Delivery of silver sulfadiazine and adipose derived stem cells using fibrin hydrogel improves infected burn wound regeneration

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

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

A peptide-based pH-sensitive antibacterial hydrogel for healing drug-resistant biofilm-infected diabetic wounds

Diabetic foot ulcers are a significant complication affecting roughly 15% of diabetic patients. These chronic wounds can be incredibly burdensome, leading to high treatment costs, potential amputations, and additional health complications. Microbiological studies reveal that bacterial infections are the primary culprit behind delayed wound healing. To solve the problem of infection at the wound site, the most fundamental thing is to kill the pathogenic bacteria. Herein, a neoteric strategy to construct novel antibacterial hydrogel COA-T3 that combined photosensitizers (PSs) and antimicrobial peptides (AMPs) via covalent coupling was proposed. Hydrogel COA-T3 composed of quaternized chitosan (QCS) and oxidized dextran (OD) was constructed for co-delivery of the photosensitizer TPI-PN and the antimicrobial peptide HHC10. In vitro and in vivo experiments demonstrated remarkable effectiveness of COA-T3 against drug-resistant bacteria. Furthermore, the hydrogel significantly promoted healing of diabetic infected wounds. This enhanced antibacterial activity is attributed to the pH-sensitive release of both PSs and AMPs within the hydrogel. Additionally, COA-T3 exhibits excellent biocompatibility, making it a promising candidate for wound dressing materials. These findings indicated that the COA-T3 hydrogel is a promising wound dressing material for promoting the healing of diabetic foot ulcers by providing an environment conducive to improved wound healing in diabetic patients.

Bacterial cellulose as an ideal potential treatment for burn wounds: A comprehensive review

Burn wound regeneration is a complex process, which has many serious challenges such as slow wound healing, secondary infection, and inflammation. Therefore, it is essential to utilise appropriate biomaterials to accelerate and guide the wound healing process. Bacterial cellulose (BC), a natural polymer synthesised by some bacteria, has attracted much attention for wound healing applications due to its unique properties including excellent physicochemical and mechanical properties, simple purification process, three-dimensional (3D) network structure similar to extracellular matrix, high purity, high water holding capacity and significant permeability to gas and liquid. BC's lack of antibacterial activity significantly limits its biomedical and tissue engineering application, but adding antimicrobial agents to it remarkably improves its performance in tissue regeneration applications. Burn wound healing is a complex long-lasting process. Using biomaterials in wound treatment has shown that they can satisfactorily accelerate wound healing. The purpose of this review is to elaborate on the importance of BC-based structures as one of the most widely used modern wound dressings in the treatment of burn wounds. In addition, the combination of various drugs, agents, cells and biomolecules with BC to expand its application in burn injury regeneration is discussed. Finally, the main challenges and future development direction of BC-based structures for burn wound repair are considered. The four most popular search engines PubMed/MEDLINE, Science Direct, Scopus and Google Scholar were used to help us find relevant papers. The most frequently used keywords were bacterial cellulose, BC-based biocomposite, wound healing, burn wound and vascular graft.

Emulgel based on fish skin collagen-microalgae-silver increased neovascularization and re-epithelialization of full thickness burn in rats

Deep skin burn represents a global morbidity and mortality problem, and the limitation of topical treatment agents has motivated research to development new formulations capable of preventing infections and accelerating healing. The aim of this work was to develop and characterize an emulgel based on collagen (COL) and gelatin (GEL) extracted from fish skin associated with Chlorella vulgaris extract (CE) and silver nitrate (AgNO3). COL and GEL were characterized by physicochemical and thermal analyses; and CE by electrophoresis and its antioxidant capacity. Three emulgels formulations were developed: COL (0.5%) + GEL (2.5%) (E1), COL+GEL+CE (1%) (E2), and COL+GEL+CE + AgNO3 (0.1%) (E3). All formulations were characterized by physicochemical, rheology assays, and preclinical analyses: cytotoxicity (in vitro) and healing potential using a burn model in rats. COL and GEL showed typical physicochemical characteristics, and CE presented 1.3 mg/mL of proteins and antioxidant activity of 76%. Emulgels presented a coherent physicochemical profile and pseudoplastic behavior. Preclinical analysis showed concentration-dependent cytotoxicity against fibroblast and keratinocytes. In addition, all emulgels induced similar percentages of wound contraction and complete wound closure in 28 days. The histopathological analysis showed higher scores for polymorphonuclear cells to E1 and greater neovascularization and re-epithelialization to E3. Then, E3 formulation has potential to improve burn healing, although its use in a clinical setting requires further studies.

