Mechanical and contact characteristics of foam materials within wound dressings: Theoretical and practical considerations in treatment

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

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

Foam-based antibacterial hydrogel composed of carboxymethyl cellulose/polyvinyl alcohol/cerium oxide nanoparticles for potential wound dressing

Foam-based wound dressing materials produced by dispersing gas phases in a polymeric material are soft, adapt to the body shape, and allow the absorption of wound exudate due to their porous structure. Most of these formulations are based on synthetic substances such as polyurethane. However, biopolymers have entered the field as a new player thanks to their biocompatible and sustainable nature. Incorporating biopolymers in formulations is gaining interest in scientific literature, and we extend this approach by adding antibacterial cerium oxide nanoparticles to biopolymer formulation. We introduce a novel biopolymer composite of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and cerium oxide nanoparticles (CeO2 NPs), namely PVA-CMC@CeO2. This mixture was first foamed and then cross-linked with sodium tetraborate solution, followed by a freeze-thaw process. After the novel material's spectroscopic, structural, and morphological characterization, we investigated its swelling, drug-delivery, antibacterial, and biodegradability properties PVA-CMC@CeO2 dressing effectively inhibits Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth and delivers the antibiotic drug silver sulfadiazine for up to 6 h. The antibacterial properties, good swelling, and drug release profile of the blend material show promising potential in wound care applications.

Optimising outcomes with 'Wound Balance' and dressings containing superabsorbent polyacrylate polymers

The ever-increasing burden of hard-to-heal wounds requires emphasis placed on early intervention to help heal wounds and improve patient quality of life. A patient's healing potential can be optimised by applying the 'Wound Balance' holistic framework for wound assessment, care planning and quality of life considerations. This holistic management can be facilitated with appropriate dressings, such as dressings containing superabsorbent polyacrylate polymers (SAPs), including RespoSorb® Silicone Border (Hartmann). SAP-containing dressings can absorb exudate and bind and lock away wound inhibitors, such as proteases and micro-organisms, reversing the factors associated with hard-to-heal wounds to enable a healing environment similar to an acute wound. Three case studies demonstrate the positive benefits of using RespoSorb Silicone Border in clinical practice. The dressings proved easy to use and comfortable, with atraumatic changes and long wear times, providing a costeffective option for patients with both acute and hard-to-heal wounds.

A novel polyurethane-based silver foam dressing with superior antimicrobial action for management of infected chronic wounds

Wound healing is a complex and dynamic process supported by several cellular events. Around 13 million individuals globally suffer from chronic wounds yearly, for which dressings with excellent antimicrobial activity and cell viability (>70%, as per ISO 10993) are needed. Excessive use of silver can cause cytotoxicity and has been linked to increasing antimicrobial resistance. In this study, HDI Ag foam was synthesized using a safer hexamethylene diisocyanate-based prepolymer (HDI prepolymer) instead of commonly used diisocyanates like TDI and MDI and substantially lower Ag content than that incorporated in other Ag foams. In vitro characteristics of the HDI Ag foam were evaluated in comparison with leading clinically used foam-based dressings. All dressings underwent a detailed characterization in accordance with industrially accepted BS EN 13726 standards. The HDI Ag foam exhibited highest antimicrobial efficiency againstS. aureusandP. aeruginosa(static condition), with the lowest amount of Ag (0.2 wt%) on the wound contact surface. The extracts from HDI Ag foam showed superior cell viability (>70%), when tested on the L929 mouse fibroblast cell line. Measurements of moisture vapor transmission, fluid handling, physico-chemical and mechanical properties ensured that the HDI foam was clinically acceptable for chronic wound patients.

Using patient-reported experiences to inform the use of foam dressings for hard-to-heal wounds: perspectives from a wound care expert panel

Caring for patients with hard-to-heal (chronic) wounds requires a multifaceted approach that addresses their diverse needs, which can contribute to the complexity of care. Wound care providers must have a comprehensive understanding of the patient's comorbid conditions and psychosocial issues to provide personalised and effective treatment. Key quality indicators for effective wound care involves not only selecting appropriate local wound care products, such as foam dressings, but also addressing individual patient experiences of wound-related pain, odour, itch, excessive wound drainage, and self-care needs. The purpose of this review is to inculcate the wound care practice community, research scientists and healthcare industry with a sense of accountability in order to work collaboratively in addressing these unmet care needs.

