Burn injury: Challenges and advances in burn wound healing, infection, pain and scarring

A carboxymethyl chitosan and dextran hydrogel with slow and rapid photothermal conversion for sequential promoting burn wound healing and inhibiting scar proliferation

Facilitating swift burn wound healing while effectively preventing scar formation continues to be a considerable challenge in medical practice. In this study, an injectable carboxymethyl chitosan/oxidized dextran/polyvinylpyrrolidone/dopamine (COPD) hydrogel was designed for the effective sequentially promotion of burn wound healing and inhibition of scar formation. The COPD hydrogel precursor solution was injected into the burn wound via a double-barreled syringe and transformed into an adherent hydrogel within 25 s. The inclusion of dopamine imparted good free radical scavenging properties to the hydrogel. In particular, the gradual oxidation of dopamine to polydopamine enabled a unique heat production pattern-initially slow (photothermal conversion efficiency: 30.3 %) and then rapidly temperature increasing (photothermal conversion efficiency: 42.8 %) -under single laser irradiation. The effect of promoting healing at the initial stage of the wound was evaluated by constructing a male C57BL/6 mice model with deep second-degree burns, observation of the wound area, PCR analysis, and immunohistochemical staining. Furthermore, the scar inhibition was confirmed by observing reduced expression levels of α-SMA and COLI, along with a decreased collagen I/III ratio. With tunable mechanical properties (maximum compressive strength of 966.4 ± 51.7 kPa), the COPD hydrogel holds significant promise as an adjunctive photothermal platform for intelligent burn wound management.

G(1-5)-EM2, a multi-targeted agonist to opioid and growth hormone secretagogue receptors exhibited nontolerance forming antinociceptive effects in a mouse model of burn pain

Burn induced-pain (BIP) is one of the most common pain symptoms, which seriously affects the quality of sufferer life. Researches show that multi-targeted drug therapies offer superior efficacy and fewer side effects compared to single-target drug therapies. Consequently, in this study, we developed G(1-5)-EM2, a multi-targeted peptide designed to target μ-opioid receptor and the growth hormone secretagogue receptor 1α (GHS-R1α), and explored its antinociceptive effects on burn injury pain. Calcium mobilization experiments revealed that G(1-5)-EM2 demonstrated weak multi-agonist activities to μ-opioid receptor and κ-opioid receptor as well as GHS-R1α in vitro. Near-infrared fluorescence imaging experiments demonstrated that G(1-5)-EM2 could penetrate the blood-brain barrier (BBB) and access the brain following intravenous injection. The enzymatic stability of G(1-5)-EM2 was significantly enhanced compared to EM2. Our results indicated that intrathecal administration of G(1-5)-EM2 mitigated mechanical allodynia and thermal hyperalgesia in BIP. These antinociceptive effects of G(1-5)-EM2 were partially mediated through μ-opioid receptor and GHS-R1α. Moreover, intrathecal administration of G(1-5)-EM2 significantly decreased burn-induced up-regulation of phosphorylated p38 MAPK, phosphorylated NF-κBp65 and TRPV1 in the ipsilateral spinal cord, reduced the levels of IL-1β, IL-6 and TNF-α in serum, and enhanced wound healing in burned skin. Repeated intrathecal administration of G(1-5)-EM2 produced a non-tolerance-forming antinociception in BIP. These results suggest that the multi-targeted peptide G(1-5)-EM2 exhibits a novel role in alleviating BIP with fewer side effects and may represent a promising strategy for developing new analgesic drugs.

Indications for the use of dermal substitutes in patients with acute burns and in reconstructive surgery after burns: A systematic review

Deep dermal and full-thickness burns often result in scar sequelae such as contractures, hypertrophy, pain and itching following split-thickness skin grafting. Dermal substitutes are currently employed alongside split-thickness skin grafting to enhance clinical outcomes, though their indications remain a subject of ongoing debate. This systematic review aims to clarify the indications for the application of dermal substitutes in burn patients, in both acute and reconstructive settings. A comprehensive search across various databases was conducted. Studies (n = 190) assessing the indications and outcomes of dermal substitutes in acute burn patients and those requiring reconstructive surgery were included. Data extraction included the applied dermal substitute, age, total body surface area, wound depth, burn aetiology, anatomical site and exclusion criteria. The indications were derived from predetermined indications, i.e. inclusion and exclusion criteria and patient characteristics. The depth of the wound emerged as the primary indication for dermal substitute use. A one-stage approach is recommended for deep dermal to full-thickness wounds larger than 10 cm2, while a two-stage approach is advised for wounds of this depth with limited donor sites or exposed bone or tendon. No definitive age or burn/scar location thresholds were identified, and careful consideration is advised for electrical and chemical burns. Contraindications include wound infections and allergies to matrix components. Limited data exist on use in patients with diabetes mellitus, chronic vascular disease, or immunocompromised status. This is the first review to address the indications for dermal substitutes in burn patients, providing valuable insights for the development of international evidence-based treatment guidelines.

Isotonic medium treatment limits burn wound microbial colonisation and improves tissue repair

Burn injuries undergo a complex healing process in which progressive spreading of epithelial damage can lead to secondary complications such as wound infection, which is a major driver of mortality among burn patients. We recently reported that burning larval zebrafish triggers dysregulated keratinocyte dynamics compared to mechanical injury. Here, we investigate keratinocyte behaviour following burn injury and the subsequent potential for microbial colonisation of burn wounds over time. Real-time imaging, coupled with tracking of photoconverted cells, revealed that early keratinocyte motility contributes to the spread of epithelial damage beyond the initial site of burn injury and that increased epithelial damage was associated with wound colonisation by the fungal pathogen Candida albicans. Modulating osmotic balance by treating larval zebrafish with isotonic medium limited the spread of epithelial damage and reduced microbial colonisation of burn wounds. Using cultured human skin, we found that topical treatment with isotonic solution (saline) similarly prevented the spread of epithelial damage over time. These findings indicate that keratinocyte behaviour contributes to burn wound progression in larval zebrafish and links keratinocyte dynamics to microbial colonisation of burn wounded tissue.

Nanoenzymes-Integrated and Microenvironment Self-Adaptive Hydrogel for the Healing of Burn Injury and Post-Burn Depression

Burn injuries often cause prolonged oxidative stress and inflammatory pain due to an initial increase in inflammatory responses, consequently exacerbating depressive disorders and severely impairing patients' quality of life. The primary function of traditional burn dressings is to prevent infection and facilitate tissue repair. However, these dressings are not intended for the inflammatory pain and depression that often occur during recovery. This study describes a self-healing hydrogel H@EFCP, which is designed to alleviate inflammatory pain and post-burn depression in burn injuries. This hydrogel is synthesized through the cross-linking of carboxymethyl chitosan with borate ester chelates formed from epigallocatechin gallate and 4-formylphenylboronic acid. The incorporated Prussian blue nanoparticles increase the ability of H@EFCP to regulate the inflammatory process. H@EFCP is effective in the treatment of skin burns by reducing oxidative stress and improving the microenvironment of peripheral inflammation in mice. This modulation consists of a reduction of central nervous system inflammation and the risk of post-burn depression. Behavioral assays indicate that the hydrogel significantly reduces feelings of despair and anxiety after burns. Consequently, H@EFCP provides a dual-effect solution for the care and recovery of burn patients, including both burn repair and the associated psychological effects.

A Novel Crosslinking Approach for Biomanufacturing of a Collagen-Based Skin Dermal Template

Third-degree burns result in extensive damage to the skin's epidermal and dermal layers, with limited treatment options available. Currently, xenogeneic collagen-based skin grafts are used as scaffolds to integrate into the wound bed and provide a template for neodermis formation. Existing commercial products like Integra dermal templates rely on a time-consuming and variable dehydrothermal (DHT) crosslinking process. This study presents a novel crosslinking process for collagen sponges, utilizing UV irradiation followed by glutaraldehyde (GA) crosslinking. This UV method allows to fine-tune the template's crosslink density and degradation profile while significantly reducing the total crosslinking time from 48 to 24 h compared to DHT/GA crosslinking. In vitro characterization and in vivo validation are conducted using a full-thickness skin wound mouse model. The collagen template supports the human dermal fibroblast cell line WS-1 proliferation more effectively than the Integra template after 2 weeks in culture. Additionally, in vivo data indicate a similar level of regeneration of full-thickness skin wounds in mouse models between the sponge and Integra templates. Furthermore, the sponge template does not elicit any abnormal angiogenic or immune responses. The crosslinking approach offers a promising alternative production process for collagen sponge scaffolds.