The use of nanoparticles in the treatment of infectious diseases and cancer, dental applications and tissue regeneration: a review

The emergence of nanotechnology as a field of study can be traced back to the 1980s, at which point the means to artificially produce, control, and observe matter on a nanometer level was made viable. Recent advancements in technology have enabled us to extend our reach to the nanoscale, which has presented an unparalleled opportunity to directly target biomolecular interactions. As a result of these developments, there is a drive to arise intelligent nanostructures capable of overcoming the obstacles that have impeded the progress of conventional pharmacological methodologies. After four decades, the gradual amalgamation of bio- and nanotechnologies is initiating a revolution in the realm of disease detection, treatment, and monitoring, as well as unsolved medical predicaments. Although a significant portion of research in the field is still confined to laboratories, the initial application of nanotechnology as treatments, vaccines, pharmaceuticals, and diagnostic equipment has now obtained endorsement for commercialization and clinical practice. The current issue presents an overview of the latest progress in nanomedical strategies towards alleviating antibiotic resistance, diagnosing and treating cancer, addressing neurodegenerative disorders, and an array of applications, encompassing dentistry and tuberculosis treatment. The current investigation also scrutinizes the deployment of sophisticated smart nanostructured materials in fields of application such as regenerative medicine, as well as the management of targeted and sustained release of pharmaceuticals and therapeutic interventions. The aforementioned concept exhibits the potential for revolutionary advancements within the field of immunotherapy, as it introduces the utilization of implanted vaccine technology to consistently regulate and augment immune functions. Concurrently with the endeavor to attain the advantages of nanomedical intervention, it is essential to enhance the unceasing emphasis on nanotoxicological research and the regulation of nanomedications' safety. This initiative is crucial in achieving the advancement in medicine that currently lies within our reach.

The efficacy of adipose-derived stem cells in burn injuries: a systematic review

BACKGROUND

Burn injuries can be associated with prolonged healing, infection, a substantial inflammatory response, extensive scarring, and eventually death. In recent decades, both the mortality rates and long-term survival of severe burn victims have improved significantly, and burn care research has increasingly focused on a better quality of life post-trauma. However, delayed healing, infection, pain and extensive scar formation remain a major challenge in the treatment of burns. ADSCs, a distinct type of mesenchymal stem cells, have been shown to improve the healing process. The aim of this review is to evaluate the efficacy of ADSCs in the treatment of burn injuries.

METHODS

A systematic review of the literature was conducted using the electronic databases PubMed, Web of Science and Embase. The basic research question was formulated with the PICO framework, whereby the usage of ADSCs in the treatment of burns in vivo was determined as the fundamental inclusion criterion. Additionally, pertinent journals focusing on burns and their treatment were screened manually for eligible studies. The review was registered in PROSPERO and reported according to the PRISMA statement.

RESULTS

Of the 599 publications screened, 21 were considered relevant to the key question and were included in the present review. The included studies were almost all conducted on rodents, with one exception, where pigs were investigated. 13 of the studies examined the treatment of full-thickness and eight of deep partial-thickness burn injuries. 57,1 percent of the relevant studies have demonstrated that ADSCs exhibit immunomodulatory effects during the inflammatory response. 16 studies have shown improved neovascularisation with the use of ADSCs. 14 studies report positive influences of ADSCs on granulation tissue formation, while 11 studies highlight their efficacy in promoting re-epithelialisation. 11 trials demonstrated an improvement in outcomes during the remodelling phase.

CONCLUSION

In conclusion, it appears that adipose-derived stem cells demonstrate remarkable efficacy in the field of regenerative medicine. However, the usage of ADSCs in the treatment of burns is still at an early experimental stage, and further investigations are required in order to examine the potential usage of ADSCs in future clinical burn care.

