Gelatin-Based Hybrid Scaffolds: Promising Wound Dressings

Development of carboxymethyl cellulose/gelatin hydrogel loaded with Omega-3 for skin regeneration

Hydrogels have several characteristics, including biocompatibility, physical similarity with the skin's extracellular matrix, and regeneration capacity. Cell migration and proliferation are facilitated by natural polymers such as gelatin (Gel) and carboxymethyl cellulose (CMC). Gelatin dressing acts as a structural framework for cell migration into the wound area, stimulating cell division and promoting granulation tissue formation. Omega-3 fatty acids from fish oil may prevent wound infection and improve the healing of wounds in the early stages. We studied the preparation of wound dressing containing Omega-3 and its ability to heal wounds. In this study, CMC-Gel hydrogels containing different concentrations of Omega-3 were investigated in full-thickness wounds. After the fabrication of the hydrogels by using surfactant (tween 20) and microemulsion method (oil in water), various tests such as SEM, Water uptake evaluation, weight loss, cell viability, blood compatibility, and in vivo study in rat cutaneous modeling during 14 days were performed to evaluate the properties of the fabricated hydrogels. The analysis of the hydrogels revealed that they possess porous structures with interconnected pores, with an average size of 83.23 ± 6.43 μm. The hydrogels exhibited a swelling capacity of up to 60% of their initial weight within 24 h, as indicated by the weight loss and swelling measurements. Cell viability study with the MTT technique showed that no cytotoxicity was observed at the recommended dosage, however, increasing the amount of omega-3 caused hemolysis, cell death, and inhibition of coagulation activity. An in vivo study in adult male rats with a full-thickness model showed greater than 91% improvement of the primary wound region after 2 weeks of treatment. Histological analysis demonstrated Omega-3 in hydrogels, which is a promising approach for topical skin treatment to prevent scar, and has shown efficacy as wound dressing by improving the repair process at the defect site.

Crosslinking gelatin with robust inherent antibacterial natural polymer for wound healing

Gelatin-based biomaterials are widely acknowledged as a promising choice for wound dressings, given their similarity to the extracellular matrix and biocompatibility. However, the challenge of cross-linking gelatin while preserving its biocompatibility and cost-effectiveness persists. This study aimed to enhance the properties of gelatin by incorporating the oxidized lignosulfonate (OLS) biopolymer as an inexpensive and biocompatible natural material. The polyphenolic structure of OLS acts as both a cross-linking agent and an antibacterial component. The OLS/gelatin films were prepared using a casting method with varying weight ratios (0.1, 0.2, 0.3, 0.4, and 0.5 w/w). FTIR analysis confirmed the formation of Schiff-base and hydrogen bonds between gelatin and OLS. The resulting films exhibited enhanced mechanical properties (Young's modulus ∼40 MPa), no cytotoxicity, and excellent cell adhesion and morphology. Antimicrobial tests showed significant activity against Escherichia coli and Staphylococcus aureus, with higher activity against S. aureus (17 mm inhibition zone and 99 % bactericidal rate). In vivo studies in a mouse model demonstrated that the gelatin/0.2OLS dressing significantly improved wound healing, including re-epithelialization, collagen formation, inflammation reduction, and blood vessel density, compared to untreated wounds. These findings suggest that the synthesized novel gelatin/OLS wound dressing has promising healing and antibacterial properties.

The role of adipose tissue-derived stromal cells, macrophages and bioscaffolds in cutaneous wound repair

Skin healing is a complex and dynamic physiological process that follows mechanical alteration of the skin barrier. Under normal conditions, this complex process can be divided into at least three continuous and overlapping phases: an inflammatory reaction, a proliferative phase that leads to tissue reconstruction and a phase of tissue remodeling. Macrophages critically contribute to the physiological cascade for tissue repair. In fact, as the inflammatory phase progresses, macrophage gene expression gradually shifts from pro-inflammatory M1-like to pro-resolutive M2-like characteristics, which is critical for entry into the repair phase. A dysregulation in this macrophage' shift phenotype leads to the persistence of the inflammatory phase. Mesenchymal stromal cells and specifically the MSC-derived from adipose tissue (ADSCs) are more and more use to treat inflammatory diseases and several studies have demonstrated that ADSCs promote the wound healing thanks to their neoangiogenic, immunomodulant and regenerative properties. In several studies, ADSCs and macrophages have been injected directly into the wound bed, but the delivery of exogenous cells directly to the wound raise the problem of cell engraftment and preservation of pro-resolutive phenotype and viability of the cells. Complementary approaches have therefore been explored, such as the use of biomaterials enriched with therapeutic cell to improve cell survival and function. This review will present a background of the current scaffold models, using adipose derived stromal-cells and macrophage as therapeutic cells for wound healing, through a discussion on the potential impact for future applications in skin regeneration. According to the PRISMA statement, we resumed data from investigations reporting the use ADSCs and bioscaffolds and data from macrophages behavior with functional biomaterials in wound healing models. In the era of tissue engineering, functional biomaterials, that can maintain cell delivery and cellular viability, have had a profound impact on the development of dressings for the treatment of chronic wounds. Promising results have been showed in pre-clinical reports using ADSCs- and macrophages-based scaffolds to accelerate and to improve the quality of the cutaneous healing.

Advances of biomacromolecule-based antibacterial hydrogels and their performance evaluation for wound healing: A review

Biomacromolecule hydrogels possess excellent mechanical properties and biocompatibility, but their inability to combat bacteria restricts their application in the biomedical field. With the increasing requirements and demands for hydrogel dressings, wound dressings with antibacterial properties of biomacromolecule hydrogels reinforced by adding antibacterial agents have attracted much attention, and related reviews are emerging. In this paper, the advances of biomacromolecule antibacterial hydrogels (including chitosan, sodium alginate, Hyaluronic acid, cellulose and gelatin) were first overviewed, and the antibacterial agents incorporated into hydrogels were classified (including metals and their derivatives, carbon-based materials, and native compounds). A series of performance evaluations of antibacterial hydrogels in the process of promoting wound healing were then reviewed, including basic properties (mechanical, rheological, injectable and self-healing, etc.), in vitro experiments (hemostasis, antibacterial, anti-inflammatory, anti-oxidation, biocompatibility) and in vivo experiments (in vivo model, histomorphology analysis, cytokines). Finally, the future development of biomacromolecule-based antibacterial hydrogels for wound healing is prospected. This work can provide a useful reference for researchers to prepare practical new wound hydrogel dressings.

A functional hydrogel of dopamine-modified gelatin with photothermal properties for enhancing infected wound healing

Infected skin wound has gradually become a prevalent injury that affects overall health. Currently, biomaterials with good adhesion, efficient antibacterial properties, and angiogenesis are considered as a suitable way to effectively heal infected wound. Herein, a multifunctional hydrogel comprising gelatin, dopamine (DA), and ferric ions (Fe3+) was developed for infected wound healing. The modified gelatin-dopamine (Gel-DA) enhanced adhesive capability. Subsequently introducing ferric ions (Fe3+) to form Gel-DA-Fe3+ hydrogels by Fe3+ and catechol coordination bonds. The designed hydrogels demonstrated multifaceted functionality, encompassing photothermal antibacterial, angiogenesis, and so on. The introduction of DA enhanced the adhesion of Gel-DA-Fe3+ to the skin surface and might serve as a physical barrier to seal wound. Meanwhile, DA and Fe3+ jointly endowed good photothermal effects to composite hydrogels, which could eliminate over 95 % of bacteria. In vitro results revealed that Gel-DA-Fe3+ hydrogels had good biocompatibility and promoted HUVECs migration and tube formation. Furthermore, in vivo studies confirmed that Gel-DA-Fe3+ hydrogels markedly expedited the wound healing of rats through eradicating bacteria, accelerating the deposition of collagen, and promoting angiogenesis. What's more, Gel-DA-Fe3+ hydrogels under near-infrared laser had a more pronounced ability for wound healing. Therefore, Gel-DA-Fe3+ hydrogels had great potential for application in bacteria-infected wound healing.