Clinical Symptoms of Postburn Hypertrophic Scars and Analysis of Risk Factors for Itching and Pain Requiring Pharmacological Intervention

BACKGROUND

Pruritus and pain symptoms secondary to hypertrophic scars (HTSs) are associated with multiple factors, with age, body mass index (BMI), and scar thickness being the main risk factors (RFs).

OBJECTIVE

This study mainly discusses the clinical symptoms associated with postburn HTSs and analyzes RFs for itching and pain requiring pharmacological intervention.

MATERIALS AND METHODS

All clinical data of 93 patients with postburn HTSs who visited the Burn Department of Shanghai Seventh People's Hospital between January 1, 2021 and January 1, 2023 were collected and analyzed retrospectively. Referring to the University of North Carolina "4P" Scar Scale, patients were rated as either "with" or "without" according to whether they had "scar itching symptoms requiring pharmacological intervention."

RESULTS

Smoking, third-degree burns, unused silicone drugs, and total burn surface area 30% to 50% were independent RFs for requiring pharmacological intervention for postburn scar pruritus (odds ratio [OR] = 2.998, 3.924, 3.588, and 5.965, p < .05). Age, increased BMI, greater scar thickness, and duration of hyperplasia not more than 1 year significantly increased the risk of scar pain requiring medical intervention (OR = 1.626, 2.441, 20.830, 11.646, and 11.136, p < .05).

CONCLUSION

The clinical value of these factors is that they can help physicians better identify those patients who may require pharmacological intervention to control itching and pain.

NIR-responsive injectable nanocomposite hydrogels with enhanced angiogenesis for promoting full-thickness wound healing

Angiogenesis plays a vital role in the treatment of full-thickness wounds. Deferoxamine (DFO) has been employed to promote neovascularization, however, smart drug delivery systems are needed to optimize its utilization. In this study, an injectable extracellular matrix (ECM)-mimicking hydrogel (HOG@P&D) was developed by leveraging the dynamic Schiff base and hydrogen bonds among a chitosan derivative (HACC), oxidized alginate (OSA), gelatin, and DFO-loaded polydopamine nanoparticles (P&D) for efficient wound healing. The incorporation of P&D enables HOG@P&D to respond to near-infrared (NIR) irradiation, converting laser energy into heat to trigger an on-demand, rapid release of DFO, thereby effectively enhancing angiogenesis. In vitro tube formation assays revealed that the number of meshes in the HOG@P&D group was fourfold higher than that of the control group. Additionally, HOG@P&D exhibited superior mechanical properties, tissue adhesion, and injectability, allowing it to cover wounds seamlessly. This hydrogel also demonstrated antibacterial and antioxidant properties, creating a conducive microenvironment for wound healing. In vivo studies further confirmed that HOG@P&D promoted angiogenesis and mitigated inflammation by upregulating angiogenic growth factor expression, thereby accelerating full-thickness wound healing. This nanocomposite hydrogel shows significant potential as a high-performance wound dressing.

Dynamic silicone hydrogel gauze coatings with dual anti-blood adhesion mechanism for rapid hemostasis and minimal secondary damage

Hemostatic materials that can rapidly control bleeding without causing secondary damage or sharp pain upon removal are receiving increasing demands in acute trauma treatments and first-aid supplies. Here, we report the development of a dynamic silicone hydrogel coating on medical gauze to enable rapid hemostasis and synergistic anti-blood adhesion properties. The silicone hydrogel can spontaneously form oriented cross-linked structures on fibrous medical gauze through a solution-processing method to achieve macroscopic superhydrophobicity with microscopic surface slipperiness, resulting in excellent anti-blood adhesion with the on-wound peeling force at ~0 millinewton. The development of dynamic silicone hydrogel coating on medical gauze enables a unique integration of advanced features including instant bleeding control, excellent anti-blood adhesion, and excellent air permeability. The proposed strategy is also suitable for scalable production, making it promising in the applications of trauma management.

Exploring the potential mechanisms of the ethyl acetate fraction of Hippophae rhamnoides L. seeds as a natural healing agent for wound repair

ETHNOPHARMACOLOGICAL RELEVANCE

Sea buckthorn (Hippophae rhamnoides L.) has been designated a "medicine food homology" fruit by the National Health Commission of China due to its nutritional value. In traditional Chinese ethnomedicine, Hippophae rhamnoides L. is commonly used to treat nonhealing wounds such as burns, sores, and gastric ulcers. The aim of this study was to explore the healing effects of the ethyl acetate extract of sea buckthorn seeds (SBS-EF) on burn wounds.

AIM OF THE STUDY

The primary objectives of this research were to determine the most effective medicinal site of action for treating burns with sea buckthorn seeds (SBS) and to investigate the underlying material basis and mechanisms of their therapeutic effects.

MATERIALS AND METHODS

The effects of different components of SBS-EF on the proliferation and migration of human skin fibroblasts (HSFs) were evaluated via MTT assays, scratch assays, transwell assays, and hydroxyproline secretion analysis. SBS-EF displayed the greatest activity amongst the extracts. Subsequent analyses included network pharmacology methodology, molecular docking studies, ultraperformance liquid chromatography UPLC-Orbitrap-Exploris-120-MS and a severe second-degree burn rat model to investigate the chemical constituents and potential therapeutic mechanisms of the SBS-EF.

RESULTS

In vitro studies demonstrated the efficacy of SBS-EF in promoting HSF growth and migration. UPLC-Orbitrap-Exploris-120-MS analysis revealed that SBS-EF had ten major constituents, with flavonoids being the predominant compounds, especially catechin, quercetin, and kaempferol derivatives. Network pharmacology and molecular docking analyses indicated that SBS-EF may exert its healing effects by modulating the Wnt/β-catenin signalling pathway. Subsequent in vivo experiments demonstrated that SBS-EF accelerated burn wound healing in rats, increased hydroxyproline expression in skin tissue, facilitated skin structure repair, and enhanced collagen production and organisation over a 21 d period. Additionally, exposure to SBS-EF upregulated WNT3a and β-catenin while downregulating GSK-3β levels in rat skin tissue.

CONCLUSIONS

The wound healing properties of SBS-EF were attributed to its ability to enhance HSF growth and migration, increase hydroxyproline levels in the skin, promote collagen accumulation, reduce scarring, and decrease the skin water content. SBS-EF may also provide therapeutic benefits for burns by modulating the Wnt/β-catenin signalling pathway, as evidenced by its effective site and likely mechanism of action in the treatment of burned rats.

Pain management with virtual reality in burn patients: a literature review

Burns are injuries to the skin or the underlying tissue system caused by heat, radiation, electricity, friction or chemicals. Burns can cause pain and discomfort during dressing changes; a person's pain response varies depending on individual perception. The pain response can indicate tissue damage in the body, as pain causes a person to experience discomfort. Pain can be interpreted as a subjective sensory response and an unpleasant emotional experience associated with actual or potential tissue damage. Pain is usually managed with pharmacological and non-pharmacological therapy. An example of non-pharmacological therapy is the use of distraction techniques, such as virtual reality (VR). VR diverts pain by creating a 3D environment with a screen and VR glasses. It allows the patient to immerse themselves in a virtual world complete with sound and music. The volume can be adjusted as needed and the patient can interact with the virtual world. The purpose of this study is to determine the characteristics and effectiveness of VR pain management in burn patients. The method used in this study is a literature review using the Preferred Reporting Items For Systematic Review (PRISMA). The authors searched for journal articles using the Science Direct, PubMed, and Google Scholar databases, covering the period from 2015-2023. The keywords used were pain management, virtual reality and burn injury. Based on the predetermined inclusion criteria, 10 articles were selected for the review. The results of this study, based on the analysis of 10 articles, indicated that the distraction or transition method (non-pharmacological management using VR) was effective in reducing pain and discomfort during dressing changes in patients with mild to moderate burns, across various age groups from infants and children to adults. Clinicians can leverage VR technology to tailor interventions based on individual patient needs, across all age groups, enhancing patient comfort and engagement during procedures.

Patient-reported scar quality in paediatric and adult burn patients: A long-term multicentre follow-up study

BACKGROUND

Burn scar maturation can take several years but is generally studied shortly after injury. Therefore, we investigated patient-reported scar quality up to 5-7 years post-burn.

