Chronic Wound Dressings Research Articles

Multifunctional poly(ether‐urethane) elastomer based on dynamic phenol-urethane and disulfide bonds: Simultaneously showing superior toughness, self-healing, shape memory, antibacterial, and antioxidative properties

Multifunctional polymers are highly desirable for developing smart materials in medical applications. This study proposed a facile strategy to fabricate a new multifunctional poly(ether‐urethane) incorporating disulfide bonds and phenol-urethane bonds (PEU−TS). The distinctive feature of the designed PEU−TS elastomers was the presence of abundant phenolic hydroxyl groups, dynamic aromatic disulfide bonds, phenol-urethane bonds, and multiple H-bonds between urethane groups and tannic acid (TA) molecules, which endowed the materials with superior antibacterial and antioxidative activities, self‐healing capabilities, and shape memory functions. Furthermore, the phenol-carbamate crosslinked networks enhanced the tensile properties and improved the biostability of the elastomers. Biocompatibility evaluation further demonstrated that networked PEU−TS composites possessed favorable cell viability and high cytocompatibility. The multifunctional PEU−TS elastomers with robust tensile properties hold great potential for application in durable implants and chronic wound dressings. This elaborate design could inspire the development of multifunctional PU materials over wide medical applications.

Smart Dressings and Their Applications in Chronic Wound Management.

During chronic wound healing, the inflammatory phase can endure for extended periods, heavily impeding or halting the process. Regular inspections and dressing changes are crucial. Modern dressings like hydrogels, hydrocolloids, and foam provide protection and an optimal healing environment. However, they have limitations in offering real-time wound bed status and healing rate. Evaluation relies heavily on direct observation, and passive dressings fail to identify subtle healing differences, preventing adaptive adjustments in biological factors and drug concentrations. In recent years, the clinical field recognizes the value of integrating intelligent diagnostic tools into wound dressings. By monitoring biomarkers linked to chronic wounds' inflammatory state, real-time data can be captured, reducing medical interventions and enabling more effective treatment plans. This fosters innovation in chronic wound care. Researchers have developed smart dressings with sensing, active drug delivery, and self-adjustment capabilities. These dressings detect inflammatory markers like temperature, pH, and oxygen content, enhancing drug bioavailability on the wound surface. As wound healing technology evolves, these smart dressings hold immense potential in chronic wound care and treatment. This comprehensive review updates our understanding on the role and mechanism of action of the smart dressings in chronic refractory wounds by summarizing and discussing the latest research progresses, including the intelligent monitoring of wound oxygen content, temperature, humidity, pH, infection, and enzyme kinetics; intelligent drug delivery triggered by temperature, pH, near-infrared, and electricity; as well as the intelligent self-adjustment of pressure and shape. The review also delves into the constraints and future perspectives of smart dressings in clinical settings, thereby advancing the development of smart wound dressings for chronic wound healing and their practical application in clinical practice.

CeO2-loaded PVA/GelMA core-shell nanofiber membrane to promote wound healing

Chronic wounds are a significant health issue due to various pathogenic abnormalities that hinder the healing process. Nanofiber membranes, with their favorable conductivity for cell growth, proliferation, and adhesion, offer immense potential for effective chronic wound healing. In this study, we utilized the coaxial electrospinning method to synthesize core-shell structured nanofiber membranes for chronic wound healing. To obtain superior nanofiber membranes, we modified the shell part of the electrospun nanofiber by combining gelatin methacrylate (GelMA) with cerium oxide (CeO2). The results show that these nanofibers exhibit promising wound healing properties, including ideal hydrophilicity, swelling ratio, porosity, mechanical properties, antibacterial activity, and fibroblast cell viability. With the addition of 3 % w/v CeO2 nanoparticles (PGCe-3 CL sample), the nanofiber membrane had a 53.7° water contact angle, 384.47 % swelling ratio, 83.91 % porosity, and 8.49 MPa tensile strength, which are optimal for the wound healing process. The PGCe-3 CL sample also demonstrated increased antibacterial activity, reducing bacterial colonies by up to 88.46 % for S. aureus and 93.14 % for E. coli compared to PG-CL and PGCe-1.5 CL. Furthermore, the cell viability test showed that the nanofiber membranes are non-toxic to human dermal fibroblast cells and significantly enhance cell proliferation compared to other samples. Accordingly, the synthesized nanofiber membranes loaded with nano CeO2 in this study show promising performance as suitable dressings for chronic wounds. Moreover, the findings of this study provide valuable insights for developing more effective and innovative materials for chronic wound healing.