An Overview of Wound Dressing Materials

Wounds are an increasing global concern, mainly due to a sedentary lifestyle, frequently associated with the occidental way of life. The current prevalence of obesity in Western societies, leading to an increase in type II diabetes, and an elderly population, is also a key factor associated with the problem of wound healing. Therefore, it stands essential to find wound dressing systems that allow for reestablishing the skin integrity in the shortest possible time and with the lowest cost, avoiding further damage and promoting patients' well-being. Wounds can be classified into acute or chronic, depending essentially on the duration of the healing process, which is associated withextent and depth of the wound, localization, the level of infection, and the patient's health status. For each kind of wound and respective healing stage, there is a more suitable dressing. The aim of this review was to focus on the possible wound dressing management, aiming for a more adequate healing approach for each kind of wound.

Materials based on biodegradable polymers chitosan/gelatin: a review of potential applications

Increased mass manufacturing and the pervasive use of plastics in many facets of daily life have had detrimental effects on the environment. As a result, these worries heighten the possibility of climate change due to the carbon dioxide emissions from burning conventional, non-biodegradable polymers. Accordingly, biodegradable gelatin and chitosan polymers are being created as a sustainable substitute for non-biodegradable polymeric materials in various applications. Chitosan is the only naturally occurring cationic alkaline polysaccharide, a well-known edible polymer derived from chitin. The biological activities of chitosan, such as its antioxidant, anticancer, and antimicrobial qualities, have recently piqued the interest of researchers. Similarly, gelatin is a naturally occurring polymer derived from the hydrolytic breakdown of collagen protein and offers various medicinal advantages owing to its unique amino acid composition. In this review, we present an overview of recent studies focusing on applying chitosan and gelatin polymers in various fields. These include using gelatin and chitosan as food packaging, antioxidants and antimicrobial properties, properties encapsulating biologically active substances, tissue engineering, microencapsulation technology, water treatment, and drug delivery. This review emphasizes the significance of investigating sustainable options for non-biodegradable plastics. It showcases the diverse uses of gelatin and chitosan polymers in tackling environmental issues and driving progress across different industries.

The potent osteo-inductive capacity of bioinspired brown seaweed-derived carbohydrate nanofibrous three-dimensional scaffolds

This study aimed to investigate the osteo-inductive capacity of a fucoidan polysaccharide network derived from brown algae on human adipose-derived stem cells (HA-MSCs) for bone regeneration. The physiochemical properties of the scaffold including surface morphology, surface chemistry, hydrophilicity, mechanical stiffness, and porosity were thoroughly characterized. Both in vitro and in vivo measurements implied a superior cell viability, proliferation, adhesion, and osteo-inductive performance of obtained scaffolds compared to using specific osteogenic induction medium with increased irregular growth of calcium crystallites, which mimic the structure of natural bones. That scaffold was highly biocompatible and suitable for cell cultures. Various examinations, such as quantification of mineralization, alkaline phosphatase, gene expression, and immunocytochemical staining of pre-osteocyte and bone markers confirmed that HAD-MSCs differentiate into osteoblasts, even without an osteogenic induction medium. This study provides evidence for the positive relationship and synergistic effects between the physical properties of the decellularized seaweed scaffold and the chemical composition of fucoidan in promoting the osteogenic differentiation of HA-MSCs. Altogether, the natural matrices derived from brown seaweed offers a sustainable, cost-effective, non-toxic bioinspired scaffold and holds promise for future clinical applications in orthopedics.

Self-Powered Electrical Bandage Based on Body-Coupled Energy Harvesting

Self-powered electrical bandages (SEBs), integrated with wearable energy harvesters, can provide an effective and autonomous electrical stimulation (ES) solution for rapid and scarless wound healing. A continuously operating, wireless, and applicable-to-comprehensive-wound ES device is essential for the quick restoration of wounds and convenience. This work illustrates a SEB powered by body-coupled energy harvesting. The SEB continuously treats the wound with 60-Hz sinusoidal electrical potential gained from the coupling of the human body and ambient electrical waves. It is demonstrated that enough level of electrical potential can be applied to the wound, further enhanced by strong capacitive coupling arising from the use of high-permittivity poly(vinylidene fluoride-trifluoroethylene):CaCu3Ti4O12 (P(VDF-TrFE):CCTO) nanocomposite. The potential clinical efficacy of the SEB is illustrated by preclinical analysis of human fibroblasts and mouse wound model, thus confirming the successful expedition of wound recovery. This work suggests a new class of wearable devices to provide ES events and its potential for extension to other conventional wound care materials and device technology.

Silk Sericin and Its Effect on Skin Wound Healing: A State of the Art

Despite the significant progress in wound healing, chronic skin wounds remain a challenge for today's medicine. Due to the growing popularity of natural materials, silk protein-based dressings are gaining more attention in this field. Most studies refer to silk fibroin because sericin has been considered a waste product for years. However, sericin is also worth noting. Sericin-based dressings are mainly studied in cell cultures or animals. Sericin is the dressings' main component or can be included in more complex, advanced biomaterials. Recent studies highlight sericin's important role, noting its biocompatibility, biodegradability, and beneficial effects in skin wound healing, such as antibacterial activity, antioxidant and anti-inflammatory effects, or angiogenic properties. Developing sericin-based biomaterials is often simple, free of toxic by-products, and inexpensive, requiring no highly sophisticated apparatus. As a result, sericin-based dressings can be widely used in wound healing and have low environmental impact. However, the literature in this area is further limited. The following review collects and describes recent studies showing silk sericin's influence on skin wound healing.

Sodium alginate-based nanofibers loaded with Capparis Sepiaria plant extract for wound healing

Burn wounds are associated with infections, drug resistance, allergic reactions, odour, bleeding, excess exudates, and scars, requiring prolonged hospital stay. It is crucial to develop wound dressings that can effectively combat allergic reactions and drug resistance, inhibit infections, and absorb excess exudates to accelerate wound healing. To overcome the above-mentioned problems associated with burn wounds, SA/PVA/PLGA/Capparis sepiaria and SA/PVA/Capparis sepiaria nanofibers incorporated with Capparis sepiaria plant extract were prepared using an electrospinning technique. Fourier-transform infrared spectroscopy confirmed the successful incorporation of the extract into the nanofibers without any interaction between the extract and the polymers. The nanofibers displayed porous morphology and a rough surface suitable for cellular adhesion and proliferation. SA/PVA/PLGA/Capparis sepiaria and SA/PVA/Capparis sepiaria nanofibers demonstrated significant antibacterial effects against wound infection-associated bacterial strains: Pseudomonas aeruginosa, Enterococcus faecalis, Mycobaterium smegmatis, Escherichia coli, Enterobacter cloacae, Proteus vulgaris, and Staphylococcus aureus. Cytocompatibility studies using HaCaT cells revealed the non-toxicity of the nanofibers. SA/PVA/PLGA/Capparis sepiaria and SA/PVA/Capparis sepiaria nanofibers exhibited hemostatic properties, resulting from the synergistic effect of the plant extract and polymers. The in vitro scratch wound healing assay showed that the SA/PVA/Capparis sepiaria nanofiber wound-healing capability is more than the plant extract and a commercially available wound dressing. The wound-healing potential of SA/PVA/Capparis sepiaria nanofiber is attributed to the synergistic effect of the phytochemicals present in the extract, their porosity, and the ECM-mimicking structure of the nanofibers. The findings suggest that the electrospun nanofibers loaded with Capparis sepiaria extract are promising wound dressings that should be explored for burn wounds.

Doxycycline-loaded carboxymethyl cellulose/sodium alginate/gelatin hydrogel: An approach for enhancing pressure ulcer healing in a rat model

Pressure ulcers, or bedsores, are created by areas of the skin under prolonged pressure and can lead to skin and underlying tissue damage. The present study evaluated the effects of carboxymethyl cellulose/sodium alginate/gelatin (CMC/Alg/Gel) hydrogel containing doxycycline (DOX) on improving the healing process of pressure ulcers. The magnet was used to apply pressure on the dorsum skin rat to induce a pressure ulcer model. Then sterile gauze, CMC/Alg/Gel, and CMC/Alg/Gel/1% w/v DOX hydrogels were used to cover the wounds. Blood compatibility, weight loss, cytocompatibility, drug release rate, cell viability, wound closure, and re-epithelialization were evaluated in all animals on the 14th day after treatment. In vivo results and histopathological evaluation showed 56.66% wound closure and the highest re-epithelialization in the CMC/Alg/Gel/1% w/v DOX hydrogel group (14 days after treatment). Furthermore, real-time PCR results indicated that the hydrogel containing DOX significantly decreased the expression of the MMP family consisting of MMP2 and MMP9 mRNA and also increased the expression of vascular endothelial growth factor VEGF mRNA. This study suggested that the addition of DOX, an antibiotic and MMP inhibitor, to hydrogels may be effective in the healing process of pressure ulcers.