Carboxymethyl Chitosan Hydrogels for Effective Wound Healing-An Animal Study

Hydrogels have various applications in medicine, for example, in systems for controlled drug release or as wound dressings, where they provide an appropriate environment for healing and constitute a barrier to microorganisms. The aim of this study was to evaluate the action of carboxymethyl chitosan (CMCS) hydrogels in wound healing therapy in vivo using a laboratory rat model. The hydrogels were formed from aqueous solutions of a CMCS biopolymer via electron beam irradiation, with the presence of a crosslinking agent of poly(ethylene glycol) diacrylate. A histopathological examination of injured tissue, using a model of a hard-to-heal wound, indicated that the CMCS hydrogel supported healing. The new gel dressing, being noncytotoxic, presents great potential in wound treatment, with positive effects on the amount of inflammatory infiltration, young collagen formation, and the degree of epidermalization. A key advantage of the current approach (i.e., using competitive radiation technology for synthesis) is that it includes only one step, with the product being sterilized as it is synthesized. The hydrogel effectively supports wound healing and can serve as a bio-based and biodegradable platform for other medical applications.

Chitosan-based hydrogel wound dressing: From mechanism to applications, a review

As promising biomaterials, hydrogels are widely used in the medical engineering field, especially in wound repairing. Compared with traditional wound dressings, such as gauze and bandage, hydrogel could absorb and retain more water without dissolving or losing its three-dimensional structure, thus avoiding secondary injury and promoting wound healing. Chitosan and its derivatives have become hot research topics for hydrogel wound dressing production due to their unique molecular structure and diverse biological activities. In this review, the mechanism of wound healing was introduced systematically. The mechanism of action of chitosan in the first three stages of wound repair (hemostasis, antimicrobial properties and progranulation), the effect of chitosan deacetylation and the molecular weight on its performance are analyzed. Additionally, the recent progress in intelligent and drug-loaded chitosan-based hydrogels and the features and advantages of chitosan were discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.

Nematic Fibrin Fibers Enabling Vascularized Thrombus Implants Facilitate Scarless Cutaneous Wound Healing

Autologous implantable scaffolds that induce vasculogenesis have shown great potential in tissue regeneration; however, previous attempts mainly relied on cell-laden hydrogel patches using fat tissues or platelet-rich plasma, which are insufficient for generating a uniform vasculature in a scalable manner. Here, implantable vascularized engineered thrombi (IVETs) are presented using autologous whole blood, which potentiate effective skin wound healing by constructing robust microcapillary vessel networks at the wound site. Microfluidic shear stresses enable the alignment of bundled fibrin fibers along the direction of the blood flow streamlines and the activation of platelets, both of which offer moderate stiffness of the microenvironment optimal for facilitating endothelial cell maturation and vascularization. Rodent dorsal skin wounds patched with IVET present superior wound closure rates (96.08 ± 1.58%), epidermis thickness, collagen deposition, hair follicle numbers, and neutrophil infiltration, which are permitted by enhanced microvascular circulation. Moreover, IVET treatment accelerates wound healing by recruiting M2 phenotype macrophages.

3D Printed Chitosan/Alginate Hydrogels for the Controlled Release of Silver Sulfadiazine in Wound Healing Applications: Design, Characterization and Antimicrobial Activity

The growing demand for personalized medicine requires innovation in drug manufacturing to combine versatility with automation. Here, three-dimensional (3D) printing was explored for the production of chitosan (CH)/alginate (ALG)-based hydrogels intended as active dressings for wound healing. ALG hydrogels were loaded with 0.75% w/v silver sulfadiazine (SSD), selected as a drug model commonly used for the therapeutic treatment of infected burn wounds, and four different 3D CH/ALG architectures were designed to modulate the release of this active compound. CH/ALG constructs were characterized by their water content, elasticity and porosity. ALG hydrogels (Young's modulus 0.582 ± 0.019 Mpa) were statistically different in terms of elasticity compared to CH (Young's modulus 0.365 ± 0.015 Mpa) but very similar in terms of swelling properties (water content in ALG: 93.18 ± 0.88% and in CH: 92.76 ± 1.17%). In vitro SSD release tests were performed by using vertical diffusion Franz cells, and statistically significant different behaviors in terms of the amount and kinetics of drugs released were observed as a function of the construct. Moreover, strong antimicrobial potency (100% of growth inhibition) against Staphylococcus aureus and Pseudomonas aeruginosa was demonstrated depending on the type of construct, offering a proof of concept that 3D printing techniques could be efficiently applied to the production of hydrogels for controlled drug delivery.