Agarose Cryogels Loaded with Polydopamine Microspheres for Sustainable Wound Care with Enhanced Hemostatic and Antioxidant Properties

Excessive bleeding presents a grave risk to life, especially in scenarios involving deep wounds such as those inflicted by gunshots and accidental stabs. Despite advancements in wound care management, existing commercial hemostatic agents have limitations, necessitating the development of enhanced solutions. In this study, we developed cryogels using agarose and polydopamine microspheres as a hemostatic dressing to effectively manage profuse bleeding. The resulting cryogels demonstrated impressive attributes, such as high absorption capacity (>4000%), shape recovery ability, antioxidant properties, and excellent biocompatibility in mammalian cell lines. Particularly noteworthy was the rapid blood clotting observed in vitro, with the agarose/PDA cryogels achieving complete clotting within just 90 s. Subsequent validation in the rat trauma model further underscored their hemostatic efficacy, with clotting times of 40 and 53 s recorded in tail amputation and liver puncture models, respectively. The porous structure and hydrophilicity of the cryogels facilitated superior blood absorption and retention, while the amine groups of polydopamine played a pivotal role in enhancing blood clotting activity. This study represents a significant step forward in utilizing agarose/polydopamine cryogels as advanced materials for hemostatic wound dressings, promising an impactful contribution to wound therapy.

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

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

Advances in ionic liquid-based antimicrobial wound healing platforms

Wound infections, marked by the proliferation of microorganisms at surgical sites, necessitate the development of innovative wound dressings with potent bactericidal properties to curb microbial growth and prevent bacterial infiltration. This study explores the recent strides in utilizing ionic liquid-based polymers as highly promising antimicrobial agents for advanced wound healing applications. Specifically, cationic polymers containing quaternary ammonium, imidazolium, guanidinium, pyridinium, triazolium, or phosphonium groups have emerged as exceptionally effective antimicrobial compounds. Their mechanism of action involves disrupting bacterial membranes, thereby preventing the development of resistance and minimizing toxicity to mammalian cells. This comprehensive review not only elucidates the intricate dynamics of the skin's immune response and the various stages of wound healing but also delves into the synthesis methodologies of ionic liquid-based polymers. By spotlighting the practical applications of antimicrobial wound dressings, particularly those incorporating ionic liquid-based materials, this review aims to lay the groundwork for future research endeavors in this burgeoning field. Through a nuanced examination of these advancements, this article seeks to contribute to the ongoing progress in developing cutting-edge wound healing platforms that can effectively address the challenges posed by microbial infections in surgical wounds.

Current progress of protein-based dressing for wound healing applications - A review

Protein-based wound dressings have garnered increasing interest in recent years owing to their distinct physical, chemical, and biological characteristics. The intricate molecular composition of proteins gives rise to unique characteristics, such as exceptional biocompatibility, biodegradability, and responsiveness, which contribute to the promotion of wound healing. Wound healing is an intricate and ongoing process influenced by multiple causes, and it consists of four distinct phases. Various treatments have been developed to repair different types of skin wounds, thanks to advancements in medical technology and the recognition of the diverse nature of wounds. This review has literature reviewed within the last 3-5 years-the recent progress and development of protein in wound dressings and the fundamental properties of an ideal wound dressing. Herein, the recent strides in protein-based state-of-the-art wound dressing emphasize the significant challenges and summarize future perspectives for wound healing applications.

Computational Designed and Optimized Liposomal Curcumin-Embedded Bifunctional Cross-Linked Hydrogels for Wound Healing

Curcumin (CUR) bifunctional cross-linked nanocomposite hydrogels are presented as an efficient method for CUR delivery in wound healing. CUR-loaded liposomes (CUR-Ls) were optimized using the Box-Behnken design to augment particle size, size distribution, zeta potential, and CUR concentration. The antioxidant activity and cytotoxicity of CUR-Ls were assessed. Hyaluronic acid (HA)/poly(vinyl alcohol) (PVA) hydrogels were optimized with a central composite design; then, poly(N-vinylpyrrolidone-co-itaconic acid) (PNVP-ITA) was synthesized to enrich the properties of the hydrogels. The drug release kinetics of the CUR-L@HA/PVA/PNVP-ITA hydrogels were studied. Skin recovery was investigated in vivo on rat dorsal skin. The optimized CUR-Ls were constructed from 2.7% Tween® 20, 0.04% oleic acid, and 8.1% CUR, yielding nano-CUR-L with a narrow size distribution, negative surface charge, and CUR content of 19.92 ± 0.54 µg/mg. CUR-Ls improved the antioxidant effects of CUR. The optimized hydrogel contained 5% HA and 10% PVA. PNVP-ITA improved the properties of the hydrogels via enhanced cross-linking. CUR-Ls exhibited a more rapid release than CUR, whereas the hydrogels enhanced CUR release via a diffusion-controlled mechanism. CUR-L@HA/PVA/PNVP-ITA hydrogels improved the skin recovery rate compared to the commercial patch after 5 days. Therefore, the optimized CUR-L@HA/PVA/PNVP-ITA hydrogels facilitated skin recovery and could be a promising nanocomposite for wound dressings.