Osteoblast responsive biosilica-enriched gelatin microfibrillar microenvironments

Engineering of scaffolds for bone regeneration is often inspired by the native extracellular matrix mimicking its composite fibrous structure. In the present study, we used low loadings of diatomite earth (DE) biosilica to improve the bone regeneration potential of gelatin electrospun fibrillar microenvironments. We explored the effect of increasing the DE content from 1 % to 3 % and 5 %, respectively, on the physico-chemical properties of the fibrous scaffolds denoted FG_DE1, FG_DE3, FG_DE5, regarding the aqueous media affinity, stability under simulated physiological conditions, morphology characteristics, and local mechanical properties at the surface. The presence of biosilica generated composite structures with lower swelling degrees and higher stiffness when compared to gelatin fibers. Increasing DE content led to higher Young modulus, while the stability of the protein matrix in PBS, at 37 °C, over 21 was significantly decreased by the presence of diatomite loadings. The best preosteoblast response was obtained for FG_DE3, with enhanced mineralization during the osteogenic differentiation when compared to the control sample without diatomite. 5 % DE in FG_DE5 proved to negatively influence cells' metabolic activity and morphology. Hence, the obtained composite microfibrillar scaffolds might find application as osteoblast-responsive materials for bone tissue engineering.

Enhancing pressure ulcer healing and tissue regeneration by using N-acetyl-cysteine loaded carboxymethyl cellulose/gelatin/sodium alginate hydrogel

Prolonged pressure on the skin can result in pressure ulcers, which may lead to serious complications, such as infection and tissue damage. In this study, we evaluated the effect of a carboxymethyl cellulose/gelatin/sodium alginate (CMC/Gel/Alg) hydrogel containing N-acetyl-cysteine (NAC) on the healing of pressure ulcers. Pressure ulcers were induced by applying a magnet to the dorsum of rat skin. The wounds were then treated with sterile gauze, ChitoHeal Gel®, and CMC/Gel/Alg hydrogel dressings with or without NAC for the other groups. We evaluated the morphology, weight loss, swelling, rheology, blood compatibility, cytocompatibility, antioxidant capacity, and wound scratch of the prepared hydrogel. MTT assay revealed that the optimum concentration of NAC was 5 mg/ml, which induced higher cell proliferation and viability. Results of the histopathological evaluation showed increased wound closure, and complete re-epithelialization in the hydrogel-containing NAC group compared to the other groups. The CMC/Gel/Alg/5 mg/ml NAC hydrogel dressing showed 84% wound closure at 14 days after treatment. Immunohistochemical results showed a decrease in the level of TNF-α on day 14 compared day 7. Results of the qPCR assay revealed that NAC hydrogel increased the expression of Collagen type I and TGF-β1 and decreased MMP2 and MMP9 mRNA on the 14th day. The results suggest that the CMC/Gel/Alg/5 mg/ml NAC hydrogel with antioxidant properties is an appropriate dressing for wound healing.

Fabrication of gelatin-based antibacterial bilayer wound dressing using direct writing and electrospinning methods

Fabricating a fibrous well-ordered wound dressing for accelerating full-thickness wounds is a desirable treatment vector. Here, through modifications in the material extrusion device and adding a pneumatic-based injection, a material extrusion method for gelatin was introduced with the ability to fabricate 3D structure with repeat layers to support cell activity for the under layer. Furthermore, in the upper layer, the co-electrospinning of PU with gelatin was designed to simultaneously exploit the oxygen permeability and mechanical stability of PU with regenerative properties and collagen-like structure of gelatin. Moreover, zinc oxide nanoparticles (ZnO) was added into the 3D-printed under layer to synergistically benefit from the antibacterial properties of ZnO and the excellent biocompatibility of gelatin. The controllable porosity of the under layer, enabled through the additive manufacturing method, was adjusted to mimic the extracellular matrix of natural tissue with around (127.28 ± 20.70) μm pore size after swelling with smooth fibers. S. aureus, E. coli, Bacillus subtilis, and Pseudomonas with inhibition zone diameters at ∼ 2.14 cm and ∼ 1.96 cm, ∼ 4.01 cm, and ∼ 2.24 cm, respectively. Moreover, the scaffold showed great biocompatibility toward fibroblast cells after 7 days of cell culture with ∼ 89 % cell viability.

Co electrospinning -poly (vinyl alcohol)-chitosan/gelatin-poly (ϵ-caprolacton) nanofibers for diabetic wound-healing application

With the increasing prevalence of diabetes, the healing of diabetic wounds has become a significant challenge for both healthcare professionals and patients. Recognizing the urgent need for effective solutions, it is crucial to develop suitable scaffolds specifically tailored for diabetic wound healing. In line with this objective, we have developed novel hybrid nanofibrous scaffolds by combining polyvinyl alcohol/chitosan (PVA/CS) and gelatin/poly(ε-caprolactone) (Gel/PCL) polymers through a double-nozzle electrospinning technique. In this study, we investigated the influence of the Gel/PCL blend ratio on the properties of the resulting nanofibers. Three different hybrid scaffold structures were examined: Gel/PCL (80:20)-PVA/CS (80:20), Gel/PCL (50:50)-PVA/CS (80:20), and Gel/PVA (20:80)-PVA/CS (80:20). Our findings demonstrate that the electrospun nanofibers of PVA/CS (80:20)-Gel/PCL (80:20) exhibited optimal mechanical performance, with a contact angle of approximately 54° and a diameter of 183 nm. Considering the crucial role of inhibiting bacterial adhesion in the success of implanted materials, we evaluated the cytocompatibility of the hybrid electrospun nanofibers using mouse fibroblast cells (L-929 cells). The in vitro cytotoxicity results obtained from L-929 fibroblast cell culture on the hybrid scaffolds revealed enhanced cell proliferation and appropriate cell morphology on the PVA/CS (80:20)-Gel/PCL (80:20) sample, indicating its capability to support tissue cell integration. Based on the information obtained from this study, the fabricated hybrid scaffold holds great promise for diabetic ulcer healing. Its optimal mechanical properties, suitable contact angle, and favorable cytocompatibility highlight its potential as a valuable tool in the field of diabetic wound healing. The development of such hybrid scaffolds represents a significant step forward in addressing the challenges associated with diabetic wound care.

Acer tegmentosum extract-mediated silver nanoparticles loaded chitosan/alginic acid scaffolds enhance healing of E. coli-infected wounds

This work developed Acer tegmentosum extract-mediated silver nanoparticles (AgNPs) loaded chitosan (CS)/alginic acid (AL) scaffolds (CS/AL-AgNPs) to enhance the healing of E. coli-infected wounds. The SEM-EDS and XRD results revealed the successful formation of the CS/AL-AgNPs. FTIR analysis evidenced that the anionic group of AL (-COO-) and cationic amine groups of CS (-NH3+) were ionically crosslinked to form scaffold (CS/AL). The CS/AL-AgNPs exhibited significant antimicrobial activity against both Gram-positive (G+) and Gram-negative (G-) bacterial pathogens, while being non-toxic to red blood cells (RBCs), the hen's egg chorioallantoic membrane (HET-CAM), and a non-cancerous cell line (NIH3T3). Treatment with CS/AL-AgNPs significantly accelerated the healing of E. coli-infected wounds by regulating the collagen deposition and blood parameters as evidenced by in vivo experiments. Overall, these findings suggest that CS/AL-AgNPs are promising for the treatment of infected wounds.