METHODS

Patients with ≤ 20 % total body surface area burned completed the Patient Scale of the Patient and Observer Scar Assessment Scale (POSAS 2.0) on the same scar at 3, > 18 months (median 28 months) and 5-7 years (median 63 months) post-burn.

RESULTS

Fifty-eight patients (21 children; 37 adults) with a median total body surface area burned (TBSA) of 6.3 % participated. Average patient-reported scar quality (POSAS score) was generally worst at 3 months (median score: 4.2), best at 28 months (median score: 2.2) and intermediate at 63 months post-burn (median score: 3.4) (p < 0.001). Many patients (66 %) reported a median 1.8 point higher (worse) POSAS score at 63 months compared to 28 months post-burn, whereas 14 % reported an identical, and 21 % a lower (better) score. At any assessment, largest differences with normal skin were reported for scar colour. Univariate predictive factors of long-term patient-reported scar quality were scar quality at 3 months (p = 0.002) and 28 months post-burn (p < 0.001), full-thickness burn size (p = 0.033), length of hospital stay (p = 0.003), and number of surgeries (p < 0.001).

CONCLUSION

Two-thirds of patients with burns up to 20 % TBSA scored the quality of their scars worse at 63 months compared to 28 months post-burn. Whether this corresponds to increased dissatisfaction with scars in the long term should be further investigated. These new insights add to the body of knowledge on scar maturation and underscores the importance of discussing patients' expectations.

Multifunctional layered microneedle patches enable transdermal angiogenesis and immunomodulation for scarless healing of thermal burn injuries

Thermal burn injuries induce substantial alterations in the immune compositions and anatomical structures in the skin, which are characterized by strong inflammatory responses and thick eschar formation on the wound surface. These traits challenge current treatment paradigms due to insufficient drug penetration into affected tissues and the unsatisfactory wound regeneration. Herein, we report a layered microneedle (MN) patch for addressing these challenges in burn injury healing. The MN patch features a core/shell structure with methacrylated gelatin (GelMA) encapsulated with human umbilical vein endothelial cell (HUVECs)-derived hypoxia-induced exosomes (EXO-H) as the bottom layer and sodium alginate (SA) containing naringin (Nar)-loaded CaCO3 nanoparticles (CaCO3@Nar) as the top layer. Upon administration onto thermal burn injury site, the MN patches enable transdermal drug delivery by perforating the eschar. The spontaneous degradation of CaCO3@Nar in the interstitial fluid triggers sustained Nar release to alleviate local inflammation and scavenge excessive reactive oxygen species (ROS). Meanwhile, EXO-H significantly promote the migration and proliferation of HUVECs and enhance their angiogenesis capacity to support scarless wound tissue regeneration. The MN patch in this work successfully promoted scarless healing of skin burn injuries on rat models, providing an approach for thermal burn treatment in the clinics.

Exploring the therapeutic potential of different sources of mesenchymal stem cells: a novel approach to combat burn wound infections

The most prevalent and harmful injuries are burns, which are still a major global health problem. Burn injuries can cause issues because they boost the inflammatory and metabolic response, which can cause organ malfunction and systemic failure. On the other hand, a burn wound infection creates an environment that is conducive to the growth of bacteria and might put the patient at risk for sepsis. In addition, scarring is unavoidable, and this results in patients having functional and cosmetic issues. Wound healing is an amazing phenomenon with a complex mechanism that deals with different types of cells and biomolecules. Cell therapy using stem cells is one of the most challenging treatment methods that accelerates the healing of burn wounds. Since 2000, the use of mesenchymal stem cells (MSCs) in regenerative medicine and wound healing has increased. They can be extracted from various tissues, such as bone marrow, fat, the umbilical cord, and the amniotic membrane. According to studies, stem cell therapy for burn wounds increases angiogenesis, has anti-inflammatory properties, slows the progression of fibrosis, and has an excellent ability to differentiate and regenerate damaged tissue. Figuring out the main preclinical and clinical problems that stop people from using MSCs and then suggesting the right ways to improve therapy could help show the benefits of MSCs and move stem cell-based therapy forward. This review's objective was to assess mesenchymal stem cell therapy's contribution to the promotion of burn wound healing.

Recent advances in mesoporous silica nanoparticles formulations and drug delivery for wound healing

Wound healing is a natural process that can be disrupted by disease. Nanotechnology is a promising platform for the development of new therapeutic agents to accelerate acute and chronic wound healing. Drug delivery by means of nanoparticles as well as wound dressings have emerged as suitable options to improving the healing process. The characteristics of mesoporous silica nanoparticles (MSNs) make them efficient carriers of pharmaceutical agents alone or in combination with dressings. In order to maximize the effect of a drug and minimize its adverse consequences, it may be possible to include targeted and intelligent release of the drug into the design of MSNs. Its use to facilitate closure of adjacent sides of a cut as a tissue adhesive, local wound healing, controlled drug release and induction of blood coagulation are possible applications of MSNs. This review summarizes research on MSN applications for wound healing. It includes a general overview, wound healing phases, MSN formulation, therapeutic possibilities of MSNs and MSN-based drug delivery systems for wound healing.

Effectiveness of Autologous Skin Cell Suspension in Large Total Body Surface Area Burns: Analysis of Clinical Outcomes and Patient Charges

Autologous skin cell suspension (ASCS) is an adjunct to conventional split-thickness skin grafts (STSG) for acute burns, enhancing healing and reducing donor site requirements. This study validates ASCS's predictive benefits in hospital stay reduction and cost savings by analyzing outcomes and real-world charges post-ASCS implementation at a single institution. A retrospective study (2018-2022) included burn patients with ≥10% TBSA. The study population comprised 2 groups: burns treated either with a combination of ASCS ± STSG or with STSG alone. Outcomes included LOS, surgeries, infection, complications, days on antibiotics, and adjusted charge per TBSA. The ASCS ± STSG group demonstrated significantly shorter LOS (Mdn: 16.0 days, IQR: 10-26) than the STSG group (Mdn: 20.0 days, IQR: 14-36; P = .017), and fewer surgeries (Mdn: 1.0, IQR: 1-2) versus the STSG group (Mdn: 1.0, IQR: 1-4; P = .020). Postoperative complications were significantly lower in ASCS ± STSG (11% vs. 36%; P < .001). The STSG group had a longer distribution of antibiotic days (IQR: 0-7.0, min-max: 0-76) than the ASCS ± STSG group (IQR: 0-0, min-max: 0-37; P = .014). Wound infection incidence did not differ (P = .843). ASCS ± STSG showed a lower distribution of adjusted charge per TBSA (IQR: $10 788.5-$28 332.6) compared to the STSG group (IQR: $12 336.8-$29 507.3; P = .602) with a lower mean adjusted charge per TBSA ($20 995.0 vs. $24 882.3), although this was not statistically significant. ASCS ± STSG utilization demonstrated significant reductions in LOS, surgeries, postoperative complications, antibiotics, and potential cost savings. These findings underscore the practicality of integrating ASCS in burn management, offering substantial benefits to patients and healthcare institutions.

Sodium alginate/carboxymethylcellulose gel formulations containing Capparis sepieria plant extract for wound healing

Aim: Using appropriate wound dressings is crucial when treating burn wounds to promote accelerated healing.Materials & methods: Sodium alginate (SA)-based gels containing Carboxymethyl cellulose (CMC) and Pluronic F127 were prepared. The formulations. SA/CMC/Carbopol and SA/CMC/PluronicF127 were loaded with aqueous root extract of Capparis sepiaria. The formulations were characterized using appropriate techniques.Results: The gels' viscosity was in the range of 676.33 ± 121.76 to 20.00 ± 9.78 cP and in vitro whole blood kinetics showed their capability to induce a faster clotting rate. They also supported high cell viability of 80% with cellular migration and proliferation. Their antibacterial activity was significant against most bacteria strains used in the study.Conclusion: The gels' distinct features reveal their potential application as wound dressings for burn wounds.

