Chitosan-alginate sponge: preparation and application in curcumin delivery for dermal wound healing in rat

Therapeutic applications of natural products in the management of venous diseases: a comprehensive review

The occurrence of venous diseases among adults is approximately 77% in females and 57% in males. These conditions are prevalent, progressive disorders that significantly affect individuals socially, physically, and psychologically, often resulting in various venous abnormalities that hinder effective blood circulation in the lower limbs. This review provides a comprehensive overview of venous diseases, focusing on their pathophysiology, symptoms, causes, risk factors, diagnosis, and complications. The symptoms associated with venous diseases are diverse and can include pain, heaviness, swelling, ulcers, and skin changes. Risk factors such as age, obesity, hormonal influences, and genetic predispositions are discussed in relation to their contribution to disease progression. The therapeutic modalities for managing venous diseases are explored, with a particular emphasis on natural products in alleviating symptoms and improving vascular health. Natural compounds, i.e., flavonoids, play a vital role in the circulatory system, supporting blood vessels and promoting healthy blood flow, in addition to their vasoprotective, antioxidant, anti-inflammatory, and anti-platelet properties. Overall, the ongoing research efforts on the efficacy of natural products will significantly enhance the management of several venous diseases in the coming years.

Bio-inspired aFGF modification functionalized piezoelectric chitosan films for promoting scald wound healing

The application of acidic fibroblast growth factor (aFGF) has shown great potential in the treatment of scald or burn wounds with high morbidity and mortality, especially in promoting the repair of deep partial-thickness wounds. However, its short half-life and instability in vivo do pose challenges for clinical application. Herein, two kinds of bio-inspired modified piezoelectric chitosan (CS) films, namely heparin-coated CS film (HCS) and polydopamine-coated CS film (DCS), are facially fabricated and adopted as controlled-release platforms for local delivery of aFGF. Polydopamine or heparin layers serve as a bridge grafting on chitosan films, facilitating the loading of aFGF and enabling controlled release of aFGF from the piezoelectric film through intermolecular interactions. Additionally, these layers enhance the hydrophilicity and antibacterial properties of the bare CS film due to their inherent biological activities. Furthermore, the polydopamine coating imparts photothermal activity to the CS film. The in vivo experiments ascertain that the synergetic effect of the controlled-released aFGF and low temperature photothermal therapy collectively accelerate scald wound healing outcomes within 14 days by facilitating granulation formation, collagen deposition, re-epithelialization and angiogenesis. This study opens up new possibilities for the development of multifunctional chitosan-based wound dressings and the creation of innovative drug delivery platforms.

High-efficiency antibacterial calcium alginate/lysozyme/AgNPs composite sponge for wound healing

Infection poses a significant barrier to effective wound repair, leading to increased inflammatory responses that ultimately result in incomplete and prolonged wound healing. To address this challenge, numerous antibacterial ingredients have been incorporated into dressings to inhibit wound infection. Our previous work demonstrated that lysozyme/silver nanoparticles (LYZ/AgNPs) complexes, prepared using an eco-friendly one-step aqueous method, exhibited excellent antibacterial efficacy with favorable biosafety. To further explore its potential application in advancing wound healing, calcium alginate (CA) with good porosity, water absorption, and water retention capacities was formulated with LYZ/AgNPs to prepare composite sponge (CA/LYZ/AgNPs). As expected, in vivo experiments involving full-thickness skin wound and scald wound healing experiments demonstrated that CA-LYZ-AgNPs composite sponges with excellent biocompatibility exhibited remarkable antibacterial activity against gram-positive bacteria, gram-negative bacteria and fungi, and outperformed the wound healing process efficacy of other commercially available AgNPs-loaded wound dressings. In summary, this work introduces a CA/LYZ/AgNPs sponge featuring exceptional antibacterial efficacy and biocompatibility, thus holding promising potential in wound care applications.