Designing an antimicrobial film for wound applications incorporating bacteriophages and ε-poly-l-lysine

Alginate-based dressings have been shown to promote wound healing, leveraging the unique properties of alginate. This work aimed to develop and characterize flexible individual and bilayered films to deliver bacteriophages (phages) and ε-Poly-l-lysine (ε-PLL). Films varied in different properties. The moisture content, swelling and solubility increased with higher alginate concentrations. The water vapour permeability, crucial in biomedical films to balance moisture levels for effective wound healing, reached optimal levels in bilayer films, indicating these will be able to sustain an ideal moist environment. The bilayer films showed improved ductility (lower tensile strength and increased elongation at break) compared to individual films. The incorporated phages maintained viability for 12 weeks under vacuum and refrigerated conditions, and their release was sustained and gradual. Antibacterial immersion tests showed that films with phages and ε-PLL significantly inhibited Pseudomonas aeruginosa PAO1 growth (>3.1 Log CFU/cm2). Particle release was influenced by the swelling degree and diffusional processes within the polymer network, providing insights into controlled release mechanisms for particles of varying size (50 nm to 6 μm) and charge. The films developed, demonstrated modulated release capabilities for active agents, and may show potential as controlled delivery systems for phages and wound healing adjuvants.

Modulation of macrophages by a phillyrin-loaded thermosensitive hydrogel promotes skin wound healing in mice

BACKGROUND

Impaired wound healing in traumatic skin injuries remains a severe clinical challenge due to impaired re-vascularization, harmful bacteria infection, and inflammation dysregulation. Macrophages are recognized as prominent immune cells in tissue regeneration and wound healing. Consequently, the modulation of macrophages provides a promising therapeutic target for wound healing disorders. Here, we aimed to explore whether a novel constructed combination of thermosensitive hydrogel Pluronic F-127 (PF-127) and phillyrin (PH, the main active compound of forsythia suspensa) could improve skin wound healing.

METHODS

Firstly, the biological effects of pH on the phenotype and inflammation of macrophages were assessed by flow cytometry and ELISA. The biocompatibility of the PF-127 plus PH combination was investigated on keratinocytes and red blood cells. The biological effect of PF-127/PH hydrogel on the migratory ability of keratinocytes in vitro was evaluated using the scratch and transwell migration assays. In addition,S. aureusandE. coliwere employed to test the antibacterial properties of the PF-127 plus PH combination. Finally, PF-127 plus PH scaffold was appliedto the full-thickness skin defect in mice. Histomorphological evaluation and immunochemistry were performed to explore the wound-healing activity of PF-127/PH hydrogel.

RESULTS

PH can promote the polarization of macrophages from the M1 (pro-inflammatory) phenotype to the M2 (anti-inflammatory) phenotype. The PF-127/PH hydrogel was highly biocompatible and showed a potent stimulative effect on the migration of keratinocytesin vitro. The combination of PF-127 and PH exerted a pronounced antibacterial activity onS. aureusandE. coli in vitro.PF-127/PH hydrogel potently accelerates the healing of full-thickness skin defects by promoting skin cell proliferation, accelerating angiogenesis, and inhibiting inflammation.

CONCLUSIONS

Our study suggests that PF-127/PH hydrogel has excellent potential for treating traumatic skin defects.

Gelatin-based biomaterials and gelatin as an additive for chronic wound repair

Disturbing or disrupting the regular healing process of a skin wound may result in its progression to a chronic state. Chronic wounds often lead to increased infection because of their long healing time, malnutrition, and insufficient oxygen flow, subsequently affecting wound progression. Gelatin-the main structure of natural collagen-is widely used in biomedical fields because of its low cost, wide availability, biocompatibility, and degradability. However, gelatin may exhibit diverse tailored physical properties and poor antibacterial activity. Research on gelatin-based biomaterials has identified the challenges of improving gelatin's poor antibacterial properties and low mechanical properties. In chronic wounds, gelatin-based biomaterials can promote wound hemostasis, enhance peri-wound antibacterial and anti-inflammatory properties, and promote vascular and epithelial cell regeneration. In this article, we first introduce the natural process of wound healing. Second, we present the role of gelatin-based biomaterials and gelatin as an additive in wound healing. Finally, we present the future implications of gelatin-based biomaterials.

Preparation and Investigation of Cellulose Acetate/Gelatin Janus Nanofiber Wound Dressings Loaded with Zinc Oxide or Curcumin for Enhanced Antimicrobial Activity

The skin, as the largest organ, serves as a protective barrier against external stimuli. However, when the skin is injured, wound healing becomes a complex process influenced by physiological conditions, bacterial infections, and inflammation. To improve the process of wound healing, a variety of wound dressings with antibacterial qualities have been created. Electrospun nanofibers have gained significant attention in wound dressing research due to their large specific surface area and unique structure. One interesting method for creating Janus-structured nanofibers is side-by-side electrospinning. This work used side-by-side electrospinning to make cellulose acetate/gelatin Janus nanofibers. Curcumin and zinc oxide nanoparticles were added to these nanofibers. We studied Janus nanofibers' physicochemical characteristics and abilities to regulate small-molecule medication release. Janus nanofibers coated with zinc oxide nanoparticles and curcumin were also tested for antibacterial activity. The Janus nanofibers with specified physicochemical characteristics were successfully fabricated. Nanofibers released small-molecule medicines in a controlled manner. Additionally, the Janus nanofibers loaded with curcumin exhibited excellent antibacterial capabilities. This research contributes to the development of advanced wound dressings for promoting wound healing and combating bacterial infections.

Bringing innovative wound care polymer materials to the market: Challenges, developments, and new trends

The development of innovative products for treating acute and chronic wounds has become a significant topic in healthcare, resulting in numerous products and innovations over time. The growing number of patients with comorbidities and chronic diseases, which may significantly alter, delay, or inhibit normal wound healing, has introduced considerable new challenges into the wound management scenario. Researchers in academia have quickly identified promising solutions, and many advanced wound healing materials have recently been designed; however, their successful translation to the market remains highly complex and unlikely without the contribution of industry experts. This review article condenses the main aspects of wound healing applications that will serve as a practical guide for researchers working in academia and industry devoted to designing, evaluating, validating, and translating polymer wound care materials to the market. The article highlights the current challenges in wound management, describes the state-of-the-art products already on the market and trending polymer materials, describes the regulation pathways for approval, discusses current wound healing models, and offers a perspective on new technologies that could soon reach consumers. We envision that this comprehensive review will significantly contribute to highlighting the importance of networking and exchanges between academia and healthcare companies. Only through the joint of these two actors, where innovation, manufacturing, regulatory insights, and financial resources act in harmony, can wound care products be developed efficiently to reach patients quickly and affordably.

A review on natural biopolymers in external drug delivery systems for wound healing and atopic dermatitis

Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.

Nitric oxide-releasing thiolated starch nanoparticles embedded in gelatin sponges for wound dressing applications

This study introduces a novel wound dressing by combining nitric oxide-releasing thiolated starch nanoparticles (NO-TS NPs) with gelatin. First, starch was thiolated (TS), and then its nanoparticles were prepared (TS NPs). Subsequently, NPs were covalently bonded to sodium nitrite to obtain NO-releasing TS NPs (NO-TS-NPs) that were incorporated into gelatin sponges at various concentrations. The resulting spherical TS NPs had a mean size of 85.42 ± 5.23 nm, which rose to 100.73 ± 7.41 nm after bonding with sodium nitrite. FTIR spectroscopy confirmed S-nitrosation on the NO-TS NPs' surface, and morphology analysis showed well-interconnected pores in all sponges. With higher NO-TS NPs content, pore size, porosity, and water uptake increased, while compressive modulus and strength decreased. Composites exhibited antibacterial activity, particularly against E. coli, with enhanced efficacy at higher NPs' concentrations. In vitro release studies demonstrated Fickian diffusion, with faster NO release in sponges containing more NPs. The released NO amounts were non-toxic to fibroblasts, but samples with fewer NO-TS NPs exhibited superior cellular density, cell attachment, and collagen secretion. Considering the results, including favorable mechanical strength, release behavior, antibacterial and cellular properties, gelatin sponges loaded with 2 mg/mL of NO-TS NPs can be suitable for wound dressing applications.