Cobalt-phenolic nanoparticles-driven self-assembly of hyaluronic acid hydrogels providing a multifactorial approach for chronic wound management

Chronic wounds are persistent non-healing lesions whose complex management is due to the interplay of multiple factors promoting chronicity, such as oxidative stress, overexpressed enzyme activities impeding the tissue repair and bacterial contamination. Currently marketed chronic wound dressings are designed mainly to absorb wound exudate, and at most to release antimicrobial agents, usually ionic silver. However, an effective wound repair requires addressing the multifactorial nature of the wound in a holistic approach. This study explores the potential of metal phenolic network (MPN) nanoparticles (NPs), comprised of epigallocatechin gallate (EGCG) and cobalt, as active agents and structural elements in wound dressings. The MPN NPs were able to generate reactive oxygen species (ROS), disturb bacterial membrane, and inhibit the biofilm of both gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa. Owing to the high interfacial activity of their phenolic shells, the NPs drove the self-assembly of thiolated hyaluronic acid (THA) hydrogels featuring injectability, self-healing, stimuli-responsive NPs delivery in wound microenvironment, and control over deleterious enzyme activities, oxidative stress and bacterial colonisation. Specifically, the hydrogels inhibited matrix metalloproteinases (MMPs) and myeloperoxidase (MPO) by 60 and 80 %, respectively, and achieved 4-log reduction of S. aureus and 2-log reduction of P. aeruginosa concentrations. Finally, the hydrogels were in-vivo validated in a mouse animal model, showing lack of toxicity and similar wound healing efficiency as an antibiotic-containing commercial product.

Promotion and monitor wound healing by anthocyanin enhanced light curing ε-poly-l-lysine hydrogel encapsulated Cu-MOF

Drug-resistant bacterial infections and biofilm formation have long posed significant challenges to public health, particularly in the context of chronic wound healing. In this study, the CuHspMOF were derived from copper and hesperitin (Hsp). The photocurable Epsilon-poly-l-lysine (EPLMA) and blueberry anthocyanin (BA) were synthesized through free radical polymerization. The multifunctional EB@CuHsp hydrogel exhibits excellent photothermal effect. One of the key features of the EB@CuHsp hydrogel is its ability to monitor the healing environment through color changes in response to variations in pH. This property allows for real-time assessment of the wound’s pH levels, reflecting the body fluid’s pH range during the healing process (pH 5–9). The hydrogel components work synergistically to facilitate wound healing. The EPLMA, with its positively charged, could captures bacteria and enable copper ions to eradicate bacteria at lower concentrations. This dual action leads to the creation of an optimal healing environment conducive to wound healing. During the inflammatory phase, BA and Hsp could collaborate to combat inflammation, which transited from the inflammatory stage to the proliferative phase soon. Continuous release of BA and Cu2+, coupled with thermotherapy, significantly enhances epithelial and blood vessel regeneration, thereby expediting the healing of chronic wounds. Overall, this multifunctional composite hydrogel holds great promise for promoting the regeneration of infected wound tissue, making it a potential candidate for chronic wound dressings.

Engineering tools for stimulating wound healing

Wound healing is the complex physiological process of restoring the skin's integrity, structure, and function after damage caused by external conditions. The wound healing cascade may be altered due to the progression of certain diseases, such as diabetes, venous hypertension, or peripheral arterial disease, resulting in non-healing chronic wounds. Chronic wounds can be characterized by a wide variety of pathologies including increased reactive oxygen species, ineffective neutrophil activity, overabundance of pro-inflammatory cytokines, and chronic hypoxia. Medical intervention is crucial to heal chronic wounds. This review explores current research to engineer improved chronic wound treatment devices, dressings, and constructs to facilitate tissue regeneration and wound closure. This review first covers different physical stimulation therapies, then, local therapeutic delivery systems, and finally three-dimensional (bio)printing techniques for the fabrication of skin grafts and wound dressings. Additionally, the review discusses the regulatory process for bringing cutting-edge wound healing technologies to market and highlights currently approved products for wound treatment. At the end, the unmet need and future directions that the field should expand are discussed.