Design of an Innovative Method for Measuring the Contractile Behavior of Engineered Tissues

Hypertrophic scarring is a common complication in severely burned patients who undergo autologous skin grafting. Meshed skin grafts tend to contract during wound healing, increasing the risk of pathological scarring. Although various technologies have been used to study cellular contraction, current methods for measuring contractile forces at the tissue level are limited and do not replicate the complexity of native tissues. Self-assembled skin substitutes (SASSs) were developed at the "Centre de recherche en organogénèse expérimentale de l'Université Laval/LOEX" and are used as permanent full-thickness skin grafts. The autologous skin substitutes are produced using the self-assembly method, allowing the cultured cells to produce their extracellular matrix leading to a tissue-engineered substitute resembling the native skin. The level of contraction of the SASSs during the fabrication process is patient-dependent. Thus, because of its architecture and composition, SASS is an interesting model to study skin contraction in vitro. Unfortunately, standard measurement methods are unsuited for SASS contraction assessment, mainly due to incompatibilities between the SASS manufacturing process and the current contraction force measurement methods. Here, we present an innovative contraction measurement method specifically designed to quantify the contractile behavior of tissue-engineered substitutes, without disrupting the protocol of production. The method uses C-shape anchoring frames that close at different speeds and magnitudes according to the tissue contractile behavior. A finite element analysis model is then used to associate the frame deformation to a contractile force amplitude. This article shows that the method can be used to measure the contraction force of tissues produced with cells displaying different contractile properties, such as primary skin fibroblasts and myofibroblasts. It can also be used to study the effects of cell culture conditions on tissue contraction, such as serum concentration. This protocol can be easily and affordably applied and tuned to many regenerative medicine applications or contraction-related pathological studies. Impact Statement The protocol presented in this article is a new and simple method to quantify contraction forces present in tissue-engineered substitutes. Using finite element analysis, it allows for the measurement of a contraction force rather than a surface reduction as usually provided by other tissue contraction measurement methods. The results shown are in correlation with the current literature relevant to tissue contraction. It can be easily implemented, and hence, this method will open up new avenues to study tissue contraction of living substitutes engineered with various cell types and to optimize culture conditions.

Enhanced healing of burn wounds by multifunctional alginate-chitosan hydrogel enclosing silymarin and zinc ‎oxide ‎nanoparticles

Multifunctional wound dressings have been applied for burn injuries to avoid complications and promote tissue regeneration. In the present study, we fabricated a natural alginate-chitosan hydrogel comprising silymarin and green-synthesized zinc ‎oxide ‎nanoparticles (ZnO NPs). Then, the physicochemical attributes of ZnO NPs and loaded hydrogels were analyzed. Afterward, wound healing efficacy was evaluated in a rat model of full-thickness dermal burn wounds. The findings indicated that ZnO NPs were synthesized via reduction with phytochemicals from Elettaria cardamomum seeds extract. The microscopic images exhibited fairly spherical ZnO NPs (35-45 nm), and elemental analysis verified the relevant composition. The hydrogel, containing silymarin and biosynthesized ZnO NPs, displayed a uniform appearance, smooth surfaces, and a porous structure. Moreover, infrared spectroscopy ‎identified functional groups, confirming the successful loading without adverse interactions. The obtained hydrogel exhibited great water absorption, high porosity, sustainable degradation for several days, and enhanced antioxidant capability of the combined loaded component. In vivo studies revealed faster and superior wound healing, achieving nearly complete closure by day 21. Histopathology confirmed improved cell growth, tissue regeneration, collagen deposition, and neovascularization. It is believed that this multifunctional hydrogel-based wound dressing can be applied for effective burn wound treatment.

Outcomes of dermal substitutes in burns and burn scar reconstruction: A systematic review and meta-analysis

Dermal substitutes have been introduced in burn care to improve wound healing outcomes; however, their use remains limited in standard treatments. This systematic review and meta-analysis aimed to evaluate the outcomes of dermal substitutes in patients with burns and patients requiring burn scar reconstruction and subsequently contribute to optimising the integration of dermal substitutes into clinical practice and reducing the knowledge gap. A comprehensive search across various databases included human studies from peer-reviewed journals on dermal substitutes for deep dermal and full-thickness burns, and scar reconstruction across all ages. Data from comparative trials were extracted, focusing on patient and wound characteristics, treatment specifics, and outcomes related to wound healing and scar quality. Meta-analysis was performed on trials reporting similar post-burn measures, with statistical heterogeneity assessed. Outcomes were presented using mean differences or odds ratios with 95% confidence intervals. A total of 31 comparative trials were included. The overall quality of the studies was considered moderate. The meta-analysis indicated delayed re-epithelialization 4-7 days after treatment with a collagen-elastin matrix compared to split-thickness skin graft in acute burns (-7.30%, p = 0.02). Significant improvement in subjective scar quality was observed with acellular dermal matrix compared to split-thickness skin graft in acute burn wounds 6 months post-operative (-1.95, p <0.01). While acknowledging the initially delayed wound healing, incorporating dermal substitutes into the surgical treatment of burn patients holds promise for enhancing scar quality. However, future research must prioritise outcome measure uniformity, address variations in dermal substitute application, and standardise indications for consistent and effective practices.

Rotating cell culture system-induced injectable self-assembled microtissues with epidermal stem cells for full-thickness skin repair

Epidermal stem cells (EpSCs) are crucial for wound healing and tissue regeneration, and traditional culture methods often lead to their inactivation. It is urgent to increase the yield of high quality EpSCs. In this study, primary EpSCs were isolated and cultured in a serum-free, feeder-free culture system. EpSCs are then expanded in a dynamic 3D environment using a rotating cell culture system (RCCS) with biodegradable porous microcarriers (MC). Over a period of 14 days, the cells self-assembled into microtissues with superior cell proliferation compared to 3D static culture. Immunofluorescence and qPCR analyses consistently showed that the stemness of the 3D microtissues was preserved, especially the COL17A1 associated with anti-aging was highly expressed in RCCS induced microtissues. In vivo experiments demonstrated that the group treated with 3D microtissues loaded with EpSCs showed enhanced early wound healing, and the injectable 3D microtissues were more conducive to maintaining cell viability and differentiation potential. Our study provides valuable insights into the dynamic 3D culture of EpSCs and introduces an injectable therapy using 3D microtissues loaded with EpSCs, which provides a new and effective approach for cell delivery and offering a promising strategy for guiding the regeneration of full-thickness skin defects.

Cost Analysis of Pure Hypochlorous Acid Preserved Wound Cleanser versus Mafenide for the Irrigation of Burn Wounds

Over 40,000 patients in the United States (US) require hospitalization for burns annually. The treatment regimen can cost more than $6,000 a day and requires the use of numerous supplies to ensure the graft takes for successful wound healing. Irrigation of the wound is a critical step for burn treatment, yet little is known about the cost-effectiveness of different irrigation modalities. In a recent study, pure hypochlorous acid preserved wound cleanser (pHA) was shown to be safe and effective compared to mafenide. This study estimated the associated costs of two common wound irrigation modalities, pHA and mafenide solution, for the treatment of patients with burns. In this study, a patient-level Monte Carlo simulation model using data from a randomized control trial (RCT) was used to conduct the cost analysis from the US Hospital perspective. Based upon 100,000 simulated patients, pHA was expected to save $133 ($123 to $144, 10th to 90th percentile) for the hospital compared to using a mafenide solution over 14 days. Adoption of pHA should be considered a cost-saving strategy when treating patients with burns.

Clinical prediction of wound re-epithelisation outcomes in non-severe burn injury using the plasma lipidome

Whilst wound repair in severe burns has received substantial research attention, non-severe burns (<20 % total body surface area) remain relatively understudied, despite causing considerable physiological impact and constituting most of the hospital admissions for burns. Early prediction of healing outcomes would decrease financial and patient burden, and aid in preventing long-term complications from poor wound healing. Lipids have been implicated in inflammation and tissue repair and may play essential roles in burn wound healing. In this study, plasma samples were collected from 20 non-severe burn patients over six weeks from admission, including surgery, and analysed by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy to identify 850 lipids and 112 lipoproteins. Orthogonal projections to latent structures-discriminant analysis was performed to identify changes associated with re-epithelialisation and delayed re-epithelisation. We demonstrated that the lipid and lipoprotein profiles at admission could predict re-epithelisation outcomes at two weeks post-surgery, and that these discriminatory profiles were maintained up to six weeks post-surgery. Inflammatory markers GlycB and C-reactive protein indicated divergent systemic responses to the burn injury at admission. Triacylglycerols, diacylglycerols and low-density lipoprotein subfractions were associated with re-epithelisation (p-value <0.02, Cliff's delta >0.7), whilst high-density lipoprotein subfractions, phosphatidylinositols, phosphatidylcholines, and phosphatidylserines were associated with delayed wound closure at two weeks post-surgery (p-value <0.01, Cliff's delta <-0.7). Further model validation will potentially lead to personalised intervention strategies to reduce the risk of chronic complications post-burn injury.