Formulation of novel bioactive gelatin inspired by cinnamaldehyde for combating multi-drug resistant bacteria: Characterization, molecular docking, pharmacokinetic analyses, and in vitro assessments

This study set out to formulate antibacterial and antioxidant gelatin boosted by cinnamaldehyde for combating multi-drug resistant bacteria previously obtained from chronic wounds. Towards this end, gelatin amine groups were conjugated with carbonyl groups of cinnamaldehyde, producing cinnamyl-gelatin Schiff bases. The physicochemical attributes of cinnamyl-gelatin Schiff bases were probed concerning alterations in chemical structures and microstructures compared to native gelatin. Besides, cinnamyl-gelatin Schiff bases exhibited higher thermal stability than gelatin, with a diminishing in solubility due to increases in hydrophobicity features. Interestingly, cinnamyl-gelatin derivatives exerted antibacterial activities versus multi-drug resistant Gram-negative and Gram-positive bacteria, showing maximum growth inhibition at the highest concentration of cinnamaldehyde incorporated into gelatin. The scavenging activities of gelatin against DPPH and ABTS•+ were promoted in cinnamyl-gelatin derivatives from 11.93 ± 0.6 % to 49.9 ± 2.5 % and 12.54 ± 0.63 % to 49.9 ± 3.12 %, respectively. Remarkably, cinnamyl-gelatin derivatives induced the proliferation of fibroblast cells, implying their prospective applications in tissue engineering. Molecular docking and pharmacokinetic investigations disclosed the potential antibacterial mechanisms of cinnamyl-gelatin derivatives alongside their biopharmaceutical applications. Altogether, these findings suggest that cinnamyl-gelatin derivatives could be utilized to tailor antibacterial-free antibiotics and antioxidant wound dressings against virulent bacteria to promote chronic wound recovery.

Exploring Electrospun Scaffold Innovations in Cardiovascular Therapy: A Review of Electrospinning in Cardiovascular Disease

Cardiovascular disease (CVD) remains the leading cause of mortality worldwide. In particular, patients who suffer from ischemic heart disease (IHD) that is not amenable to surgical or percutaneous revascularization techniques have limited treatment options. Furthermore, after revascularization is successfully implemented, there are a number of pathophysiological changes to the myocardium, including but not limited to ischemia-reperfusion injury, necrosis, altered inflammation, tissue remodeling, and dyskinetic wall motion. Electrospinning, a nanofiber scaffold fabrication technique, has recently emerged as an attractive option as a potential therapeutic platform for the treatment of cardiovascular disease. Electrospun scaffolds made of biocompatible materials have the ability to mimic the native extracellular matrix and are compatible with drug delivery. These inherent properties, combined with ease of customization and a low cost of production, have made electrospun scaffolds an active area of research for the treatment of cardiovascular disease. In this review, we aim to discuss the current state of electrospinning from the fundamentals of scaffold creation to the current role of electrospun materials as both bioengineered extracellular matrices and drug delivery vehicles in the treatment of CVD, with a special emphasis on the potential clinical applications in myocardial ischemia.

Effective wound healing on diabetic mice by adhesive antibacterial GNPs-lysine composited hydrogel

Current trends in wound care research focus on creating dressings for diverse wound types, aiming to effectively control the wound healing process. We proposed a wound dressing composed of oxidized hyaluronic acid and amine gelatin with embedded lysine-modified gelatin nanoparticles (HGel-GNPs-lysine). This dressing improves mechanical properties and reduces degradation rates. The storage modulus for HGel-GNPs-lysine was 3,800 Pa, exceeding that of HGel (1,750 Pa). The positively charged surface of GNPs-lysine effectively eliminated Escherichia coli and Staphylococcus aureus. In a diabetic mice model (C57BL/6), HGel-GNPs-lysine immobilized with basic-fibroblast growth factor promoted granulation tissue thickness and collagen density. Gene expression analysis indicated that HGel-GNPs-lysine reduced inflammation and enhanced angiogenesis. This study highlights that HGel-GNPs-lysine could offer alternative treatment strategies for regulating the inflammatory response at the injury site in wound dressing applications.

Characterization of gelatin-based wound dressing biomaterials containing increasing coconut oil concentrations

This study determined the influence and ideal ratios of various coconut oil (CO) amounts in gelatin (G) based-films as wound dressings since there are limited comparative studies to evaluate the sole effect of increasing CO on protein-based biomaterials. Homogenous films at G:CO ratio of 4:0,4:2,4:3,4:4 (w:w) corresponding to CO-0, CO-2, CO-3, CO-4, respectively, were obtained using solution casting. SEM showed CO caused rougher surfaces decreasing mechanical strength. However, no pores were observed in CO-4 due to bigger clusters of oil improving stretchability compared to CO-3; and durability since aging of CO-4 was >10% lower than CO-0 in aqueous media. FTIR showed triglycerides' band only in CO films with increasing amplitude. Moreover, amide-I of CO-2 was involved in more hydrogen bonding, therefore, CO-2 had the highest melt-like transition temperatures (Tmax) at ∼163 °C while others' were at ∼133 °C; and had more ideal mechanical properties among CO films. XTT showed that increased CO improved 3T3 cell viability as CO-0 significantly decreased viability at 10,50,75,100 μg/mL (p < 0.05), whereas CO-2 and CO-3 within 5-75 μg/mL and CO-4 within 5-100 μg/mL range increased viability ≥100% suggesting proliferation. All CO samples at 25 μg/mL stimulated 3T3 cell migration in Scratch Assay indicating wound healing. CO amounts mainly improved thermal and healing properties of gelatin-based biomaterial. CO-2 was more thermally stable and CO-4 had better influence on cell viability and wound healing than CO-0. Therefore, increased CO ratios, specifically 4:2 and 4:4, G:CO (w:w), in gelatin-based films can be ideal candidates for wound dressing materials.

FTIR, 1H, and 13C NMR Characterization and Antibacterial Activity of the Combination of Euphorbia Honey and Potato Starch

AIM AND OBJECTIVE

In recent years, natural biopolymer (potato starch) hydrogels have been widely used in the field of wound dressing material. This study aimed to develop and characterize a novel antibacterial hydrogel made from potato starch and natural honey.

METHODS

The structure of the composite films was evaluated by Fourier transform infrared (FTIR) and 1H,13C nuclear magnetic resonance (NMR) spectroscopy, and the antibacterial activities were tested by agar diffusion method. FTIR analysis showed chemical interaction between the components of Euphorbia honey (EH) and potato starch hydrogel (PSH).

RESULTS

The 1H-13C NMR and FTIR analyses of EH/PSH confirmed their structure and showed the presence of glucose and hydrocarbon derivatives. After 24 h of incubation, the EH/PSH hydrogel showed good antibacterial activity against three bacterial strains (K.pneumonia, P.mirabilis, and P. aeruginosa) by producing clear inhibition zones of 12.33 ± 1.88 mm, 15.33 ± 0.94, and 10 ± 0 mm, respectively. In addition, K. pneumonia, P. mirabilis, and P. aeruginosa were sensitive to the EH/SPH with a minimum inhibitory concentration (MIC) of 1 %.

CONCLUSION

These results suggest that EH-PS has potential as an alternative candidate to conventional antibiotics.

Advances in Chronic Wound Management: From Conventional Treatment to Novel Therapies and Biological Dressings

Chronic wounds can be classified as diabetic foot ulcers, pressure ulcers, or venous leg ulcers. Chronic wound management has become a threat to clinicians and constitutes a major healthcare burden. The healing process of chronic wounds requires many factors to work in concert to achieve optimal healing. Various treatment options, ranging from hypoxia to infection, have evolved considerably to address the challenges associated with chronic wound healing. The conventional and accelerating treatments for chronic wounds still represent an unmet medical need due to the complex pathophysiology of the chronic wound microenvironment. In clinical settings, traditional chronic wound care practices rely on nonspecific topical treatment, which can reduce pain and alleviate disease progression with varying levels of success but fail to completely cure the wounds. Conventional wound dressings, such as hydrocolloids, gauze, foams, and films, have also shown limited success for the treatment of chronic wounds and only act as a physical barrier and absorb wound exudates. Emerging advances in treatment approaches, including novel therapies (stem cells, microRNAs, and nanocarrier-based delivery systems) and multifunctional biological dressings, have been reported for chronic wound repair. This review summarizes the challenges offered by chronic wounds and discusses recent advancements in chronic wound treatment.

