polydopamine nanoparticles loaded with deferoxamine mesylate (PDA@DFO). This resulting extracellular matrix-based sponge demonstrated properties suitable for wound repair, including high cell adhesion, biocompatibility, bioactivity, porosity (85 %), and water absorption (4500 %). The near-infrared (NIR) photothermal effect of PDA@DFO and the sustained release of deferoxamine mesylate (DFO) enhanced wound vascularization within the wound site. These findings suggest that our sponge scaffold can simulate skin-like structures and establish a supportive microenvironment conducive to microvascular reconstruction. By combining the photothermal warm bath approach with the scaffold's tailored 3D structure, we observed enhanced angiogenesis and accelerated diabetic wound healing, indicating potential clinical applications of these scaffolds in chronic wound management.