Unveiling advanced strategies for therapeutic stem cell interventions in severe burn injuries: a comprehensive review

This comprehensive review explores the complex terrain of stem cell therapies as a potential therapeutic frontier in the healing of complicated burn wounds. Serious tissue damage, impaired healing processes, and possible long-term consequences make burn wounds a complex problem. An in-depth review is required since, despite medical progress, existing methods for treating severe burn wounds have significant limitations. Burn wounds are difficult to heal because they cause extensive tissue damage. The challenges of burn injury-induced tissue regeneration and functional recovery are also the subject of this review. Although there is a lot of promise in current stem cell treatments, there are also some limitations with scalability, finding the best way to transport the cells, and finding consistent results across different types of patients. To shed light on how to improve stem cell interventions to heal severe burn wounds, this review covers various stem cell applications in burn wounds and examines these obstacles. To overcome these obstacles, one solution is to enhance methods of stem cell distribution, modify therapies according to the severity of the burn, and conduct more studies on how stem cell therapy affects individual patients. Novel solutions may also be possible through the combination of cutting-edge technologies like nanotechnology and biotechnology. This review seeks to increase stem cell interventions by analyzing present challenges and suggesting strategic improvements. The goal is to provide a more effective and tailored way to repair serious burn wounds.

Elastogenesis in Focus: Navigating Elastic Fibers Synthesis for Advanced Dermal Biomaterial Formulation

Elastin, a fibrous extracellular matrix (ECM) protein, is the main component of elastic fibers that are involved in tissues' elasticity and resilience, enabling them to undergo reversible extensibility and to endure repetitive mechanical stress. After wounding, it is challenging to regenerate elastic fibers and biomaterials developed thus far have struggled to induce its biosynthesis. This review provides a comprehensive summary of elastic fibers synthesis at the cellular level and its implications for biomaterial formulation, with a particular focus on dermal substitutes. The review delves into the intricate process of elastogenesis by cells and investigates potential triggers for elastogenesis encompassing elastin-related compounds, ECM components, and other molecules for their potential role in inducing elastin formation. Understanding of the elastogenic processes is essential for developing biomaterials that trigger not only the synthesis of the elastin protein, but also the formation of a functional and branched elastic fiber network.

A novel hydrogel with inherent antibacterial and hemostatic properties for burn wound healing

The skin is the immune system's first line of defense. Extensive skin burns can lead to tissue necrosis, sepsis, and even death. Anti-infectious care of burn wounds is a major challenge in clinical medicine. However, the extensive use of antibiotics led to the emergence of multi-drug-resistant bacteria and silver dressings with antibacterial effects are also cytotoxic. We used the natural cationic antibacterial agent ε-polylysine (EPL) to graft Epigallocatechin-3-gallate (EGCG) to synthesize EPL-EGCG. Then, we used methacrylated gelatin (GelMA) with arginine-glycine-aspartate-rich acid (RGD) sequence and EPL-EGCG form interpenetrating polymer network hydrogels with excellent swelling properties. The hydrogel's inherent antibacterial properties and photo-cross-linking properties can cover irregular burn wounds and isolate bacteria to prevent infection. In addition, we used polydopamine (PDA) to coat GelMA microspheres with excellent hemostatic efficacy and load platelet-rich plasma (PRP) to enhance the hemostatic efficacy of the microspheres and impart inflammation-regulating functions. The hydrogel showed excellent hemostatic efficacy in rat liver injury and tail vein injury models. In the rat infected burn model, the hydrogel exhibited favorable antimicrobial, pro-angiogenic, and anti-inflammatory phenotype polarization of macrophages. Our study shows that GelMA/EPL-EGCG/GM-PDA@PRP hydrogel application has excellent antibacterial, hemostatic and anti-inflammatory effects, providing a new treatment strategy for wound care before burn skin grafting.

Effect of placental mesenchymal stem cells on promoting the healing of chronic burn wounds

The treatment of chronic burn wounds is difficult in clinical practice. The ideal therapy is required to be continuously explored. Mesenchymal stem cells revolutionize the treatment of many diseases. The placental mesenchymal stem cells (PMSCs) have the characteristics of easy access, strong proliferation ability and multi-directional differentiation potential. The aim of this study was to investigate the potential of PMSCs in chronic burn wound healing. In this study, species of bacteria of 317 patients with chronic burn wounds have been analyzed. Samples of chronic burn wound fluid were collected from representative patients and then co-cultured with cells. In vitro studies showed that chronic burn wound fluid inhibited the proliferation of human keratinocytes and fibroblasts, while PMSCs can counteract the effects of burn wound fluid on inhibiting the proliferation and migration of human keratinocytes and fibroblasts. In addition, in vivo studies showed that a rat chronic burn wound model was successfully created. The expression of MMP-2, MMP-9, MDA, IL-6 and TNF-α in chronic burn wounds was significantly higher than that in acute burn wounds. Finally, the rat chronic burn wound model was used to verify that placental mesenchymal stem cell transplantation increased the wound healing rate, decreased the wound healing time, and promoted wound healing by increasing the thickness of epidermis and promoting the expression of P63 and CK10. The findings provide support for the hypothesis that PMSCs promote the repair of chronic burn wounds and key scientific data for the application of PMSCs as a new method for treating chronic burn wounds.

Photo-Crosslinked Pro-Angiogenic Hydrogel Dressing for Wound Healing

Severe burns are one of the most devastating injuries, in which sustained inflammation and ischemia often delay the healing process. Pro-angiogenic growth factors such as vascular endothelial growth factor (VEGF) have been widely studied for promoting wound healing. However, the short half-life and instability of VEGF limit its clinical applications. In this study, we develop a photo-crosslinked hydrogel wound dressing from methacrylate hyaluronic acid (MeHA) bonded with a pro-angiogenic prominin-1-binding peptide (PR1P). The materials were extruded in wound bed and in situ formed a wound dressing via exposure to short-time ultraviolet radiation. The study shows that the PR1P-bonded hydrogel significantly improves VEGF recruitment, tubular formation, and cell migration in vitro. Swelling, Scanning Electron Microscope, and mechanical tests indicate the peptide does not affect the overall mechanical and physical properties of the hydrogels. For in vivo studies, the PR1P-bonded hydrogel dressing enhances neovascularization and accelerates wound closure in both deep second-degree burn and full-thickness excisional wound models. The Western blot assay shows such benefits can be related to the activation of the VEGF-Akt signaling pathway. These results suggest this photo-crosslinked hydrogel dressing efficiently promotes VEGF recruitment and angiogenesis in skin regeneration, indicating its potential for clinical applications in wound healing.

Healing Potential of the Marine Polysaccharides Carrageenan and Ulvan on Second-Degree Burns

The treatment of second-degree burn wounds presents a significant clinical challenge, often characterized by prolonged healing times and risk of complications. In this study, the wound healing potential of bioactive marine sulfated polysaccharides ulvan and carrageenan formulated in gels at concentrations of 1.5%, 5.0%, and 10% w/w was evaluated. Hairless female SKH-hr2 mice (n = 7 per treatment) with burn-inflamed skin were treated with the polysaccharide-based gels, and the therapeutic efficacy was assessed using a comprehensive array of evaluation methods, including a histopathological analysis, clinical observation, photo-documentation, an image analysis, an evaluation of biophysical skin parameters, and FT-IR spectroscopy. Our findings indicate that the 10% w/w carrageenan gel exhibited significant enhancement in wound healing, particularly in the early stages of the healing process. This was evidenced by the restoration of the α-helix structure of collagen and the configuration of glycosaminoglycans, as demonstrated by FT-IR absorption bands of the skin both in vivo and ex vivo. Furthermore, the 5% w/w ulvan gel also demonstrated notable efficacy in promoting wound healing, particularly in the later stages of the healing process. These results suggest that carrageenan and ulvan gels hold promise for improving the efficiency of wound healing in second-degree burn wounds. Our study contributes to the understanding of the therapeutic potential of marine polysaccharides and provides insights into their mechanism of action in promoting wound healing.