An Insight into Biodegradable Polymers and their Biomedical Applications for Wound Healing

Biodegradable polymers, encompassing both natural and synthetic polymers, have demonstrated efficacy as carriers for synthetic drugs, natural bioactive molecules, and inorganic metals. This is due to their ability to control the release of these substances. As a result, various advanced materials, such as nanoparticle- loaded hydrogels, nanofibrous scaffolds, and nanocomposites, have been developed. These materials have shown promise in enhancing processes, such as cell proliferation, vascular angiogenesis, hair growth, and wound healing management. Natural polymers, including hyaluronic acid, collagen, chitosan, gelatin, and alginate, as well as synthetic polymers like polylactic acid, polyglycolic acid, polylactic co-glycolic acid, and PCA, have significant potential for promoting wound healing. This study examines the advancements in biodegradable polymers for wound healing, specifically focusing on each polymer and its distinctive formulations. It also discusses the in vitro experiments conducted using different cell lines, as well as the in vivo studies that explore the numerous uses of these polymers in wound healing. The discussion also included the exploration of modifications or combinations of several polymers, as well as surface changes, in order to produce synergistic effects and address the limitations of individual polymers. The goal was to expedite the healing process of different chronic wounds. Due to this, there have been notable advancements in the technological use of polymeric mixes, including biodegradable polymer-based scaffolds, which have accelerated the process of wound healing.

Chitosan bioactive glass scaffolds for in vivo subcutaneous implantation, toxicity assessment, and diabetic wound healing upon animal model

This study aims to develop chitosan-bioactive glass (BG) scaffolds for diabetic wound healing, toxicity valuation, and subcutaneous implantation in animals for biocompatibility assessment. The scaffolds were prepared by lyophilization technique. In specific BG without sodium (Na), composited with chitosan for better biological activities. The equipped scaffolds were studied for their physiochemical, biological, in vitro and in vivo performances. The chitosan and chitosan-BG (Na free) scaffolds show reliable biocompatibility, cytocompatibility, anti-oxidant, and tissue regeneration. The biocompatibility, toxicity assessments, and diabetic skin wound healing experiments were examined through in vivo studies using Sprague Dawley rats. The extracted tissue samples were analyzed using hematoxylin-eosin- (H and E) and Masson's trichrome staining. Further, tissue excised after scaffold implantation declared non-toxic, non-allergic, and anti-inflammatory nature of chitosan scaffolds. Moreover, the total ribonucleic acid (RNA) expression levels were measured using reverse transcription-polymerase chain reaction (RT-PCR) for the scaffolds against vascular endothelial growth factor (VEGF), and collagen type one (Col-1) primers. Admirably, the scaffolds achieved the best level of skin wound healing via tissue regeneration by increasing epithetical cell formation and collagen deposition. Thus, the biocompatibility, non-toxicity, anti-inflammatory, and wound healing efficiency proved that the chitosan-BG (Na free) scaffold can be readily substantial for wound healing.

Chitosan sponges loaded with metformin and microalgae as dressing for wound healing: A study in diabetic bio-models

Among the conditions caused by diabetes, the diabetic foot is a significant public health problem due to its delayed healing process. That makes it essential to design, manufacture, and apply auxiliary dressings during healing. In this work, chitosan sponges were developed and evaluated as wound dressings. Metformin, fucoidan, and exopolysaccharide from Porphyridium purpureum algae were loaded into the sponges and studied as healing promoters. The composite sponges were physicochemically, morphologically, and thermally characterized, allowing us to determine the chemical mechanisms involved in the sponge formation. The mechanical analysis demonstrated that sponge composites have shape memory and good mechanical performance under compression stress, showing a compressive strength above 30 kPa. These results correlated with the materials' porosity, influencing the swelling capacity that reached a maximum of 70 %. The morphology of materials was observed by SEM, resulting in folded films with surface porosity. The results of the biocompatibility tests confirmed that the materials are not cytotoxic or hemolytic and have good antibacterial activity. In vivo wound healing evaluation showed that metformin-loaded chitosan sponges regenerated skin tissue after 21 days of treatment, highlighting the rate of healing provided when exopolysaccharide was added to promote tissue regeneration, which can be corroborated by histological analysis. These results make chitosan sponge compounds promising dressings for diabetic foot wound treatment.