Fabrication of poly (lactic-co-glycolic acid)/gelatin electro spun nanofiber patch containing CaCO3/SiO2 nanocomposite and quercetin for accelerated diabetic wound healing

An open wound or sore on the bottom of the foot caused by diabetes is known as a diabetic foot ulcer. Preventive measures are essential, including consistent foot care and glycemic management. The dangers associated with diabetic foot ulcers can be reduced via early identification and timely treatment. The risk of foot ulcers and limb amputation increases with age and duration of diabetes. Quercetin contains anti-inflammatory and antioxidant properties. Furthermore, the calcium carbonate/silica (CaCO3/SiO2) nanocomposite has a good anti-inflammatory property due to the presence of calcium, which will aid in wound healing. As a result, combining quercetin (plant based anti-inflammatory drug) and CaCO3/SiO2 nanocomposite will boost the wound healing rate. We have synthesized CaCO3/SiO2 nanocomposite in sol-gel method and characterized using XRD, FTIR and TEM. Cell line tests and the MTT assay revealed that the PLGA/gelatin/CaCO3/SiO2/quercetin patch enhanced the proliferation of cells. Its anti-bacterial efficacy against four major bacterial strains often found in wound locations, as well as its water retention, make it an ideal material for diabetic wound healing. In-vivo trials confirms the enhanced diabetic wound healing potential of the patch.

Cellulose Acetate-Based Wound Dressings Loaded with Bioactive Agents: Potential Scaffolds for Wound Dressing and Skin Regeneration

Wound healing and skin regeneration are major challenges in chronic wounds. Among the types of wound dressing products currently available in the market, each wound dressing material is designed for a specific wound type. Some of these products suffer from various shortcomings, such as poor antibacterial efficacy and mechanical performance, inability to provide a moist environment, poor permeability to oxygen and capability to induce cell migration and proliferation during the wound healing process. Hydrogels and nanofibers are widely reported wound dressings that have demonstrated promising capability to overcome these shortcomings. Cellulose acetate is a semisynthetic polymer that has attracted great attention in the fabrication of hydrogels and nanofibers. Loading bioactive agents such as antibiotics, essential oils, metallic nanoparticles, plant extracts, and honey into cellulose acetate-based nanofibers and hydrogels enhanced their biological effects, including antibacterial, antioxidant, and wound healing. This review reports cellulose acetate-based hydrogels and nanofibers loaded with bioactive agents for wound dressing and skin regeneration.

Particle Network Self-Assembly of Similar Size Sub-Micron Calcium Alginate and Polystyrene Particles Atop Glass

Particle-mediated self-assembly, such as nanocomposites, microstructure formation in materials, and core-shell coating of biological particles, offers precise control over the properties of biological materials for applications in drug delivery, tissue engineering, and biosensing. The assembly of similar-sized calcium alginate (CAG) and polystyrene sub-micron particles is studied in an aqueous sodium nitrate solution as a model for particle-mediated self-assembly of biological and synthetic mixed particle species. The objective is to reinforce biological matrices by incorporating synthetic particles to form hybrid particulate networks with tailored properties. By varying the ionic strength of the suspension, the authors alter the energy barriers for particle attachment to each other and to a glass substrate that result from colloidal surface forces. The particles do not show monotonic adsorption trend to glass with ionic strength. Hence, apart from DLVO theory-van der Waals and electrostatic interactions-the authors further consider solvation and bridging interactions in the analysis of the particulate adsorption-coagulation system. CAG particles, which support lower energy barriers to attachment relative to their counterpart polystyrene particles, accumulate as dense aggregates on the glass substrate. Polystyrene particles adsorb simultaneously as detached particles. At high electrolyte concentrations, where electrostatic repulsion is largely screened, the mixture of particles covers most of the glass substrate; the CAG particles form a continuous network throughout the glass substrate with pockets of polystyrene particles. The particulate structure is correlated with the adjustable energy barriers for particle attachment in the suspension.

Synergistic effect of chitosan-alginate composite hydrogel enriched with ascorbic acid and alpha-tocopherol under hypoxic conditions on the behavior of mesenchymal stem cells for wound healing

BACKGROUND

In regenerative medicine, especially skin tissue engineering, the focus is on enhancing the quality of wound healing. Also, several constructs with different regeneration potentials have been used for skin tissue engineering. In this study, the regenerative properties of chitosan-alginate composite hydrogels in skin wound healing under normoxic and hypoxic conditions were investigated in vitro.

METHODS

The ionic gelation method was used to prepare chitosan/alginate (CA) hydrogel containing CA microparticles and bioactive agents [ascorbic acid (AA) and α-tocopherol (TP)]. After preparing composite hydrogels loaded with AA and TP, the physicochemical properties such as porosity, pore size, swelling, weight loss, wettability, drug release, and functional groups were analyzed. Also, the hemo-biocompatibility of composite hydrogels was evaluated by a hemolysis test. Then, the rat bone marrow mesenchymal stem cells (rMSCs) were seeded onto the hydrogels after characterization by flow cytometry. The survival rate was analyzed using MTT assay test. The hydrogels were also investigated by DAPI and H&E staining to monitor cell proliferation and viability. To induce hypoxia, the cells were exposed to CoCl2. To evaluate the regenerative potential of rMSCs cultured on CA/AA/TP hydrogels under hypoxic conditions, the expression of the main genes involved in the healing of skin wounds, including HIF-1α, VEGF-A, and TGF-β1, was investigated by real-time PCR.

RESULTS

The results demonstrated that the prepared composite hydrogels were highly porous, with interconnected pores that ranged in sizes from 20 to 188 μm. The evaluation of weight loss showed that the prepared hydrogels have the ability to biodegrade according to the goals of wound healing. The reduction percentage of CA/AA/TP mass in 21 days was reported as 21.09 ± 0.52%. Also, based on wettability and hemolysis tests of the CA/AA/TP, hydrophilicity (θ = 55.6° and 53.7°) and hemocompatibility with a hemolysis ratio of 1.36 ± 0.19 were evident for them. Besides, MTT assay, DAPI, and H&E staining also showed that the prepared hydrogels provide a suitable substrate for cell growth and proliferation. Finally, based on real-time PCR, increased expression levels of VEGF and TGF-β1 were observed in rMSCs in hypoxic conditions cultured on the prepared hydrogels.

CONCLUSIONS

In conclusion, this study provides evidence that 3D CA/AA/TP composite hydrogels seeded by rMSCs in hypoxic conditions have great potential to improve wound healing.

Fiber-reinforced gelatin/β-cyclodextrin hydrogels loaded with platelet-rich plasma-derived exosomes for diabetic wound healing

Diabetic complications with high-glucose status (HGS) cause the dysregulated autophagy and excessive apoptosis of multiple-type cells, leading to the difficulty in wound self-healing. Herein, we firstly developed fiber-reinforced gelatin (GEL)/β-cyclodextrin (β-CD) therapeutic hydrogels by the modification of platelet-rich plasma exosomes (PRP-EXOs). The GEL fibers that were uniformly dispersed within the GEL/β-CD hydrogels remarkably enhanced the compression strengths and viscoelasticity. The PRP-EXOs were encapsulated in the hydrogels via the covalent crosslinking between the PRP-EXOs and genipin. The diabetic rat models demonstrated that the GEL/β-CD hydrogels and PRP-EXOs cooperatively promoted diabetic wound healing. On the one hand, the GEL/β-CD hydrogels provided the biocompatible microenvironments and active components for cell adhesion, proliferation and skin tissue regeneration. On the other hand, the PRP-EXOs in the therapeutic hydrogels significantly activated the autophagy and inhibited the apoptosis of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs). The activation of autophagy and inhibition of apoptosis in HUVECs and HSFs induced the blood vessel creation, collagen formation and re-epithelialization. Taken together, this work proved that the incorporation of PRP-EXOs in a wound dressing was an effective strategy to regulate autophagy and apoptosis, and provide a novel therapeutic platform for diabetic wound healing.

Supramolecular Responsive Chitosan Microcarriers for Cell Detachment Triggered by Adamantane

Supramolecular responsive microcarriers based on chitosan microspheres were prepared and applied for nonenzymatic cell detachment. Briefly, chitosan microspheres (CSMs) were first prepared by an emulsion crosslinking approach, the surface of which was then modified with β-cyclodextrin (β-CD) by chemical grafting. Subsequently, gelatin was attached onto the surface of the CSMs via the host-guest interaction between β-CD groups and aromatic residues in gelatin. The resultant microspheres were denoted CSM-g-CD-Gel. Due to their superior biocompatibility and gelatin niches, CSM-g-CD-Gel microspheres can be used as effective microcarriers for cell attachment and expansion. L-02, a human fetal hepatocyte line, was used to evaluate cell attachment and expansion with these microcarriers. After incubation for 48 h, the cells attached and expanded to cover the entire surface of microcarriers. Moreover, with the addition of adamantane (AD), cells can be detached from the microcarriers together with gelatin because of the competitive binding between β-CD and AD. Overall, these supramolecular responsive microcarriers could effectively support cell expansion and achieve nonenzymatic cell detachment and may be potentially reusable with a new cycle of gelatin attachment and detachment.