A Viscous-Biofluid Self-Pumping Organohydrogel Dressing to Accelerate Diabetic Wound Healing.

Viscous biofluids on wounds challenge conventional "water-absorbing" wound dressings in efficient drainage due to their poor fluidity, generally causing prolonged inflammation, anti-angiogenesis, and delayed wound closure. Herein, it is reported that a self-pumping organohydrogel dressing (SPD) with aligned hydrated hydrogel channels, prepared by a three-dimensional-templated wetting-enabled-transfer (3D-WET) polymerization process, can efficiently drain viscous fluids and accelerate diabetic wound healing. The asymmetric wettability of the hydrophobic-hydrophilic layers and aligned hydrated hydrogel channels enable unidirectional and efficient drainage of viscous fluids away from the wounds, preventing their overhydration and inflammatory stimulation. The organogel layer can adhere onto the skin around the wounds but can be easily detached from the wet wound area, avoiding secondary trauma to the newly formed tissues. Taking a diabetic rat model as an example, the SPD can significantly downregulate the inflammation response by ≈70.8%, enhance the dermal remodeling by ≈14.3%, and shorten wound closure time by about 1/3 compared with the commercial dressing (3M, Tegaderm hydrocolloid thin dressing). This study sheds light on the development of the next generation of functional dressings for chronic wounds involving viscous biofluids.

An Electrostatic‐Induction‐Enabled Anti‐Touching Hydrogel Dressing for Chronic Wound Care

AbstractChronic wounds are inherently vulnerable to external mechanical contact owing to their impaired physiological states. Accidental touching may lead to secondary damage to delicate wound tissues, including deterioration of tissue and inflammation, thereby prolonging the healing process. In addition, patients encounter nociceptive sensations, indicative of physical discomfort and potential distress. However, the traditional dressings for chronic wounds fail to convey adequate perceptual information to prevent mechanical trauma. An electrostatic‐induction‐enabled anti‐touching hydrogel dressing (EAHD) is proposed, which promotes wound healing and reduces touching‐induced injuries. The EAHD combines a proximity sensor and a pro‐healing hydrogel. The proximity sensor can detect approaching objects, enabling remote perception. More importantly, EAHD and a wireless alarm system are integrated to warn against the detected potential hazards such as unintentional touching. Meanwhile, the EAHD significantly accelerates wound healing in preclinical diabetic mice, ≈38% faster than that of the control group. This study proposes a novel strategy for multifunctional wound dressing that promotes wound healing and prevents accidental touching‐induced secondary damage to the wound.

Sodium alginate/polyvinyl alcohol nanofibers loaded with Shikonin for diabetic wound healing: In vivo and in vitro evaluation

Diabetic wounds are typically chronic wounds and the healing process is limited by problems such as high blood glucose levels, bacterial infections, and other issues that make wound healing difficult. Designing drug-loaded wound dressings is an effective way to promote diabetic wound healing. In this study, we developed an SA/PVA nanofiber (SPS) containing Shikonin (SK) for the treatment of diabetic wounds. The prepared nanofibers were uniform in diameter, had good hydrophilicity and high water vapor permeability, and effectively promoted gas exchange between the wound site and the outside world. The results of in vitro experiments showed that SPS was effective in antimicrobial, antioxidant, and biocompatible. In vivo tests showed that the wound healing rate of mice treated with SPS reached 85.5 %. Immunohistochemical staining results showed that SPS was involved in the diabetic wound healing process through the up-regulation of growth factors (CD31, HIF-1α) and the down-regulation of inflammatory factors (CD68). Western blotting experiments showed that SPS attenuated the inflammation through the inhibition of the IκBα/NF-κB signaling pathway. These results suggest that SPS is a promising candidate for future clinical application of chronic wound dressings.