Quercetin-Embedded Gelastin Injectable Hydrogel as Provisional Biotemplate for Future Cutaneous Application: Optimization and In Vitro Evaluation

Chronic wounds have become an epidemic in millions of patients and result in amputations. In order to overcome this, immediate treatment is a realistic strategy to minimize the risk of complications and aid in the healing rate of the cutaneous wound. Functionalized engineered biomaterials are proven to be a potential approach to embarking on skin wound management. Thus, this study aimed to evaluate the efficacy of a quercetin-embedded gelatin−elastin (Gelastin) injectable hydrogel to act as a provisional biotemplate with excellent physicochemical properties, to be utilized for future cutaneous application. Briefly, the hydrogel was homogenously pre-mixed with genipin (GNP), followed by the incorporation of quercetin (QC). The physicochemical properties comprised the contact angle, swelling ratio, crosslinking degree, enzymatic biodegradation, and water vapor transmission rate (WVTR), as well as chemical characterization. Energy-dispersive X-ray (EDX), XRD, and Fourier transform infra-red (FTIR) analyses were conducted. Briefly, the findings demonstrated that the crosslinked hybrid biomatrix demonstrated better resilience at >100%, a contact angle of >20°, a swelling ratio average of 500 ± 10%, a degradation rate of <0.05 mg/hour, and a successful crosslinking degree (<70%free amine group), compared to the non-crosslinked hybrid biomatrix. In addition, the WVTR was >1500 g/m2 h, an optimal moisture content designed to attain regular cell function and proliferation. The outcomes convey that Gelastin-QC hydrogels deliver the optimum features to be used as a provisional biotemplate for skin tissue engineering purposes.

Bacterial Growth-Induced Tobramycin Smart Release Self-Healing Hydrogel for Pseudomonas aeruginosa-Infected Burn Wound Healing

Burns are a common health problem worldwide and are highly susceptible to bacterial infections that are difficult to handle with ordinary wound dressings. Therefore, burn wound repair is extremely challenging in clinical practice. Herein, a series of self-healing hydrogels (QCS/OD/TOB/PPY@PDA) with good electrical conductivity and antioxidant activity were prepared on the basis of quaternized chitosan (QCS), oxidized dextran (OD), tobramycin (TOB), and polydopamine-coated polypyrrole nanowires (PPY@PDA NWs). These Schiff base cross-links between the aminoglycoside antibiotic TOB and OD enable TOB to be slowly released and responsive to pH. Interestingly, the acidic substances during the bacteria growth process can induce the on-demand release of TOB, avoiding the abuse of antibiotics. The antibacterial results showed that the QCS/OD/TOB/PPY@PDA9 hydrogel could kill high concentrations of Pseudomonas aeruginosa (PA), Staphylococcus aureus, and Escherichia coli in a short time and showed a bactericidal effect for up to 11 days in an agar plate diffusion experiment, while showing good in vivo antibacterial activity. Excellent and long-lasting antibacterial properties make it suitable for severely infected wounds. Furthermore, the incorporation of PPY@PDA endowed the hydrogel with near-infrared (NIR) irradiation assisted bactericidal activity of drug-resistant bacteria, conductivity, and antioxidant activity. Most importantly, in the PA-infected burn wound model, the QCS/OD/TOB/PPY@PDA9 hydrogel more effectively controlled wound inflammation levels and promoted collagen deposition, vascular generation, and earlier wound closure compared to Tegaderm dressings. Therefore, the TOB smart release hydrogels with on-demand delivery are extremely advantageous for bacterial-infected burn wound healing.

Effect of aqueous extract from root and leaf of Sphenocentrum jollyanum pierre on wounds of diabetic rats: Influence on wound tissue cytokines, vascular endothelial growth factor and microbes

ETHNOPHARMACOLOGICAL RELEVANCE

Sphenocentrum jollyanum is a flowering plant of the Menispermaceae family with bright yellow roots and wedged-shaped leaves. The plant is reputed to possess exceptional wound healing properties and used in folkloric medicine to dress chronic wounds.