Photothermal effective CeO2NPs combined in thermosensitive hydrogels with enhanced antibacterial, antioxidant and vascularization performance to accelerate infected diabetic wound healing

Chronic diabetic wound healing remains a formidable challenge due to susceptibility to bacterial infection, excessive oxidative stress, and poor angiogenesis. To address these issues, a sodium alginate (SA) based photothermal hydrogel dressing with multifunction was fabricated to facilitate wound treatment. Ceria nanoparticles (CeO2NPs) was synthesized, and their antibacterial performance by near-infrared light triggered photothermal effects was first studied and verified in this work. In addition, to release CeO2NPs to achieve antioxidation and pro-vascularization, thermosensitive gelatin (Gel) was utilized to embed the nanoparticles in advance and then composited in SA hydrogel networks. SA network was finally strengthened by acid soaking to form partially crystalline regions to act as natural crosslinkers. Results showed that the Gel/SA/CeO2 hydrogel displayed temperature-responsive release of CeO2NPs, significant antibacterial and antioxidative activity, as well as the ability to remove without injury and promote infected diabetic wound healing with low cytotoxicity, according to antibacterial investigations, cell studies, and in vivo animal studies. This research offers not only a successful method for quickening the healing of diabetic wounds but also a fresh approach to the general use of CeO2NPs.

Animal tissue-derived biomaterials for promoting wound healing

The skin serves as the primary barrier between the human body and external environment, and is therefore susceptible to damage from various factors. In response to this challenge, animal tissue-derived biomaterials have emerged as promising candidates for wound healing due to their abundant sources, low side-effect profiles, exceptional bioactivity, biocompatibility, and unique extracellular matrix (ECM) mimicry. The evolution of modern engineering technology and therapies has allowed these animal tissue-derived biomaterials to be transformed into various forms and modified to possess the necessary properties for wound repair. This review provides an overview of the wound healing process and the factors that influence it. We then describe the extraction methods, important properties, and recent practical applications of various animal tissue-derived biomaterials. Our focus then shifts to the critical properties of these biomaterials in skin wound healing and their latest research developments. Finally, we critically examine the limitations and future prospects of biomaterials generated from animal tissues in this field.

Agar/gelatin hydro-film containing EGF and Aloe vera for effective wound healing

In the current study, we produced a hydro-film dressing for the treatment of chronic wounds. The hydro-film structure was composed of gelatin cross-linked with citric acid, agar and Aloe vera extract (AV); additionally epidermal growth factor (EGF) was loaded to promote wound healing. Due to the excellent hydrogel-forming ability of gelatin, the obtained hydro-film was able to swell 884 ± 36% of its dry weight, which could help controlling wound moisture. To improve gelatin mechanical properties, polymer chains were cross-linked with citric acid and agar, reaching an ultimate tensile strength that was in the highest range of human skin. In addition, it showed a slow degradation profile that resulted in a remaining weight of 28 ± 8% at day 28. Regarding, biological activity, the addition of AV and citric acid provided the ability to reduce human macrophage activation, which could help reverse the permanent inflammatory state of chronic wounds. Moreover, loaded EGF, together with the structural AV of the hydro-film, promoted human keratinocyte and fibroblast migration, respectively. Furthermore, the hydro-films presented excellent fibroblast adhesiveness, so they could be useful as provisional matrices for cell migration. Accordingly, these hydro-films showed suitable physicochemical characteristics and biological activity for chronic wound healing applications.

Thermosensitive hydrogel coupled with sodium ascorbyl phosphate promotes human umbilical cord-derived mesenchymal stem cell-mediated skin wound healing in mice

Poor survival and restricted function of transplanted stem cells are regarded as limiting their efficacy in wound recovery greatly. Consequently, it is necessary to identify innovative therapeutic strategies to solve these issues. Firstly, the biological effect of PF-127 hydrogel alone and in combination with SAP on the survival, and migration of cultured HUCMSCs was assessed by cell viability, apoptosis, and scratch wound assays. S. aureus and E. coli were used to evaluate the antibacterial activity of PF-127 plus SAP combination. Further, the ability of HUCMSCs-conditioned medium (HUCMSCs-CM) to promote the angiogenesis and migration of human umbilical vein endothelial cells (HUVECs) in vitro was evaluated using tube formation and transwell migration assays. Finally, the HUCMSCs embedded in PF-127 plus SAP scaffold were administered onto mice's excisional cutaneous wound bed. Histological and immunohistochemical analyses were employed to investigate the wound healing capacity as well as cellular responses of PF-127/HUCMSCs/SAP hydrogel. PF-127 showed cytotoxicity on HUCMSCs, whereas the addition of SAP significantly promoted cell viability and alleviated apoptosis of HUCMSCs encapsulated in PF-127 hydrogel in vitro. SAP supplementation substantially abrogated the inhibiting effect of PF-127 on the migration of HUCMSCs in vitro. The combination of PF-127 and SAP exerted an obvious bacteriostatic function on S. aureus and E. coli. Moreover, the co-treatment with SAP could remarkably enhance the stimulative effect of HUCMSCs-CM on the angiogenesis and migration of HUVECs in vitro. PF-127 combined SAP-embedded HUCMSCs transplantation resulted in a potently accelerated wound healing process, promoted the number of proliferating cells and newly formed blood vessels, as well as enhanced expression of vascular endothelial growth factor. PF-127 coupled with SAP contributes to HUCMSCs-mediated traumatic wound closure in mice by promoting cell survival, antibacterial action, and angiogenesis. Our results offered a theoretical foundation for the clinical treatment of traumatic skin defects.

Polymer-Based Hydrogel Loaded with Honey in Drug Delivery System for Wound Healing Applications

Excellent wound dressings should have crucial components, including high porosity, non-toxicity, high water absorption, and the ability to retain a humid environment in the wound area and facilitate wound healing. Unfortunately, current wound dressings hamper the healing process, with poor antibacterial, anti-inflammatory, and antioxidant activity, frequent dressing changes, low biodegradability, and poor mechanical properties. Hydrogels are crosslinked polymer chains with three-dimensional (3D) networks that have been applicable as wound dressings. They could retain a humid environment on the wound site, provide a protective barrier against pathogenic infections, and provide pain relief. Hydrogel can be obtained from natural, synthetic, or hybrid polymers. Honey is a natural substance that has demonstrated several therapeutic efficacies, including anti-inflammatory, antibacterial, and antioxidant activity, which makes it beneficial for wound treatment. Honey-based hydrogel wound dressings demonstrated excellent characteristics, including good biodegradability and biocompatibility, stimulated cell proliferation and reepithelization, inhibited bacterial growth, and accelerated wound healing. This review aimed to demonstrate the potential of honey-based hydrogel in wound healing applications and complement the studies accessible regarding implementing honey-based hydrogel dressing for wound healing.

Natural Polymer-Based Thin Film Strategies for Skin Regeneration in Lieu of Regenerative Dentistry

Wound healing (WH) is a complex and dynamic process that comprises of a series of molecular and cellular events that occur after tissue injury. The injuries of the maxillofacial and oral region caused by trauma or surgery result in undesirable WH such as delayed wound closure and formation of scar tissue. Skin tissue engineering (TE)/regeneration is an emerging approach toward faster, superior, and more effective resolution of clinically significant wounds effectively. A multitude of TE principles approaches are being put to action for the fabrication of hydrogels, electrospun sheets, 3D scaffolds, and thin films that can be used as wound dressings materials, sutures, or skin substitutes. Thin films are advantageous over other materials owing to their flexibility, ability to provide a barrier against external contamination, easy gaseous exchange, and easy monitoring of wounds. This review focuses on wound-dressing films and their significance and discusses various fabrication techniques. In addition, we explore various natural biopolymers that can be used for fabrication of skin TE materials. Impact Statement In this review article, critical evaluations of natural polymers used in skin regeneration were discussed. Further, the fabrication technology of the 2D and 3D material in wound healing were discussed.