DESCRIPTION OF THE USE OF CHRONIC WOUND DRESSINGS BASED ON WOUND CHARACTERISTICS

Currently, wound dressings consist of many types and have different functions. However, the many types of dressings available make it challenging to select the dressing used for wounds (Mustamu et al., 2020). This study aims to determine the description of the use of chronic wound dressings based on wound characteristics. This research design uses a quantitative research design with a retrospective approach. The instrument used in this research was the DMIST observation sheet. The primary dressing used most often at the beginning of wound care is wound half: The first primary dressing in 19 cases (26.0%) and the second primary dressing in 44 cases (60.3%).
 Meanwhile, the secondary dressing most often used at the beginning of the visit was gauze, as the first secondary dressing in 27 cases (37.0%) and the second secondary dressing in 42 cases (57.5%). Meanwhile, at the end of the treatment process, the first primary dressing was dominated by half of the wounds in 30 cases (41.1%) and the second primary dressing in 28 cases (38.4%). Meanwhile, the most frequently used secondary dressing was gauze in 18 cases (24.7%). In conclusion, the primary dressing widely used in wound care is wound zalf. The secondary dressing is dominated by gauze.
 
 Keywords: Wound Dressing, Wound Care, Wound Characteristics, Chronic Wound

Recent Applications and Evaluation of Metal Nanoparticle–Polymer Hybrids as Chronic Wound Dressings

Chronic wounds, which include venous leg ulcers, diabetic foot ulcers, and pressure ulcers, are a global health issue that affects between 1% and 2% of the developed world’s population. Chronic wound healing necessitates extensive medical intervention at costly healthcare expenses. Wound care management is mainly dependent on the discovery of new and appropriate chronic wound dressing materials, and it remains a focus of research in chronic wound care. Biocompatible metallic nanoparticle-loaded wound dressing offers a novel opportunity for effectively overcoming the inherent drawbacks of traditional wound dressing materials, particularly in overcoming nonhealing chronic wounds due to their clinical complexity, for example, wound infections, chronic irritation, and trauma, persistence of foreign body or bacterial proteins, and ischemia. In this review, we will primarily focus on the advancements in nanoparticle-based antibacterial and antioxidant wound dressing materials (e.g., hydrogels, electrospun scaffolds, sponges, and films) for the treatment of chronic wounds, which overcome the limitations of traditional dressings.

In Situ Hydrogel Formulation for Advanced Wound Dressing: Influence of Co-Solvents and Functional Excipient on Tailored Alginate-Pectin-Chitosan Blend Gelation Kinetics, Adhesiveness, and Performance.

Chronic skin wounds affect more than 40 million patients worldwide, representing a huge problem for healthcare systems. This study elucidates the optimization of an in situ gelling polymer blend powder for biomedical applications through the use of co-solvents and functional excipients, underlining the possibility of tailoring microparticulate powder properties to generate, in situ, hydrogels with advanced properties that are able to improve wound management and patient well-being. The blend was composed of alginate, pectin, and chitosan (APC). Various co-solvents (ethanol, isopropanol, and acetone), and salt excipients (sodium bicarbonate and ammonium carbonate) were used to modulate the gelation kinetics, rheology, adhesiveness, and water vapor transmission rate of the gels. The use of co-solvents significantly influenced particle size (mean diameter ranging from 2.91 to 5.05 µm), depending on the solvent removal rate. Hydrogels obtained using ethanol were able to absorb over 15 times their weight in simulated wound fluid within just 5 min, whereas when sodium bicarbonate was used, complete gelation was achieved in less than 30 s. Such improvement was related to the internal microporous network typical of the particle matrix obtained with the use of co-solvents, whereas sodium bicarbonate was able to promote the formation of allowed particles. Specific formulations demonstrated an optimal water vapor transmission rate, enhanced viscoelastic properties, gel stiffness, and adhesiveness (7.7 to 9.9 kPa), facilitating an atraumatic removal post-use with minimized risk of unintended removal. Microscopic analysis unveiled that porous inner structures were influencing fluid uptake, gel formation, and transpiration. In summary, this study provided valuable insights for optimizing tailored APC hydrogels as advanced wound dressings for chronic wounds, including vascular ulcers, pressure ulcers, and partial and full-thickness wounds, characterized by a high production of exudate.

Multifunctional hydrogels for chronic wounds repairing

AbstractBecause of their tissue‐like mechanical performances, high biocompatibility, and adjustable functionality, hydrogels have become increasingly attractive materials for promoting wound healing. Chronic wounds include burn, diabetic, and infected wounds. Unlike common incision wounds, chronic wounds are more challenging to heal. To meet the clinical needs, multifunctional hydrogels should be fabricated and investigated. To guide future studies on the fabrication of hydrogel‐based chronic wound dressings, a review of advanced multifunctional hydrogels is necessary. Various hydrogels with advanced properties, such as antibacterial, antioxidant, bioadhesive, anti‐inflammatory, and wound healing properties, that can be used for skin burn wounds and diabetic wounds are summarised. Lastly, the prospects of advanced hydrogels for wound healing are elaborated.