Recent advances in chitosan-based materials; The synthesis, modifications and biomedical applications

The attention to polymer-based biomaterials, for instance, chitosan and its derivatives, as well as the techniques for using them in numerous scientific domains, is continuously rising. Chitosan is a decomposable naturally occurring polymeric material that is mostly obtained from seafood waste. Because of its special ecofriendly, biocompatible, non- toxic nature as well as antimicrobial properties, chitosan-based materials have received a lot of interest in the field of biomedical applications. The reactivity of chitosan is mainly because of the amino and hydroxyl groups in its composition, which makes it further fascinating for various uses, including biosensing, textile finishing, antimicrobial wound dressing, tissue engineering, bioimaging, gene, DNA and drug delivery and as a coating material for medical implants. This study is an overview of the different types of chitosan-based materials which now a days have been fabricated by applying different techniques and modifications that include etherification, esterification, crosslinking, graft copolymerization and o-acetylation etc. for hydroxyl groups' processes and acetylation, quaternization, Schiff's base reaction, and grafting for amino groups' reactions. Furthermore, this overview summarizes the literature from recent years related to the important applications of chitosan-based materials (i.e., thin films, nanocomposites or nanoparticles, sponges and hydrogels) in different biomedical applications.

Curcumin-infused nanostructured lipid carriers: a promising strategy for enhancing skin regeneration and combating microbial infection

BACKGROUND

Curcumin is a biomolecule that can be extracted from the Curcuma longa that has been shown to have the potential to aid skin wound healing. It has been studied for its anti-inflammatory and antioxidant properties, which may help to reduce swelling and promote tissue repair. However, curcumin has low solubility in water, which can limit its absorption and bioavailability. Encapsulating it in lipid nanoparticles may help to increase its absorption, leading to improved bioavailability.

METHODS

Curcumin-loaded nanostructure lipid nanocarriers (CURC-NLCs) were prepared and characterized. Also, the phenolic, flavonoid contents, antioxidant and antimicrobial efficacy against gram-positive and gram-negative bacteria were investigated. Furthermore, in vivo rabbit animal model was used to test its regenerative capacity and wound-healing efficiency.

RESULTS

The CURC-NLCs significantly increased the content of phenolic and flavonoid compounds compared to curcumin, resulting in a dramatic increase in antioxidant activity. CURC-NLCs also showed a potent inhibitory effect on Gram-positive, Gram-negative, and fungi, two times higher than curcumin. CURC-NLCs showed a higher potential to fasten the wound healing of full-thickness skin injuries as it resulted in 1.15- and 1.9-fold higher wound closure at the first week of injury compared to curcumin and control, respectively (p < 0.0001).

CONCLUSION

These results suggest that CURC-NLCs have an excellent potential to promote skin regeneration, which could be attributed to its antioxidant and broad-spectrum antimicrobial effect.

Curcumin promotes skin wound healing by activating Nrf2 signaling pathways and inducing apoptosis in mice

Background/aim

Curcumin may have potential as a therapy for wound healing, but the underlying mechanism remains unclear. It is not known whether curcumin can promote wound healing by activating Nrf2 signaling pathway and inducing apoptosis. This study determined the role of Nrf2 signaling pathway and apoptosis in curcumin-promoting skin wound healing.

Materials and methods

The full-thickness skin defect model of mice was made and randomly divided into a control group and a curcumin group. The mice in the curcumin group and in the control group received respectively a daily topical treatment of Vaseline cream with or without 5 mg curcumin. The wound healing of mice was observed daily. The mice in two groups were killed respectively on postinjury days 3, 7, and 14, and the wound tissues were collected, with 5 mice in each group. Pathological change and formation of collagen fibers were observed by HE and Masson staining respectively. The expression of caspase-3 was observed by immunohistochemistry. Western blot was used to examine the protein levels of Nrf2 and HO-1, and ELISA assay and colorimetry assay were used to check the contents of ROS, MDA, SOD, and GSH.