AIM OF THE STUDY

Wound repair in a hyperglycemic state is known to be impaired and delayed making treatment a difficult challenge. This study sought how the aqueous extracts of root and leaf of Sphenocentrum jollyanum facilitated wound healing by modulating pro-inflammatory cytokines, vascular endothelial growth factor and microbial colonization on excision wound created in diabetic rats.

METHODS

Diabetes (blood glucose >250 mg/dl) was induced by feeding normal rats with high fat diet for 14 days after which intraperitoneal injection of low dose streptozotocin (35 mg/kg b.w.) was administered. Wounds were subsequently created and treatments administered afterwards for 14 days.

RESULTS

Administration of Sphenocentrum jollyanum root and leaf extracts both orally and topically (100 and 200 mg/kg b.w) significantly (p < 0.05) reduced secretion of pro-inflammatory cytokines (TNF-α, IL-6), number of microbial colonies (CFU/ml × 10²), activity of myeloperoxidase and significantly increased growth factor secretion on wounds of the diabetic rats. Histological evaluations of wound tissues of treated diabetic rats revealed matured tissue granulation, presence of new blood vessels, collagen and fibroblast with fewer inflammatory cells.

CONCLUSION

The use of Sphenocentrum jollyanum effectively enhanced wound healing which may be related to constituents identified by GC-MS analysis and can thus, be suggested as a therapeutic agent for diabetic wound management.

Functional Hydrogel Dressings for Treatment of Burn Wounds

The therapy of burns is a challenging clinical issue. Burns are long-term injuries, and numerous patients suffer from chronic pain. Burn treatment includes management, infection control, wound debridement and escharotomy, dressing coverage, skin transplantation, and the use of skin substitutes. The future of advanced care of burn wounds lies in the development of “active dressings”. Hydrogel dressings have been employed universally to accelerate wound healing based on their unique properties to overcome the limitations of existing treatment methods. This review briefly introduces the advantages of hydrogel dressings and discusses the development of new hydrogel dressings for wound healing along with skin regeneration. Further, the treatment strategies for burns, ranging from external to clinical, are reviewed, and the functional classifications of hydrogel dressings along with their clinical value for burns are discussed.

Biodegradable gelatin/silver nanoparticle composite cryogel with excellent antibacterial and antibiofilm activity and hemostasis for Pseudomonas aeruginosa-infected burn wound healing

Burn wounds are susceptible to bacterial infections and are usually accompanied by a large amount of exudate, making the treatment of burn wounds a challenge in the clinic. Here, we developed a biodegradable cryogel with high water absorption and good antibacterial and antibiofilm activity based on gelatin (GT) and silver nanoparticles (Ag NPs) to promote burn wound healing. The porous GT/Ag cryogel had a swelling ratio of up to 4000%, effectively absorbing wound exudate and allowing for gas exchange. Moreover, the GT/Ag cryogel had an excellent killing effect on methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA), which burn wounds are susceptible to, and can effectively remove mature biofilms. In the rat liver defect noncompressible hemorrhage model, GT/Ag cryogels with shape memory performance showed better hemostatic ability than commercial gelatin sponges. Most importantly, the GT/Ag cryogel was more effective than the Tegaderm^TM dressing and GT cryogel in promoting wound contraction, collagen deposition, and angiogenesis and reducing inflammation in a PA-infected burn wound model. In addition, GT/Ag cryogels degraded in the body within 4 weeks, which alleviated the pain of peeling the dressing from the wound. Therefore, GT/Ag cryogels with outstanding antibacterial properties and effective absorption of wound exudates are excellent candidates for wound dressings to promote burn wound repair.

Endogenous Stem Cell-Based In Situ Tissue Regeneration Using Electrostatically Interactive Hydrogel with a Newly Discovered Substance P Analog and VEGF-Mimicking Peptide

The use of chemoattractants to promote endogenous stem cell-based in situ tissue regeneration has recently garnered much attention. This study is the first to assess the endogenous stem cell migration using a newly discovered substance P (SP) analog (SP1) by molecular dynamics simulations as an efficient chemoattractant. Further, a novel strategy based on electrostatic interaction using cationic chitosan (Ch) and anionic hyaluronic acid (HA) to prepare an SP1-loaded injectable C/H formulation without SP1 loss is developed. The formulation quickly forms an SP1-loaded C/H hydrogel in situ through in vivo injection. The newly discovered SP1 is found to possess human mesenchymal stromal cells (hMSCs) migration-inducing ability that is approximately two to three times higher than that of the existing SP. The designed VEGF-mimicking peptide (VP) chemically reacts with the hydrogel (C/H-VP) to sustain the release of VP, thus inducing vasculogenic differentiation of the hMSCs that migrate toward the C/H-VP hydrogel. Similarly, in animal experiments, SP1 attracts a large number of hMSCs toward the C/H-VP hydrogel, after which VP induces vasculogenic differentiation. Collectively, these findings indicate that SP1-loaded C/H-VP hydrogels are a promising strategy to facilitate endogenous stem cell-based in situ tissue regeneration.