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

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

Formononetin alleviates thermal injury-induced skin fibroblast apoptosis and promotes cell proliferation and migration

The aim of this study was to explore the effect and mechanism of formononetin (FMNT) in thermal-injured fibroblast proliferation, apoptosis, and oxidative stress. After thermal injury, human skin fibroblast (HSF) cells showed inhibited proliferation, migration, extracellular matrix (ECM) synthesis; and increased apoptosis, reactive oxygen species (ROS) production, and inflammation. Specifically, after thermal injury, cell viability, migration distance, and protein levels of collagen I, collagen III, α-SMA, MMP1, and MMP3 were reduced; cell apoptosis rate and TUNEL-positive cell numbers were increased; the levels of Bax and cleaved caspase-3 were elevated, while Bcl-2 level was reduced. Moreover, the thermally injured HSF cells showed increased levels of ROS, MDA, LDH, TNF-α, and IL-1β, and decreased GSH, SOD, GSH-Px, and CAT. FMNT levels can partially eliminate the effects of thermal injury on HSF cells, as shown by promoting thermally injured HSF cell proliferation and migration, and inhibiting cell apoptosis, ROS production, and inflammation. FMNT exerted no significant effect on normal HSF cells. Additionally, the levels of the P13K/AKT/mTOR signaling-related proteins (p-P13K, p-AKT, and p-mTOR) were reduced in thermally injured HSF cells, whereas FMNT could promote p-P13K, p-AKT, and p-mTOR levels. FMNT can partially alleviate the thermal injury-induced inhibition of fibroblast proliferation and migration; FMNT also inhibited the apoptosis, ROS level, and inflammation in thermal-injured cells. The effects of FMNT may be mediated by regulating the P13K/AKT/mTOR pathway.

The Myofibroblast Fate of Therapeutic Mesenchymal Stromal Cells: Regeneration, Repair, or Despair?

Mesenchymal stromal cells (MSCs) can be isolated from various tissues of healthy or patient donors to be retransplanted in cell therapies. Because the number of MSCs obtained from biopsies is typically too low for direct clinical application, MSC expansion in cell culture is required. However, ex vivo amplification often reduces the desired MSC regenerative potential and enhances undesired traits, such as activation into fibrogenic myofibroblasts. Transiently activated myofibroblasts restore tissue integrity after organ injury by producing and contracting extracellular matrix into scar tissue. In contrast, persistent myofibroblasts cause excessive scarring-called fibrosis-that destroys organ function. In this review, we focus on the relevance and molecular mechanisms of myofibroblast activation upon contact with stiff cell culture plastic or recipient scar tissue, such as hypertrophic scars of large skin burns. We discuss cell mechanoperception mechanisms such as integrins and stretch-activated channels, mechanotransduction through the contractile actin cytoskeleton, and conversion of mechanical signals into transcriptional programs via mechanosensitive co-transcription factors, such as YAP, TAZ, and MRTF. We further elaborate how prolonged mechanical stress can create persistent myofibroblast memory by direct mechanotransduction to the nucleus that can evoke lasting epigenetic modifications at the DNA level, such as histone methylation and acetylation. We conclude by projecting how cell culture mechanics can be modulated to generate MSCs, which epigenetically protected against myofibroblast activation and transport desired regeneration potential to the recipient tissue environment in clinical therapies.

Antibacterial and antioxidant phlorizin-loaded nanofiber film effectively promotes the healing of burn wounds

Burns usually result in damage and loss of skin forming irregular wound wounds. The lack of skin tissue protection makes the wound site highly vulnerable to bacterial infections, hindering the healing process. However, commonly used wound dressings do not readily provide complete coverage of irregular wounds compared to regular wounds. Therefore, there is an urgent need to prepare a wound dressing with high antimicrobial efficacy for the administration of drugs to irregular wounds. In this study, a chitosan (CS)/polyvinylpyrrolidone (PVP) composite nanofiber membrane (CS/PVP/Phlorizin) loaded with root bark glycosides (Phlorizin) was developed using an electrostatic spinning technique. The incorporation of phlorizin, a natural antioxidant, into the fiber membranes notably boosted their antimicrobial and antioxidant capabilities, along with demonstrating excellent hydrophilic characteristics. In vitro cellular experiments showed that CS/PVP/Phlorizin increased Hacat cell viability with the presence of better cytocompatibility. In scald wound healing experiments, Phlorizin-loaded nanofibrous membranes significantly promoted re-epithelialization and angiogenesis at the wound site, and reduced the inflammatory response at the wound site. Therefore, the above results indicate that this nanofiber membrane is expected to be an ideal dressing for burn wounds.

Customized Negative Pressure Wound Therapy: Innovative Design in Polyurethane Foam for Complex Burn Reconstruction

The use of negative pressure wound therapy (NPWT) throughout the entire treatment of a burn patient boosts wound healing and recovery. Hand burns require specialized management that enhances wound healing and facilitates early physical rehabilitation. Thus, this article showcases a novel idea of NPWT foam customization that boosts recovery and rehabilitation in patients with hand burns. We present two patients with hand burns treated with NPWT using a customized foam design that allowed for early rehabilitation while providing and optimized recovery. In the two cases presented, the patients required two surgical stages; in the first surgery, debridement of the burns was performed and customized NPWT with instillation was applied, and in the second surgical stage, the bed was reconstructed with partial-thickness skin grafts, which were bolstered with customized conventional NPWT. The management, reconstruction, and rehabilitation were accomplished in under 2 weeks, achieving a remarkable 100% success rate in graft integration during the acute phase on the first attempt. This highlights the effectiveness of incorporating NPWT across all burn treatment phases, expediting recovery and ensuring optimal functional outcomes for patients. Surgeons can customize different NPWT foam shapes that facilitate its use on difficult-to-treat areas, allowing for a faster recovery and better rehabilitation outcomes.

Nanozybiotics: Advancing Antimicrobial Strategies Through Biomimetic Mechanisms

Infectious diseases caused by bacterial, viral, and fungal pathogens present significant global health challenges. The rapid emergence of antimicrobial resistance exacerbates this issue, leading to a scenario where effective antibiotics are increasingly scarce. Traditional antibiotic development strategies are proving inadequate against the swift evolution of microbial resistance. Therefore, there is an urgent need to develop novel antimicrobial strategies with mechanisms distinct from those of existing antibiotics. Nanozybiotics, which are nanozyme-based antimicrobials, mimic the catalytic action of lysosomal enzymes in innate immune cells to kill infectious pathogens. This review reinforces the concept of nanozymes and provides a comprehensive summary of recent research advancements on potential antimicrobial candidates. Initially, nanozybiotics are categorized based on their activities, mimicking either oxidoreductase-like or hydrolase-like functions, thereby highlighting their superior mechanisms in combating antimicrobial resistance. The review then discusses the progress of nanozybiotics in treating bacterial, viral, and fungal infections, confirming their potential as novel antimicrobial candidates. The translational potential of nanozybiotic-based products, including hydrogels, nanorobots, sprays, bandages, masks, and protective clothing, is also considered. Finally, the current challenges and future prospects of nanozybiotic-related products are explored, emphasizing the design and antimicrobial capabilities of nanozybiotics for future applications.

Chlorogenic acid/carboxymethyl chitosan nanoparticle-assisted biomultifunctional hyaluronic acid-based hydrogel scaffolds for burn skin repair

Burns are a prevalent type of injury worldwide, affecting tens of millions of people each year and significantly impacting the physical and psychological well-being of patients. Consequently, prompt treatment of burn wounds is imperative, with oxidative stress and excessive inflammation identified as primary factors contributing to delayed healing. In recent years, there has been growing interest in in situ crosslinked multifunctional hydrogels as a minimally invasive approach for personalized treatment delivery. To address these, a photocrosslinkable methacryloyl hyaluronic acid hydrogel scaffold embedded with chlorogenic acid/carboxymethyl chitosan nanoparticles (CGA/CMCS-HAMA, CCH), was developed for the treatment of burn wounds. The hydrogel prepared degraded by over 50 % by day 20, demonstrating stability and meeting the therapeutic requirements for burn wounds. Leveraging the extracellular matrix-like properties of HAMA and the antioxidant capabilities of CGA/CMCS NPs, this hydrogel demonstrates the ability to locally and continuously scavenge ROS and inhibit lipid peroxidation, inhibiting ferroptosis. Moreover, hydrogels well modulate the expression of macrophage- and fibroblast-associated inflammatory factors. Additionally, the hydrogel promotes cell adhesion and migration, further supporting the healing process. Overall, this innovative approach offers a safe and promising solution for burn wound treatment, addressing drug breakthrough and safety concerns while being adaptable to various irregular wound types.