“Sandwich-like” structure electrostatic spun micro/nanofiber polylactic acid-polyvinyl alcohol-polylactic acid film dressing with metformin hydrochloride and puerarin for enhanced diabetic wound healing

A diabetic wound is a typical chronic wound with a long repair process and poor healing effects. It is an effective way to promote diabetic wound healing to design electrospinning nanofiber films with drug-assisted therapy, good air permeability and, a multilayer functional structure. In this paper, a diabetic wound dressing with a “sandwich-like” structure was designed. Metformin hydrochloride, loaded in the hydrophilic PVA inner layer, could effectively promote diabetic wound healing. The drug release was slowed down by osmosis. The laminate film dressing had good mechanical properties, with tensile strength and elongation at break reaching 5.91 MPa and 90.47 %, respectively, which was close to human skin. The laminate film loaded with erythromycin and puerarin in the hydrophobic PLA outer layer had good antibacterial properties. In addition, due to the high specific surface of the electrostatic spun film, it exhibited high water vapor permeability. It facilitates the gas exchange between the wound and the outside world. The cell experiments proved that the laminate film dressing had good biocompatibility. There was no toxic side effect on cell proliferation. In the diabetic animal wound model, it was shown that the closure rate of diabetic wound repair by laminate film reached 91.11 % in the second week. Our results suggest that the “sandwich-like” nanofiber film dressing could effectively promote the healing process and meet the various requirements of diabetic wound dressing as a promising candidate for future clinical application of chronic wound dressings.

A Sensor for Monitoring the Antimicrobial Activity of Wound Dressings for Both Surgical Site Infections (SSIs) and Chronic Wounds.

Antimicrobial impregnated wound dressings are a critical tool for the management, prevention, and control of surgical site infections (SSIs) and infected chronic wounds. However, the sustained therapeutic antimicrobial activity of the dressing when employed for extended periods cannot be readily determined in vivo. Consequently, dressings are changed frequently to ensure that their antimicrobial activity is maintained. Whilst frequent dressing changes allow the wound to be assessed, this is time-consuming and can cause disruption to the wound bed impairing the healing process. Furthermore, this increases medical costs for the patient and hospitals. This paper introduces a novel concept to monitor the therapeutic levels of an antimicrobial component within a wound dressing ensuring the wound dressing remains "fit for purpose" and avoiding indiscriminate use of antiseptics. This could help to inform clinicians whether the antimicrobial is still being delivered at therapeutic levels and as such when to change the dressing ensuring timely positive clinical outcomes. Silver has been used historically as an antimicrobial agent and is ubiquitous in current generations of antimicrobial wound dressings. However, its activity is complex due to the poor solubility of silver ions in the presence of chloride and the effect of complexation by other components in the dressing and wound ecosystem, not least by serum proteins. In this paper, we detail an electrochemical silver sensor (5D patent protected - WO2023275553A1), constructed using a platinum (Pt) nanoband array electrode, and characterise its response to silver ions. This is determined in the presence of bovine serum albumin (BSA) and simulated wound fluid (SWF) containing chloride and rationalised using atomic analysis of the composition of the SWF. The sensor response in SWF is compared with the antimicrobial activity of silver against Pseudomonas aeruginosa in the planktonic and biofilm state, as a function of the amount of silver nitrate added. At low concentrations, silver in SWF has good solubility but reduced antimicrobial effect due to binding of silver by BSA as shown by the sensor response. At intermediate concentrations, above 10ppm, the silver was efficacious on both planktonic microorganisms and biofilm impregnated with microorganisms and readily detected with the sensor. At high concentrations, silver precipitates and both the silver in solution and the sensor response plateaus. The data demonstrates how the sensor correlates with the antimicrobial activity of the silver in vitro and how this could be used to actively monitor antimicrobials in vivo.

Flexible Curcumin-Loaded Zn-MOF Hydrogel for Long-Term Drug Release and Antibacterial Activities.