Performance of a silicone foam dressing in management of wounds in a community setting: a sub-analysis of the VIPES study

OBJECTIVE

Managing the gap between the dressing and the wound bed can facilitate the healing of exuding wounds. A silicone foam dressing (Biatain Silicone; Coloplast A/S, Denmark) was developed for application to exuding wounds. A sub-analysis of the real-world, prospective, observational VIPES (Observatoire en Ville des Plaies ExSudatives) study was conducted to investigate the use and performance of the silicone foam dressing in a community nursing setting in France.

METHOD

The sub-analysis included patients from the VIPES study who received the silicone foam dressing as a primary dressing for an acute or hard-to-heal (chronic) wound. Epidemiological and wound healing outcomes were reported via a smartphone application.

RESULTS

Overall, 64 patients were included in the sub-analysis. At baseline, most wounds (n=33/40; 82.5%) were in treatment failure (i.e., were stagnant, non-healing or had poor exudate management). At the last follow-up visit, a median of 22.5 (range: 3-151) days post baseline, 48.4% of wounds had healed and 25.0% were progressing towards healing. From baseline to the last follow-up visit, significant reductions in exudate level (p<0.0001) and exudate pooling (p<0.0001), and significant improvements in wound edges (p≤0.0001) and periwound skin (p<0.01) were observed. A total of 62.3% of patients had re-epithelialising wounds at the last follow-up visit. The majority of nurses (88.3%) and patients (85.0%) reported that the wound had improved and, at most dressing removals (93.5%), nurses reported that the dressing conformed closely to the wound bed.

CONCLUSION

Overall, the data suggest that use of the silicone foam dressing in community practice supported the healing of wounds, illustrating the importance of exudate and gap management.

Streamlining Skin Regeneration: A Ready-To-Use Silk Bilayer Wound Dressing

Silk proteins have been highlighted in the past decade for tissue engineering (TE) and skin regeneration due to their biocompatibility, biodegradability, and exceptional mechanical properties. While silk fibroin (SF) has high structural and mechanical stability with high potential as an external protective layer, traditionally discarded sericin (SS) has shown great potential as a natural-based hydrogel, promoting cell-cell interactions, making it an ideal material for direct wound contact. In this context, the present study proposes a new wound dressing approach by developing an SS/SF bilayer construct for full-thickness exudative wounds. The processing methodology implemented included an innovation element and the cryopreservation of the SS intrinsic secondary structure, followed by rehydration to produce a hydrogel layer, which was integrated with a salt-leached SF scaffold to produce a bilayer structure. In addition, a sterilization protocol was developed using supercritical technology (sCO2) to allow an industrial scale-up. The resulting bilayer material presented high porosity (>85%) and interconnectivity while promoting cell adhesion, proliferation, and infiltration of human dermal fibroblasts (HDFs). SS and SF exhibit distinct secondary structures, pore sizes, and swelling properties, opening new possibilities for dual-phased systems that accommodate the different needs of a wound during the healing process. The innovative SS hydrogel layer highlights the transformative potential of the proposed bilayer system for biomedical therapeutics and TE, offering insights into novel wound dressing fabrication.

Development of PU foam dressings loaded with extract of Plectranthus amboinicus for burn wound healing

OBJECTIVE

To develop Plectranthus amboinicus extract loaded Polyurethane foam dressing for burn wound healing.

SIGNIFICANCE

Plectranthus amboinicus is traditionally used as an anti-inflammatory and wound-healing agent. Its incorporation in a PU foam dressing will offer the dual benefits of foam dressing as well as the healing potential of P. amboinicus.

METHODS

PU foam dressings were prepared and loaded with P. ambionicus leaf extract (PAE). The dressings were prepared with varying concentrations (0.5-2%) of extract along with Toluene diisocyanate, polypropylene glycol (PPG), and liquid paraffin. The dressings were characterized by Scanning Electron Microscopy and evaluated for Moisture Vapor Transmission Rate, absorption rate, porosity, and mechanical strength followed by in vivo burn wound-healing studies in comparison to a marketed dressing.