Results

The wound healing rates of curcumin group were higher than those of control group (p < 0.05), and the pathological changes were also significantly better than those in the control group (p < 0.05). Collagen fiber synthesis in curcumin group was higher than that in control group (p < 0.05). Moreover, the expression of caspase-3 in curcumin group was higher than that in control group on 7th day post wound (p < 0.05). Furthermore, the levels of ROS and MDA in curcumin were lower than those in control group (p < 0.05), and the level of Nrf2, HO-1, SOD and GSH were higher than those in control group (p < 0.05).

Conclusion

Curcumin improves skin wound healing by activating the Nrf2 signaling pathway and inducing apoptosis in mice.

In Vitro and In Vivo Efficacy of Topical Dosage Forms Containing Self-Nanoemulsifying Drug Delivery System Loaded with Curcumin

The external use of curcumin is rare, although it can be a valuable active ingredient in the treatment of certain inflammatory diseases. The aim of our experimental work was to formulate topical dosage forms containing curcumin for the treatment of atopic dermatitis. Curcumin has extremely poor solubility and bioavailability, so we have tried to increase it with the usage of self-emulsifying drug delivery systems. Creams and gels were formulated using penetration-enhancing surfactants and gelling agents. The release of the drug from the vehicle and its penetration through the membrane were determined using a Franz diffusion cell. An MTT cytotoxicity and in vitro antioxidant assays were performed on HaCaT cell line. The in vivo anti-inflammatory effect of the preparations was tested by measuring rat paw edema. In addition, we examined the degree of inflammation induced by UV radiation after pretreatment with the cream and the gel on rats. For the gels containing SNEDDS, the highest penetration was measured after half an hour, while for the cream, it took one hour to reach the maximum concentration. The gel containing Pemulen TR-1 showed the highest drug release. It was determined that the curcumin-containing preparations can be safely applied on the skin and have antioxidant effects. The animal experiments have proven the effectiveness of curcumin-containing topical preparations.

Synthesis and Design of a Synthetic-Living Material Composed of Chitosan, Calendula officinalis Hydroalcoholic Extract, and Yeast with Applications as a Biocatalyst

Design and development of materials that couple synthetic and living components allow taking advantage of the complexity of biological systems within a controlled environment. However, their design and fabrication represent a challenge for material scientists since it is necessary to synthesize synthetic materials with highly specialized biocompatible and physicochemical properties. The design of synthetic-living materials (vita materials) requires materials capable of hosting cell ingrowth and maintaining cell viability for extended periods. Vita materials offer various advantages, from simplifying product purification steps to controlling cell metabolic activity and improving the resistance of biological systems to external stress factors, translating into reducing bioprocess costs and diversifying their industrial applications. Here, chitosan sponges, functionalized with Calendula officinalis hydroalcoholic extract, were synthesized using the freeze-drying method; they showed small pore sizes (7.58 μm), high porosity (97.95%), high water absorption (1695%), and thermal stability, which allows the material to withstand sterilization conditions. The sponges allowed integration of 58.34% of viable Saccharomyces cerevisiae cells, and the cell viability was conserved 12 h post-process (57.14%) under storage conditions [refrigerating temperature (4 °C) and without a nutrient supply]. In addition, the synthesized vita materials conserved their biocatalytic activity after 7 days of the integration process, which was evaluated through glucose consumption and ethanol production. The results in this paper describe the synthesis of complex vita materials and demonstrate that biochemically modified chitosan sponges can be used as a platform material to host living and metabolically active yeast with diverse applications as biocatalysts.

Local administration of curcumin-loaded nanoparticles enhances periodontal repair in vivo