Bio-Inspired Low-Cost Fabrication of Stretchable, Adhesive, Transparent, and Multi-Functionalized Joint Wound Dressings

Ideal joint wound dressings should not only promote wound healing and have good mechanical properties including stretchability and adhesion but also possess functions such as sterilization or motion monitoring. The multiple characteristic requirements have greatly limited the material's alternative, resulting in research on functional joint wound dressings falling far short of market demand. Therefore, low-cost, comprehensive designs need to be developed. Herein, inspired by the spiral arteries in the endometrium, alginate-based helical fibers were introduced into polyacrylamide/gelatin (PAM-Gel) to obtain composite polymer membranes, realizing a combination of both mechanical and functional properties. Large scale (100 m) and high-throughput (10 times higher than literature) fabrication of helical microfibers were first achieved, ensuring the low cost of fiber preparation. The composite film had adequate stretchability (>300% strain), adhesion strength (14 kPa), high transparency, and good biocompatibility. The helical fibers could be easily functionalized without affecting the mechanical properties of the dressings, thus broadening the range of materials available for joint dressings. After different treatments of the helical fibers, controlled drug release and joint motion monitoring were realized. Therefore, this helical microfiber composite membrane design achieved low-cost preparation, good mechanical properties, and functionalities including healing promotion, drug release, and motion monitoring ability, demonstrating application potential.

Physical Properties and pH Environment of Foam Dressing Containing Eclipta prostrata Leaf Extract and Gelatin

Eclipta prostrata (E. prostrata) has several biological activities, including antibacterial and anti-inflammatory activities, that improve wound healing. It is well known that physical properties and pH environment are crucial considerations when developing wound dressings containing medicinal plant extracts in order to create an appropriate environment for wound healing. In this study, we prepared a foam dressing containing E. prostrata leaf extract and gelatin. Chemical composition was verified using Fourier-transform infrared spectroscopy (FTIR) and pore structure was obtained using scanning electron microscopy (SEM). The physical properties of the dressing, including absorption and dehydration properties, were also evaluated. The chemical properties were measured to determine the pH environment after the dressing was suspended in water. The results revealed that the E. prostrata dressings had a pore structure with an appropriate pore size (313.25 ± 76.51 µm and 383.26 ± 64.45 µm for the E. prostrata A and E. prostrata B dressings, respectively). The E. prostrata B dressings showed a higher percentage of weight increase in the first hour and a faster dehydration rate in the first 4 h. Furthermore, the E. prostrata dressings had a slightly acidic environment (5.28 ± 0.02 and 5.38 ± 0.02 for the E. prostrata A and E. prostrata B dressings at 48 h, respectively).

A 3D printed hydrogel to promote human keratinocytes' spheroid-based growth

Tissue engineering uses cells and biomaterials to develop bioartificial tissue substitutes for different purposes. For example, although several skin models have been developed for pharmaceutical and cosmetic research and skin wound healing, there are few studies on 3D cultures of keratinocytes in 3D printed scaffolds. So, this work aimed to develop a 3D-printed hydrogel scaffold to promote human keratinocyte growth. Mesh 3D scaffolds were printed using an extrusion-based method with a 20% gelatin/5% alginate hydrogel, where HaCaT cells were cultured for 7 days. Scaffolds kept their structure for over 1 week, and their stiffness only decreased after 7 days, showing good mechanical and structural characteristics and biodegradability (27% weight lost). Viable keratinocytes (MTT assay) are aggregated into spheroids, a 3D model capable of mimicking in vivo cell properties and phenotypes. Spheroids were formed on 47% of scaffolds pores and grew over time, showing promising cell proliferation. F-actin staining showed cells' irregular and interconnected shapes and organization over time. This method offers an easy and inexpensive solution for keratinocyte spheroid formation, which may be helpful in tissue engineering as a cell delivery system, for pharmacological or basic research, or wound healing medical applications.

A Brief Review on Cerium Oxide (CeO2NPs)-Based Scaffolds: Recent Advances in Wound Healing Applications

The process of wound healing is complex and involves the interaction of multiple cells, each with a distinct role in the inflammatory, proliferative, and remodeling phases. Chronic, nonhealing wounds may result from reduced fibroblast proliferation, angiogenesis, and cellular immunity, often associated with diabetes, hypertension, vascular deficits, immunological inadequacies, and chronic renal disease. Various strategies and methodologies have been explored to develop nanomaterials for wound-healing treatment. Several nanoparticles such as gold, silver, cerium oxide and zinc possess antibacterial properties, stability, and a high surface area that promotes efficient wound healing. In this review article, we investigate the effectiveness of cerium oxide nanoparticles (CeO₂NPs) in wound healing-particularly the effects of reducing inflammation, enhancing hemostasis and proliferation, and scavenging reactive oxygen species. The mechanism enables CeO₂NPs to reduce inflammation, modulate the immunological system, and promote angiogenesis and tissue regeneration. In addition, we investigate the efficacy of cerium oxide-based scaffolds in various wound-healing applications for creating a favorable wound-healing environment. Cerium oxide nanoparticles (CeO₂NPs) exhibit antioxidant, anti-inflammatory, and regenerative characteristics, enabling them to be ideal wound healing material. Investigations have shown that CeO₂NPs can stimulate wound closure, tissue regeneration, and scar reduction. CeO₂NPs may also reduce bacterial infections and boost wound-site immunity. However, additional study is needed to determine the safety and efficacy of CeO₂NPs in wound healing and their long-term impacts on human health and the environment. The review reveals that CeO₂NPs have promising wound-healing properties, but further study is needed to understand their mechanisms of action and ensure their safety and efficacy.

Natural Polymeric Composites Derived from Animals, Plants, and Microbes for Vaccine Delivery and Adjuvant Applications: A Review

A key element in ensuring successful immunization is the efficient delivery of vaccines. However, poor immunogenicity and adverse inflammatory immunogenic reactions make the establishment of an efficient vaccine delivery method a challenging task. The delivery of vaccines has been performed via a variety of delivery methods, including natural-polymer-based carriers that are relatively biocompatible and have low toxicity. The incorporation of adjuvants or antigens into biomaterial-based immunizations has demonstrated better immune response than formulations that just contain the antigen. This system may enable antigen-mediated immunogenicity and shelter and transport the cargo vaccine or antigen to the appropriate target organ. In this regard, this work reviews the recent applications of natural polymer composites from different sources, such as animals, plants, and microbes, in vaccine delivery systems.

Multifunctional, Adhesive, and PDA-Coated Bioactive Glass Reinforced Composite Hydrogel for Regenerative Wound Healing

Effective wound management imposes several challenges in clinical outcomes due to the complexity of the wound microenvironment, bacterial infections, impaired angiogenesis, aggravated inflammation, and enduring pain. In addition, adhesion on wet biological tissue is another extremely challenging task. Addressing all the issues is necessary for an effective wound healing process. Herein, we developed a unique multifunctional, adhesive composite hydrogel composed of gelatin, chitosan, polydopamine-coated bioactive glass (BG), and curcumin-capped silver nanoparticles (Cur-AgNPs) to target the multifaceted complexity of the wound. The PDA-coated BG serves multiple purposes: (1) adhesivity: catechol groups of PDA and Ca ion released from BG chelate the group present in the hydrogel network and surrounding tissues, (2) angiogenesis: promotes vascularization due to the release of Si from BG, and (3) BG also serves as the "reservoir" for the pain-relieving diclofenac sodium drug with a sustained-release behavior. Cur-AgNPs provide excellent bactericidal and anti-inflammatory properties to the composite hydrogel. In situ application of the composite hydrogel could serve the purpose of a "skin biomimetic" and work as a barrier along with bactericidal properties to inhibit the microbial growth. The multifunctional composite hydrogel (MCH) targeted multiple aspects of wound repair including pain alleviation, elimination of microbes (up to 99%), reduced inflammation, high adhesivity, and increased angiogenesis for effective skin regeneration. The MCH showed excellent wound healing potential as significant wound closure was observed at day 7 and also significantly upregulated the expression of crucial genes involved in the skin regeneration process along with increasing vascularization in the wound area.