RESULTS

The MVTR was found to be optimum in formulations FD2-FD4 with values ranging from 2068.06 ± 0.99 to 2095.00 ± 0.25 g/m2/day. Absorption rate was found to be between 1.27 ± 0.01, 1.31 ± 0.00, and 1.30 ± 0.02 g/cm2 for formulations FD2-FD4. Formulations FD1, FD2, FD3, FD4 showed better porosity when compared to other formulations. Formulation FD4 was further characterized by micro-CT and a porosity of 46.32% was obtained. Tensile strength measurement indicated that the selected formulations were flexible enough to withstand regular handling during dressing changes. Acute dermal irritation performed on rabbits showed no irritation, erythema, eschar, and edema. In vivo wound-healing studies performed on albino wistar rats showed that the FD4 formulation has better wound healing property.

CONCLUSION

Plectranthus ambionicus-loaded PU foam dressing demonstrated promising burn wound-healing potential.

Clinical performance characteristics for bordered foam dressings in the treatment of complex wounds: An international wound dressing technology expert panel review

The aim of this article is to identify and describe clinical practice performance characteristics for bordered foam dressings in the treatment of complex wounds. Our recently published systematic review of outcomes and applied measurement instruments for the use of bordered foam dressings in complex wounds has led to us identifying a range of important clinical and patient-centred issues related to this dressing class. Specifically, here, we focus on an overview of performance criteria in the areas of application, adhesion, exudate management and debridement functions of bordered foam dressings. Our hope is that by highlighting the clinical performance criteria, future testing standards for wound dressings will more closely match our clinical expectations and, thereby, assist clinicians to make better wound treatment choices based on meaningful and clinically relevant dressing product performance standards. complex wounds, complex wound care, treatment, bordered foam dressings, dressing performance.

A robotic venous leg ulcer system reveals the benefits of negative pressure wound therapy in effective fluid handling

We applied a market-leading, single-use negative pressure wound therapy device to a robotic venous leg ulcer system and compared its fluid handling performance with that of standard of care, superabsorbent and foam dressings and compression therapy. For each tested product, we determined a metrics of retained, residual, evaporated and (potential) leaked fluid shares, for three exudate flow regimes representing different possible clinically relevant scenarios. The single-use negative pressure wound therapy system under investigation emerged as the leading treatment option in the aspects of adequate fluid handling and consistent delivery of therapeutic-level wound-bed pressures. The superabsorbent dressing performed reasonably in fluid handling (resulting in some pooling but no leakage), however, it quickly caused excessive wound-bed pressures due to swelling, after less than a day of simulated use. The foam dressing exhibited the poorest fluid handling performance, that is, pooling in the wound-bed as well as occasional leakage, indicating potential inflammation and peri-wound skin maceration risks under real-world clinical use conditions. These laboratory findings highlight the importance of advanced robotic technology as contemporary means to simulate patient and wound behaviours and inform selection of wound care technologies and products, in ways that are impossible to achieve if relying solely on clinical trials and experience.

The development of a core outcome set for clinical effectiveness studies of bordered foam dressings in the treatment of complex wounds

AIM

The aim of this project was to develop a core outcome set (COS) for clinical effectiveness studies of bordered foam dressings in the treatment of complex wounds.

METHODS

The research project followed the Core Outcome Measures in Effectiveness Trials (COMET) initiative and consisted of two phases. The first phase prepared the background and process, while the second phase had three steps: outcome list generation via systematic review and qualitative study, Delphi consensus study, and consensus meeting. The study has been registered in the Core Outcome Measures in Effectiveness Trials database.

RESULTS

The systematic review resulted in 82 outcomes and 20 additional outcomes were obtained during the interviews. After refinement, 111 panellists from 23 countries rated a list of 51 outcomes. In the following consensus meeting, six outcomes were prioritized to be included in the core outcome set. After the consensus meeting, a patient-reported outcome was added to the core outcome set.

CONCLUSION

The COS for evaluating the effectiveness of bordered foam dressings in treating complex wounds includes 7 outcomes: "ability to stay in place", "leakage", "pain", "dressing related periwound skin changes", "change in wound size over time", and "overall satisfaction". These identified outcomes are correlated with contemporary bioengineering testing and evaluation methods for dressing performance, which underpins the need for a close multidisciplinary collaboration to advance the field of wound dressings. The outcome 'overall satisfaction' reflects the impact of complex wounds and their treatment on a patient's daily life. The use of these outcomes is recommended to improve data synthesis and promote evidence-based practice. Future developments in COS development involve creating measurement instruments and relevant endpoints for these outcomes.