Effectiveness of the adipose stem cells in burn wound healing: literature review

Adipose- stem cells (ASCs) have received much attention in the recent years and several articles have investigated the role of these cells on burn wound healing. To understand the outcomes of the ASCs therapy on burn wound healing, a systematic review was performed. This study was conducted by searching in Pubmed, ISI, and Scopus until May 2021. Thirty-six animal studies were included in this study. The findings revealed that although treatment with ASCs somewhat enhanced the healing rate, cultured ASCs on scaffolds or its combination with hydrogels could significantly increase the viability of ASCs and promote rate of healing. However, clinical studies are necessary to gain a better understanding of the role of ASCs in burn wound healing.

Polymeric Hydrogel Scaffolds: Skin Tissue Engineering and Regeneration

Tissue engineering is a novel regenerative approach in the medicinal field that promises the regeneration of damaged tissues. Moreover, tissue engineering involves synthetic and natural biomaterials that facilitate tissue or organ growth outside the body. Not surprisingly, the demand for polymer-based therapeutical approaches in skin tissue defects has increased at an effective rate, despite the pressing clinical need. Among the 3D scaffolds for tissue engineering and regeneration approaches, hydrogel scaffolds have shown significant importance for their use as 3D cross-linked scaffolds in skin tissue regeneration due to their ideal moisture retention property and porosity biocompatibility, biodegradable, and biomimetic characteristics. In this review, we demonstrated the choice of ideal biomaterials to fabricate the novel hydrogel scaffolds for skin tissue engineering. After a short introduction to the bioactive and drug-loaded polymeric hydrogels, the discussion turns to fabrication and characterisation techniques of the polymeric hydrogel scaffolds. In conclusion, we discuss the excellent wound healing potential of stem cell-loaded hydrogels and Nano-based approaches to designing hydrogel scaffolds for skin tissue engineering.

AK, Ramakrishna S, Amirul AAA. Surface Characterization and Physiochemical Evaluation of P(3HB-co-4HB)-Collagen Peptide Scaffolds with Silver Sulfadiazine as Antimicrobial Agent for Potential Infection-Resistance Biomaterial

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] is a bacterial derived biopolymer widely known for its unique physical and mechanical properties to be used in biomedical application. In this study, antimicrobial agent silver sulfadiazine (SSD) coat/collagen peptide coat-P(3HB-co-4HB) (SCCC) and SSD blend/collagen peptide coat-P(3HB-co-4HB) scaffolds (SBCC) were fabricated using a green salt leaching technique combined with freeze-drying. This was then followed by the incorporation of collagen peptides at various concentrations (2.5-12.5 wt.%) to P(3HB-co-4HB) using collagen-coating. As a result, two types of P(3HB-co-4HB) scaffolds were fabricated, including SCCC and SBCC scaffolds. The increasing concentrations of collagen peptides from 2.5 wt.% to 12.5 wt.% exhibited a decline in their porosity. The wettability and hydrophilicity increased as the concentration of collagen peptides in the scaffolds increased. In terms of the cytotoxic results, MTS assay demonstrated the L929 fibroblast scaffolds adhered well to the fabricated scaffolds. The 10 wt.% collagen peptides coated SCCC and SBCC scaffolds displayed highest cell proliferation rate. The antimicrobial analysis of the fabricated scaffolds exhibited 100% inhibition towards various pathogenic microorganisms. However, the SCCC scaffold exhibited 100% inhibition between 12 and 24 h, but the SBCC scaffolds with SSD impregnated in the scaffold had controlled release of the antimicrobial agent. Thus, this study will elucidate the surface interface-cell interactions of the SSD-P(3HB-co-4HB)-collagen peptide scaffolds and controlled release of SSD, antimicrobial agent.