Copper Ion-Inspired Dual Controllable Drug Release Hydrogels for Wound Management: Driven by Hydrogen Bonds

Bacterial infections and inflammation progression yield huge trouble for the management of serious skin wounds and burns. However, some hydrogel dressing exhibit poor wound-healing capabilities. Additionally, little information is given on the molecular theory of hydrogel gelation mechanisms and drug release performance from drug-polymer network in the water environment. Herein, cationic guar gum (CG) is first mixed with dipotassium glycyrrhizinate (DG), and then crosslinked Cu2+ to strengthen the mechanical strength followed by encapsulating mussel adhesive protein (MAP) as composite dressings. Intriguingly, CG-Cu2+ 0.5-DG10 possessed proper rheological properties and mechanical strength predominantly driven by strong CG-H2O-Cu2+ and Cu2+-CG hydrogen bonding interaction. Weak DG-CG hydrogen bonding only controlled DG release in the initial 4 h, while strong hydrogen bonding is the main force regulating the sustained release of Cu2+ within 48 h. The incorporation of MAP further loosened the tight crosslinking of CG-Cu2+ 0.5-DG10. The screened CG-Cu2+ 0.5-DG10/MAP possessed excellent self-healing, injectability, antibacterial, anti-inflammatory, cell proliferation-promotion activities with high biocompatibility. Therefore, CG-Cu2+ 0.5-DG10/MAP hydrogel expedited wound closure on S. aureus-infected full-thickness skin wound model and lowered necrosis progression to the unburned interspaces on a rat burn model. The results highlight the promising translational potential of Cu2+-inspired hydrogels for the management of burns and infected wounds.

A Composite Application Technique of Single-stage Dermal Templates to Improve Handling and Ease of Use

The "work horse" for the treatment of full-thickness defects of any etiology, including chronic nonhealing wounds and traumatic injuries, is generally autologous split-thickness skin grafts (STSGs), meshed, hand-fenestrated, or a sheet graft. Advancements in skin tissue engineering have allowed for the integration of dermal substitutes to be combined with autologous STSGs, adding valuable options for restoring the skin's complex multilayered structure. Although dermal templates offer a promising avenue for more nuanced reconstruction in certain cases, their application is not without challenges, particularly when they are made from delicate materials. The following technique simplifies the application technique of single-stage dermal templates by using a composite approach. To demonstrate this technique, MatriDerm, a 1-mm-thick bovine collagen-elastin dermal template, is used to enable an STSG to be applied in a one-stage procedure.

Topical diosmetin attenuates nociception and inflammation in a ultraviolet B radiation-induced sunburn model in mice

Burns are a global health problem and can be caused by several factors, including ultraviolet (UV) radiation. Exposure to UVB radiation can cause sunburn and a consequent inflammatory response characterised by pain, oedema, inflammatory cell infiltration, and erythema. Pharmacological treatments available to treat burns and the pain caused by them include nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, antimicrobials and glucocorticoids, which are associated with adverse effects. Therefore, the search for new therapeutic alternatives is needed. Diosmetin, an aglycone of the flavonoid diosmin, has antinociceptive, antioxidant and anti-inflammatory properties. Thus, we evaluated the antinociceptive and anti-inflammatory effects of topical diosmetin (0.01, 0.1 and 1%) in a UVB radiation-induced sunburn model in mice. The right hind paw of the anaesthetised mice was exposed only once to UVB radiation (0.75 J/cm2) and immediately treated with diosmetin once a day for 5 days. The diosmetin antinociceptive effect was evaluated by mechanical allodynia and pain affective-motivational behaviour, while its anti-inflammatory activity was assessed by measuring paw oedema and polymorphonuclear cell infiltration. Mice exposed to UVB radiation presented mechanical allodynia, increased pain affective-motivational behaviour, paw oedema and polymorphonuclear cell infiltration into the paw tissue. Topical Pemulen® TR2 1% diosmetin reduced the mechanical allodynia, the pain affective-motivational behaviour, the paw oedema and the number of polymorphonuclear cells in the mice's paw tissue similar to that presented by Pemulen® TR2 0.1% dexamethasone. These findings indicate that diosmetin has therapeutic potential and may be a promising strategy for treating patients experiencing inflammatory pain, especially those associated with sunburn.

Microneedle Patch for Transdermal Sequential Delivery of KGF-2 and aFGF to Enhance Burn Wound Therapy

Severe burn wounds usually destroy key cells' functions of the skin resulting in delayed re-epithelization and wound regeneration. Promoting key cells' activities is crucial for burn wound repair. It is well known that keratinocyte growth factor-2 (KGF-2) participates in the proliferation and morphogenesis of epithelial cells while acidic fibroblast growth factor (aFGF) is a key mediator for fibroblast and endothelial cell growth and differentiation. However, thick eschar and the harsh environment of a burn wound often decrease the delivery efficiency of fibroblast growth factor (FGF) to the wound site. Therefore, herein a novel microneedle patch for sequential transdermal delivery of KGF-2 and aFGF is fabricated to enhance burn wound therapy. aFGF is first loaded in the nanoparticle (NPaFGF) and then encapsulated NPaFGF with KGF-2 in the microneedle patch (KGF-2/NPaFGF@MN). The result shows that KGF-2/NPaFGF@MN can successfully get across the eschar and sequentially release KGF-2 and aFGF. Additional data demonstrated that KGF-2/NPaFGF@MN achieved a quicker wound closure rate with reduced necrotic tissues, faster re-epithelialization, enhanced collagen deposition, and increased neo-vascularization. Further evidence suggests that improved wound healing is regulated by significantly elevated expressions of hypoxia-inducible factor-1 alpha (HIF-1ɑ) and heat shock protein 90 (Hsp90) in burn wounds. All these data proved that KGF-2/NPaFGF@MN is an effective treatment for wound healing of burns.

Multidisciplinary Management and Autologous Skin Grafting in a Patient with Severe Burns: A Case Study

Background: Heat burns are a prevalent type of trauma. Rapid and effective treatment is crucial for deep burns to minimize complications. Autologous skin grafting is a highly effective treatment for full-thickness burns. A multidisciplinary team plays a vital role in managing burn patients undergoing skin grafting, from initial contact to outpatient follow-up. Case Summary: This case study involves a 56-year-old patient who suffered burns on 60% of his body following an alcohol explosion on an open flame. The patient underwent autologous skin grafting at a Major Burn Center. Initial symptoms included severe pain and immobility, but the patient remained alert and breathed spontaneously. The diagnosis was a loss of epidermis and dermis with burns covering 60-69% of the total body surface area (TBSA) and third-degree burns covering 10% TBSA. Post-discharge, the patient showed significant improvement, with complete healing of the grafts and partial resolution of other lesions. Six months after the intervention, the patient significantly improved his autonomy and mobility. Conclusions: This case highlights the importance of burn prevention and the critical role of multidisciplinary teams in the entire care pathway of burn patients. Appropriate diagnosis, complete treatment, and continuous multidisciplinary support are essential to prevent complications and ensure recovery.

Flexible Sono-Piezo Patch for Functional Sweat Gland Repair through Endogenous Microenvironmental Remodeling

Remodeling the endogenous regenerative microenvironment in wounds is crucial for achieving scarless, functional tissue regeneration, especially the functional recovery of skin appendages such as sweat glands in burn patients. However, current approaches mostly rely on the use of exogenous materials or chemicals to stimulate cell proliferation and migration, while the remodeling of a pro-regenerative microenvironment remains challenging. Herein, we developed a flexible sono-piezo patch (fSPP) that aims to create an endogenous regenerative microenvironment to promote the repair of sweat glands in burn wounds. This patch, composed of multifunctional fibers with embedded piezoelectric nanoparticles, utilized low-intensity pulsed ultrasound (LIPUS) to activate electrical stimulation of the target tissue, resulting in enhanced pro-regenerative behaviors of niche tissues and cells, including peripheral nerves, fibroblasts, and vasculatures. We further demonstrated the effective wound healing and regeneration of functional sweat glands in burn injuries solely through such physical stimulation. This noninvasive and drug-free therapeutic approach holds significant potential for the clinical treatment of burn injuries.