The aim was to assess the influence of local application of curcumin-loaded nanoparticles on an experimental model of periodontal repair. Periodontitis was induced by ligatures on both lower first molars of rats. After 15 days, ligatures were removed ("treatment") and animals were randomly allocated to three experimental groups (n = 8/group): (i) 0.05 mg/ml curcumin-loaded nanoparticles, (ii) empty nanoparticles (vehicle control), and (iii) sterile saline (negative control). Experimental treatments were administered locally on days 0, 3, 5, 7, 9, and 11 after ligature removal. Animals were euthanized at 7 and 14 days. Bone repair was assessed by microcomputer tomography (µCT). Histological sections were stained with hematoxylin/eosin (H/E), Picrosirius Red, and Masson's trichrome. Expression of Runx-2 was studied by immunohistochemistry. Gene expression of Itgam, Arg1, and Inos was assessed by RT-qPCR. At 7 days, there was increased gene expression of Itgam and Arg1 and of the relative expression of Arg1/Inos in curcumin-treated animals, but no difference in any other outcomes. At 14 days, curcumin-loaded nanoparticles significantly increased bone repair and collagen content, as well as the number of osteocytes, percentage of extracellular matrix, and expression of Runx2. The results demonstrate that local administration of curcumin-loaded nanoparticles enhanced tissue repair in an experimental model of periodontal repair. Nanoparticle-encapsulated curcumin enhances early post-treatment repair of periodontal tissues.

Microwave-Treated Physically Cross-Linked Sodium Alginate and Sodium Carboxymethyl Cellulose Blend Polymer Film for Open Incision Wound Healing in Diabetic Animals-A Novel Perspective for Skin Tissue Regeneration Application

This study aimed at developing the microwave-treated, physically cross-linked polymer blend film, optimizing the microwave treatment time, and testing for physicochemical attributes and wound healing potential in diabetic animals. Microwave-treated and untreated films were prepared by the solution casting method and characterized for various attributes required by a wound healing platform. The optimized formulation was tested for skin regeneration potential in the diabetes-induced open-incision animal model. The results indicated that the optimized polymer film formulation (MB-3) has significantly enhanced physicochemical properties such as high moisture adsorption (154.6 ± 4.23%), decreased the water vapor transmission rate (WVTR) value of (53.0 ± 2.8 g/m²/h) and water vapor permeability (WVP) value (1.74 ± 0.08 g mm/h/m²), delayed erosion (18.69 ± 4.74%), high water uptake, smooth and homogenous surface morphology, higher tensile strength (56.84 ± 1.19 MPa), and increased glass transition temperature and enthalpy (through polymer hydrophilic functional groups depicting efficient cross-linking). The in vivo data on day 16 of post-wounding indicated that the wound healing occurred faster with significantly increased percent re-epithelialization and enhanced collagen deposition with optimized MB-3 film application compared with the untreated group. The study concluded that the microwave-treated polymer blend films have sufficiently enhanced physical properties, making them an effective candidate for ameliorating the diabetic wound healing process and hastening skin tissue regeneration.

Alginates Combined with Natural Polymers as Valuable Drug Delivery Platforms

Alginates (ALG) have been used in biomedical and pharmaceutical technologies for decades. ALG are natural polymers occurring in brown algae and feature multiple advantages, including biocompatibility, low toxicity and mucoadhesiveness. Moreover, ALG demonstrate biological activities per se, including anti-hyperlipidemic, antimicrobial, anti-reflux, immunomodulatory or anti-inflammatory activities. ALG are characterized by gelling ability, one of the most frequently utilized properties in the drug form design. ALG have numerous applications in pharmaceutical technology that include micro- and nanoparticles, tablets, mucoadhesive dosage forms, wound dressings and films. However, there are some shortcomings, which impede the development of modified-release dosage forms or formulations with adequate mechanical strength based on pure ALG. Other natural polymers combined with ALG create great potential as drug carriers, improving limitations of ALG matrices. Therefore, in this paper, ALG blends with pectins, chitosan, gelatin, and carrageenans were critically reviewed.

Histological and Molecular Evidence of the Positive Performance of Glycerol-Plasticized Chitosan-Alginate Membranes on Skin Lesions of Hyperglycemic Mice