Recent trends on burn wound care: hydrogel dressings and scaffolds

Acute and chronic wounds can cause severe physical trauma to patients and also result in an immense socio-economic burden. Thus, wound management has attracted increasing attention in recent years. However, burn wound management is still a major challenge in wound management. Autografts are often considered the gold-standard for burn care, but their application is limited by many factors. Hence, ideal burn dressings and skin substitute dressings are desirable. With the development of biomaterials and progress of tissue engineering technology, some innovative dressings and tissue engineering scaffolds, such as nanofibers, films, foams and hydrogels, have been widely used in the field of biomedicine, especially in wound management. Among them, hydrogels have attracted tremendous attention with their unique advantages. In this review, we discuss the challenges in burn wound management, several crucial design considerations with respect to hydrogels for burn wound healing, and available polymers for hydrogels in burn wound care. In addition, the potential application and plausible prospect of hydrogels are also highlighted.

Injectable Hydrogels for Chronic Skin Wound Management: A Concise Review

Diabetic foot ulcers (DFU) are a predominant impediment among diabetic patients, increasing morbidity and wound care costs. There are various strategies including using biomaterials have been explored for the management of DFU. This paper will review the injectable hydrogel application as the most studied polymer-based hydrogel based on published journals and articles. The main key factors that will be discussed in chronic wounds focusing on diabetic ulcers include the socioeconomic burden of chronic wounds, biomaterials implicated by the government for DFU management, commercial hydrogel product, mechanism of injectable hydrogel, the current study of novel injectable hydrogel and the future perspectives of injectable hydrogel for the management of DFU.

Sulfonamide drugs: structure, antibacterial property, toxicity, and biophysical interactions

Sulfonamide (or sulphonamide) functional group chemistry (SN) forms the basis of several groups of drug. In vivo sulfonamides exhibit a range of pharmacological activities, such as anti-carbonic anhydrase and anti-t dihydropteroate synthetase allowing them to play a role in treating a diverse range of disease states such as diuresis, hypoglycemia, thyroiditis, inflammation, and glaucoma. Sulfamethazine (SMZ) is a commonly used sulphonamide drug in veterinary medicine that acts as an antibacterial compound to treat livestock diseases such as gastrointestinal and respiratory tract infections. Sulfadiazine (SDZ) is another frequently employed sulphonamide drug that is used in combination with the anti-malarial drug pyrimethamine to treat toxoplasmosis in warm-blooded animals. This study explores the research findings and the work behaviours of SN (SMZ and SDZ) drugs. The areas covered include SN drug structure, SN drug antibacterial activity, SN drug toxicity, and SN environmental toxicity.

Biofunctionalized fibrin gel co-embedded with BMSCs and VEGF for accelerating skin injury repair

Rapid and effective repair of epithelial tissue is desirable for improving the success rate of operation and reducing postoperative complications. Hydrogel is a widely studied wound repair material, especially as a wound dressing for damaged epithelial tissue. Based on the catalytic effect of thrombin on fibrinogen, in this study, a three-dimensional fibrin gel which of adequate epithelial cell compatibility was constructed by using thrombin and fibrinogen under the cross-linking action of calcium ion. Immunofluorescence staining and hematoxylin-eosin (H&E) staining showed that bone marrow mesenchymal stem cell (BMSC) was embedded in fibrin gel. Furthermore, vascular endothelial growth factor (VEGF) was used to induce BMSC to differentiate into CD31+ and vWF+ endothelial cell (EC) in fibrin gel. The results showed that the fibrin gel surface may effectively promote the adhesion and proliferation of EC and smooth muscle cell (SMC). After 15 days of culture, it was found that the BMSC embedded in the hydrogel had differentiated into EC. The results of in vivo skin wound experiment in rats further proved that the fibrin gel containing BMSC could promote wound healing and repair, and showed the potential to promote neovascularization at the injured site. The construction method of hydrogel materials proposed in this study has potential application value in the field of regenerative medicine.