Rynchopeterine inhibits the formation of hypertrophic scars by regulating the miR-21/HIF1AN axis

Hypertrophic scar (HS) is a fibroproliferative skin disease characterized by abnormal wound healing and pathological excessive fibrosis of the skin. Currently, the molecular mechanism of the disease is still largely unknown, and there is no effective drug treatment. In this study, we explored the effect of Rynchopeterine on the formation of HS. HS fibroblasts (HSFs) were isolated from the HS tissues of patients recovering from severe burns. After treating HSFs with different concentrations of Rynchopeterine, CCK-8, EdU, and Annexin V-FITC/PI assays were used to detect the proliferation, apoptosis, and contractile ability of HSFs. RT-qPCR and Western blotting were performed to evaluate the effect of Rynchopeterine on the expression of miR-21 and hypoxia-inducible factor 1-alpha subunit suppressor (HIF1AN). The dual-luciferase reporter gene was used to verify the targeting relationship between miR-21 and HIF1AN. Rynchopeterine reduced the expression of Col1a2, Col3a1, and α-SMA, inhibited proliferation and contraction of HSFs, and increased apoptosis in a dose-dependent manner. miR-21 was highly expressed in HS tissues and HSFs, and Rynchopeterine could inhibit miR-21 expression. Overexpression of miR-21 and knockdown of HIF1AN increased proliferation, activation, contraction, and collagen synthesis of HSFs, and inhibited their apoptosis. In vivo, Rynchopeterine could reduce the collagen content of the dermis and the positive ratio of PCNA and α-SMA. Rynchopeterine is a good therapeutic agent for HS, which up-regulates the expression of HIF1AN by inhibiting miR-21, thereby inhibiting the formation of HS.

The NLRP3 inflammasome in burns: a novel potential therapeutic target

Burns are an underestimated serious injury negatively impacting survivors physically, psychologically and economically, and thus are a considerable public health burden. Despite significant advancements in burn treatment, many burns still do not heal or develop serious complications/sequelae. The nucleotide-binding oligomerization domain-like receptors (NLRs) family pyrin domain-containing 3 (NLRP3) inflammasome is a critical regulator of wound healing, including burn wound healing. A better understanding of the pathophysiological mechanism underlying the healing of burn wounds may help find optimal therapeutic targets to promote the healing of burn wounds, reduce complications/sequelae following burn, and maximize the restoration of structure and function of burn skin. This review aimed to summarize current understanding of the roles and regulatory mechanisms of the NLRP3 inflammasome in burn wound healing, as well as the preclinical studies of the involvement of NLRP3 inhibitors in burn treatment, highlighting the potential application of NLRP3-targeted therapy in burn wounds.

Exosome/antimicrobial peptide laden hydrogel wound dressings promote scarless wound healing through miR-21-5p-mediated multiple functions

Mesenchymal stem cell (MSC)-based therapy is an effective strategy for regenerative therapy. However, safety and ease of use are still issues to be overcome in clinical applications. Exosomes are naturally derived nanoparticles containing bioactive molecules, which serve as ideal cell-free therapeutic modalities. However, issues such as delivery, long-term preservation and activity maintenance of exosomes are other problems that limit their application. In this study, we proposed the use of rapid freeze-dry-thaw macroporous hydrogels for the encapsulation of HucMSC-derived exosomes (HucMSC-Exos) combined with an antimicrobial peptide coating. This exosome-encapsulated hyaluronic acid macroporous hydrogel HD-DP7/Exo can achieve long-term storage and transport by lyophilization and can be rapidly redissolved for treatment. After comprehensively comparing the therapeutic effects of HucMSC-Exos and HucMSC-loaded hydrogels, we found that HucMSC-Exos could also effectively regulate fibroblasts, vascular endothelial cells, and macrophages and inhibit myofibroblast-mediated fibrosis, thus promoting tissue regeneration and inhibiting scar formation in a mouse model of deep second-degree burn infection healing. These properties of lyophilized storage and whole-process-repair make HD-DP7/Exo have potential application value and application prospects.

Barriers and co-designed strategies for the implementation of negative pressure wound therapy in acute pediatric burn care in Australia: A mixed method study

PURPOSE

Pediatric burn injuries are a global clinical issue causing significant morbidity. Early adjunctive negative pressure wound therapy improves re-epithelialization rates in children with burns, yet adoption in acute burn care is inconsistent. This investigation aimed to determine barriers to the implementation of adjunctive negative pressure wound therapy for the acute management of pediatric burns and co-design targeted implementation strategies.

METHODS

A sequential mixed methods design was used explore barriers to adjunctive negative pressure wound therapy implementation in acute pediatric burn care. An online questionnaire was disseminated to healthcare professionals within four major Australian pediatric hospitals, each with a dedicated burns service. Barriers were coded according to the Consolidated Framework for Implementation Research (CFIR). Semi-structured interviews with senior clinicians tailored implementation strategies to local contexts. A stakeholder consensus meeting consolidated implementation strategies and local processes.

RESULTS

Sixty-three healthcare professionals participated in the questionnaire, and semi-structured interviews involved nine senior burn clinicians. We identified eight implementation barriers across all five CFIR domains then co-designed targeted strategies to address identified barriers. Barriers included lack of available resources, limited access to knowledge and information, individual stage of change, patient needs and resources, limited knowledge and beliefs about the intervention, lack of external policies, intervention complexity, and poor implementation planning.

CONCLUSION

Multiple contextual factors affect negative pressure wound therapy uptake in acute pediatric burn settings. Results will inform a multi-state stepped-wedge cluster randomized controlled trial. Additional resources, education, training, updated policies, and guidelines are required for successful implementation. It is anticipated that adjunctive negative pressure wound therapy, in conjunction with tailored implementation strategies, will enhance adoption and sustainability.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry: ACTRN12622000166774. Registered 1 February 2022.

Epidemiological and clinical characteristics of burns in adults: a 6-year retrospective study in a major burn center in Suzhou, China

Background

Burns are a prevalent form of unintentional injury and a significant public health concern in developing countries. We aimed to investigate the epidemiological and clinical characteristics of adult burn patients at a major center in Eastern China.

Methods

This 6-year retrospective study analyzed patients with varying degrees of burns between January 2017 and December 2022 at the Suzhou Burns and Trauma Center. The study extracted demographic, clinical, and epidemiological data from electronic medical records for analysis.

Results

The study included 3,258 adult patients, of which 64.3% were male. The largest age group affected 30-59-year-old adults (63.04%). Scalds were the leading cause of burns (1,346, 41.31%), followed by flames (1,271, 39.01%). The majority of burn hospitalizations were those with moderate burns (1791, 54.97%). The morbidity rate was low at 0.68%, while mortality was strongly associated with age, etiology, and total body surface area. Patients with certain types of burns, such as explosions, hot crush injuries, and electric burns had more operations, longer lengths of hospital stay, and higher costs compared to those with scalds and flame injuries.

Conclusion

Different prevention strategies should be formulated according to different etiologies, ages, and genders.

Genipin crosslinked quaternary ammonium chitosan hydrogels for wound dressings

Bacterial infection can lead to various complications, such as inflammations on surrounding tissues, which can prolong wound healing and thus represent a significant clinical and public healthcare problem. Herein, a report on the fabrication of a novel genipin/quaternized chitosan (CS) hydrogel for wound dressing is presented. The hydrogel was prepared by mixing quaternized CS and genipin under 35 °C bath. The hydrogels showed porous structure (250-500 μm) and mechanical properties (3000-6000 Pa). In addition, the hydrogels displayed self-healing ability and adhesion performance on different substrates. Genipin crosslinked quaternized CS hydrogels showed antibacterial activities againstE. coliandS. aureus. The CCK-8 and fluorescent images confirmed the cytocompatibility of hydrogels by seeding with NIH-3T3 cells. The present study showed that the prepared hydrogel has the potential to be used as wound dressing.

How the combination of alginate and chitosan can fabricate a hydrogel with favorable properties for wound healing

Wound management has always been a significant concern, particularly for men, and the search for effective wound dressings has led to the emergence of hydrogels as a promising solution. In recent years, hydrogels, with their unique properties, have gained considerable importance in wound management. Among the various types of hydrogels, those incorporating chitosan and alginate, two distinct chemical materials, have shown potential in accelerating wound healing. This review aims to discuss the desirable characteristics of an effective wound dressing, explore the alginate/chitosan-based hydrogels developed by different researchers, and analyze their effects on wound healing through in vitro and in vivo assessments. In vitro tests encompass a wide range of evaluations, including swelling capacity, degradation rate, porosity, Fourier Transform Infrared Spectroscopy, X-ray diffraction analysis, moisture vapor transmission rate, release studies, mechanical properties, microscopic observation, antibacterial properties, compatibility assessment, cell adhesion investigation, blood clotting capability, cell migration analysis, water contact angle determination, and structural stability. Furthermore, in vivo assessments encompass the examination of wound closure rate, modulation of gene expression, as well as histopathological and immunohistochemical studies.