Management of chronic inflammation and wounds has always been a key issue in the pharmaceutical and healthcare sectors. Curcumin (CCM) is an active ingredient extracted from turmeric rhizomes with antioxidant, anti-inflammatory, and antibacterial activities, thus showing significant effectiveness toward wound healing. However, its shortcomings, such as poor water solubility, poor chemical stability, and fast metabolic rate, limit its bioavailability and long-term use. In this context, hydrogels appear to be a versatile matrix for carrying and stabilizing drugs due to their biomimetic structure, soft porous microarchitecture, and favorable biomechanical properties. The drug loading/releasing efficiencies can also be controlled via using highly crystalline and porous metal-organic frameworks (MOFs). Herein, a flexible hydrogel composed of a sodium alginate (SA) matrix and CCM-loaded MOFs was constructed for long-term drug release and antibacterial activity. The morphology and physicochemical properties of composite hydrogels were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, and mechanical property tests. The results showed that the composite hydrogel was highly twistable and bendable to comply with human skin mechanically. The as-prepared hydrogel could capture efficient CCM for slow drug release and effectively kill bacteria. Therefore, such composite hydrogel is expected to provide a new management system for chronic wound dressings.

Maintenance of chronicity signatures in fibroblasts isolated from recessive dystrophic epidermolysis bullosa chronic wound dressings under culture conditions

BackgroundRecessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients.ResultsIn order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-β1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1β and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies.ConclusionsOur results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients’ chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.

811 Fibroblasts isolated from chronic wound dressings differentiate chronicity in recessive dystrophic epidermolysis bullosa

811 Fibroblasts isolated from chronic wound dressings differentiate chronicity in recessive dystrophic epidermolysis bullosa

Edaravone-Loaded Sodium Alginate/Carboxymethyl Chitosan Composite Flim for the Healing of Chronic Wound

High levels of reactive oxygen species (ROS) in the wound surface are one of the reasons why chronic wounds are difficult to heal. Using of free radical scavengers to reduce ROS levels and reduce the duration of toxic effects of ROS can accelerate the healing of chronic wounds. In this study, a novel edaravone (Ed)-loaded sodium alginate (SA)/carboxymethyl chitosan (CMCS) antioxidant composite film was prepared, and the physicochemical properties and biocompatibility were analyzed. The results indicated that the SA/CMCS/Ed films were hydrophilic, with excellent water absorption and water retention, and also exhibited adequate mechanical properties. The exploratory drug release investigation revealed that the increase in SA content plays a critical role in the Ed release process by improving the binding ability of the composite film to the drug, resulting in slow release. In addition, cell experiments confirmed that the SA/CMCS films with Ed content of 20% and 30% not only had no cytotoxicity, but also significantly promoted the cell viability of fibroblasts from oxidative stress injury induced by hydrogen peroxide. These preliminary results suggested that the Ed-loaded SA/CMCS composite film can be further used for the study of chronic wound dressings, which is expected to provide new ways for the treatment of diabetic foot ulcers, lower extremity venous ulcers and arterial ulcers.

Cobalt containing glass fibres and their synergistic effect on the HIF-1 pathway for wound healing applications.

Introduction and Methods: Chronic wounds are a major healthcare problem, but their healing may be improved by developing biomaterials which can stimulate angiogenesis, e.g. by activating the Hypoxia Inducible Factor (HIF) pathway. Here, novel glass fibres were produced by laser spinning. The hypothesis was that silicate glass fibres that deliver cobalt ions will activate the HIF pathway and promote the expression of angiogenic genes. The glass composition was designed to biodegrade and release ions, but not form a hydroxyapatite layer in body fluid. Results and Discussion: Dissolution studies demonstrated that hydroxyapatite did not form. When keratinocyte cells were exposed to conditioned media from the cobalt-containing glass fibres, significantly higher amounts of HIF-1α and Vascular Endothelial Growth Factor (VEGF) were measured compared to when the cells were exposed to media with equivalent amounts of cobalt chloride. This was attributed to a synergistic effect of the combination of cobalt and other therapeutic ions released from the glass. The effect was also much greater than the sum of HIF-1α and VEGF expression when the cells were cultured with cobalt ions and with dissolution products from the Co-free glass, and was proven to not be due to a rise in pH. The ability of the glass fibres to activate the HIF-1 pathway and promote VEGF expression shows the potential for their use in chronic wound dressings.