Clinical Translational Potential in Skin Wound Regeneration for Adipose-Derived, Blood-Derived, and Cellulose Materials: Cells, Exosomes, and Hydrogels

Acute and chronic skin wounds due to burns, pressure injuries, and trauma represent a substantial challenge to healthcare delivery with particular impacts on geriatric, paraplegic, and quadriplegic demographics worldwide. Nevertheless, the current standard of care relies extensively on preventive measures to mitigate pressure injury, surgical debridement, skin flap procedures, and negative pressure wound vacuum measures. This article highlights the potential of adipose-, blood-, and cellulose-derived products (cells, decellularized matrices and scaffolds, and exosome and secretome factors) as a means to address this unmet medical need. The current status of this research area is evaluated and discussed in the context of promising avenues for future discovery.

Hydrogel Dressings for the Treatment of Burn Wounds: An Up-To-Date Overview

Globally, the fourth most prevalent devastating form of trauma are burn injuries. Ideal burn wound dressings are fundamental to facilitate the wound healing process and decrease pain in lower time intervals. Conventional dry dressing treatments, such as those using absorbent gauze and/or absorbent cotton, possess limited therapeutic effects and require repeated dressing changes, which further aggravate patients' suffering. Contrariwise, hydrogels represent a promising alternative to improve healing by assuring a moisture balance at the burn site. Most studies consider hydrogels as ideal candidate materials for the synthesis of wound dressings because they exhibit a three-dimensional (3D) structure, which mimics the natural extracellular matrix (ECM) of skin in regard to the high-water amount, which assures a moist environment to the wound. There is a wide variety of polymers that have been used, either alone or blended, for the fabrication of hydrogels designed for biomedical applications focusing on treating burn injuries. The aim of this paper is to provide an up-to-date overview of hydrogels applied in burn wound dressings.

Evaluation of Fibrin-Agarose Tissue-Like Hydrogels Biocompatibility for Tissue Engineering Applications

Generation of biocompatible and biomimetic tissue-like biomaterials is crucial to ensure the success of engineered substitutes in tissue repair. Natural biomaterials able to mimic the structure and composition of native extracellular matrices typically show better results than synthetic biomaterials. The aim of this study was to perform an in vivo time-course biocompatibility analysis of fibrin-agarose tissue-like hydrogels at the histological, imagenological, hematological, and biochemical levels. Tissue-like hydrogels were produced by a controlled biofabrication process allowing the generation of biomechanically and structurally stable hydrogels. The hydrogels were implanted subcutaneously in 25 male Wistar rats and evaluated after 1, 5, 9, and 12 weeks of in vivo follow-up. At each period of time, animals were analyzed using magnetic resonance imaging (MRI), hematological analyses, and histology of the local area in which the biomaterials were implanted, along with major vital organs (liver, kidney, spleen, and regional lymph nodes). MRI results showed no local or distal alterations during the whole study period. Hematology and biochemistry showed some fluctuation in blood cells values and in some biochemical markers over the time. However, these parameters were progressively normalized in the framework of the homeostasis process. Histological, histochemical, and ultrastructural analyses showed that implantation of fibrin-agarose scaffolds was followed by a progressive process of cell invasion, synthesis of components of the extracellular matrix (mainly, collagen) and neovascularization. Implanted biomaterials were successfully biodegraded and biointegrated at 12 weeks without any associated histopathological alteration in the implanted zone or distal vital organs. In summary, our in vivo study suggests that fibrin-agarose tissue-like hydrogels could have potential clinical usefulness in engineering applications in terms of biosafety and biocompatibility.

Fibrin Matrices as (Injectable) Biomaterials: Formation, Clinical Use, and Molecular Engineering

This review focuses on fibrin, starting from biological mechanisms (its production from fibrinogen and its enzymatic degradation), through its use as a medical device and as a biomaterial, and finally discussing the techniques used to add biological functions and/or improve its mechanical performance through its molecular engineering. Fibrin is a material of biological (human, and even patient's own) origin, injectable, adhesive, and remodellable by cells; further, it is nature's most common choice for an in situ forming, provisional matrix. Its widespread use in the clinic and in research is therefore completely unsurprising. There are, however, areas where its biomedical performance can be improved, namely achieving a better control over mechanical properties (and possibly higher modulus), slowing down degradation or incorporating cell-instructive functions (e.g., controlled delivery of growth factors). The authors here specifically review the efforts made in the last 20 years to achieve these aims via biomimetic reactions or self-assembly, as much via formation of hybrid materials.