The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment (CTSF); hyperglycemic animals with 0.9% saline solution topical treatment (DMSF) and hyperglycemic animals with glycerol-plasticized chitosan-alginate membrane topical treatment (DMCAM). On post-wound day three, the DMCAM group presented a lower number of leukocytes, mature mastocytes, a higher number of vessels (p < 0.05), and active mastocytes (p < 0.05) when compared to the CTSF and DMSF groups. There were no differences regarding the distribution, deposition, organization, and thickness of collagen fibers. On day 7 there were no differences in the analysis of fibroblasts, mastocytes, and TGF−β1 and VEGF expressions among the groups. Regarding collagen fibers, the DMCAM group presented slight red-orange birefringence when compared to the CTSF and DMSF groups. On day 14 there was a slight concentration of thinner elastic fibers for the DMCAM group, with a greater reorganization of papillary skin and improved red-orange birefringence collagen fibers, as well as net-shaped orientation, similar to intact skin. In addition, improved elastic fiber organization distributed in the entire neo-dermis and a larger presence of elaunin fibers were observed, in a similar pattern found in the intact skin. The use of CAM in cutaneous lesions boosted tissue repair since there was a smaller number of inflammatory cells and mastocytes, and an improvement in collagen deposition and collagen fibers. These results demonstrate the high potential of plasticized chitosan-alginate membrane for skin wound dressing of hyperglycemic patients.

Bio-Multifunctional Sponges Containing Alginate/Chitosan/Sargassum Polysaccharides Promote the Healing of Full-Thickness Wounds

Creation of bio-multifunctional wound dressings with potent hemostatic, antibacterial, anti-inflammatory, and angiogenesis features for bolstering the healing of full-thickness wounds is sought after for clinical applications. We created bio-multifunctional composite sponges by coupling alginate and chitosan with Sargassum pallidum polysaccharides through electrostatic interactions, calcium ion (Ca2+) crosslinking, and lyophilization. Alginate/chitosan (AC) sponges with different concentrations of Sargassum pallidum polysaccharides were obtained and termed AC, ACS-1%, ACS-2.5%, and ACS-5%. ACS-1% and ACS-2.5% sponges exhibited uniform porosity, high water vapor transmission rate, high water absorption, as well as good hemostatic and antibacterial abilities. ACS-2.5% sponges facilitated wound closure and promoted angiogenesis and re-epithelialization in the dermis. These data suggest that ACS sponges containing a certain amount of Sargassum pallidum polysaccharides could be employed for treatment of full-thickness skin wounds.

Sodium Alginate/Chitosan Scaffolds for Cardiac Tissue Engineering: The Influence of Its Three-Dimensional Material Preparation and the Use of Gold Nanoparticles

Natural biopolymer scaffolds and conductive nanomaterials have been widely used in cardiac tissue engineering; however, there are still challenges in the scaffold fabrication, which include enhancing nutrient delivery, biocompatibility and properties that favor the growth, maturation and functionality of the generated tissue for therapeutic application. In the present work, different scaffolds prepared with sodium alginate and chitosan (alginate/chitosan) were fabricated with and without the addition of metal nanoparticles and how their fabrication affects cardiomyocyte growth was evaluated. The scaffolds (hydrogels) were dried by freeze drying using calcium gluconate as a crosslinking agent, and two types of metal nanoparticles were incorporated, gold (AuNp) and gold plus sodium alginate (AuNp+Alg). A physicochemical characterization of the scaffolds was carried out by swelling, degradation, permeability and infrared spectroscopy studies. The results show that the scaffolds obtained were highly porous (>90%) and hydrophilic, with swelling percentages of around 3000% and permeability of the order of 1 × 10−8 m2. In addition, the scaffolds proposed favored adhesion and spheroid formation, with cardiac markers expression such as tropomyosin, troponin I and cardiac myosin. The incorporation of AuNp+Alg increased cardiac protein expression and cell proliferation, thus demonstrating their potential use in cardiac tissue engineering.

Antibacterial biomaterials for skin wound dressing

Bacterial infection and the ever-increasing bacterial resistance have imposed severe threat to human health. And bacterial contamination could significantly menace the wound healing process. Considering the sophisticated wound healing process, novel strategies for skin tissue engineering are focused on the integration of bioactive ingredients, antibacterial agents included, into biomaterials with different morphologies to improve cell behaviors and promote wound healing. However, a comprehensive review on anti-bacterial wound dressing to enhance wound healing has not been reported. In this review, various antibacterial biomaterials as wound dressings will be discussed. Different kinds of antibacterial agents, including antibiotics, nanoparticles (metal and metallic oxides, light-induced antibacterial agents), cationic organic agents, and others, and their recent advances are summarized. Biomaterial selection and fabrication of biomaterials with different structures and forms, including films, hydrogel, electrospun nanofibers, sponge, foam and three-dimension (3D) printed scaffold for skin regeneration, are elaborated discussed. Current challenges and the future perspectives are presented in this multidisciplinary field. We envision that this review will provide a general insight to the elegant design and further refinement of wound dressing.

Perspective on the application of medicinal plants and natural products in wound healing: A mechanistic review

Wound is defined as any injury to the body such as damage to the epidermis of the skin and disturbance to its normal anatomy and function. Since ancient times, the importance of wound healing has been recognized, and many efforts have been made to develop novel wound dressings made of the best material for rapid and effective wound healing. Medicinal plants play a great role in the wound healing process. In recent decades, many studies have focused on the development of novel wound dressings that incorporate medicinal plant extracts or their purified active compounds, which are potential alternatives to conventional wound dressings. Several studies have also investigated the mechanism of action of various herbal medicines in wound healing process. This paper attempts to highlight and review the mechanistic perspective of wound healing mediated by plant-based natural products. The findings showed that herbal medicines act through multiple mechanisms and are involved in various stages of wound healing. Some herbal medicines increase the expression of vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) which play important role in stimulation of re-epithelialization, angiogenesis, formation of granulation tissue, and collagen fiber deposition. Some other wound dressing containing herbal medicines act as inhibitor of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) protein expression thereby inducing antioxidant and anti-inflammatory properties in various phases of the wound healing process. Besides the growing public interest in traditional and alternative medicine, the use of herbal medicine and natural products for wound healing has many advantages over conventional medicines, including greater effectiveness due to diverse mechanisms of action, antibacterial activity, and safety in long-term wound dressing usage.

Studies on novel chitosan/alginate and chitosan/bentonite flexible films incorporated with ZnO nano particles for accelerating dermal burn healing: In vivo and in vitro evaluation

This research work was performed to prepare chitosan-alginate-gelatin and chitosan-bentonite-gelatin films in different mass ratios incorporated with nano particles of Zinc Oxide, which were achieved through the method of green synthesis from Nettle leaf extract. The films were prepared and characterized based on their physicochemical properties, such as water absorption and porosity and surface morphology. Bentonite containing films illustrate more flexibility than alginate ones while the chitosan/bentonite composite films have a maximum water absorption capacity of about 170%. The antibacterial activity of the films was investigated against Staphylococcus aureus and Pseudomonas aeruginosa bacteria and it presents good inhibitory activities against the tested bacteria as compared to the control sample. Furthermore, vivo animal tests were performed to confirm the applicability of the prepared films as a healing material for burned skin. Skin appendages, such as hair follicles and sebaceous gland in the dermis, were detected in normal structures by applying both of the composites to damaged skin. In the control sample (gauze), no re-epithelialized area was observed, except in close proximity of the wound border. The results show that due to its full coverage of the wounds with new epithelium and hair follicles, bentonite-containing composites are more preferred.

Production of wheat germ oil containing multilayer hydrogel dressing

A composite wound dressing has been developed by combining different layers consisting of polymers and textiles. Wheat germ oil (WGO) loaded hydrogels have successfully formed on textile nonwovens by cross-linking sodium alginate (SA) with poly(ethylene glycol) diglycidyl ether (PEGDGE). Following freeze-drying, textile-hydrogel composites have been examined according to their physical properties, pH, fluid handling capacity, water vapour permeability, morphology, chemical structure, and cytotoxicity. Hydrogels containing WGO swelled less than pristine hydrogels. Samples with 1% WGO and no WGO showed swelling of 5.9 and 10.5 g/g after 8 h. WGO inclusion resulted in reduced, but more stable fluid handling properties, with more uniform pore distribution (100-200 μm). Moreover, the proliferation of NIH/3T3 cells significantly improved with 1% WGO contained hydrogels. Also, commercial self-adhesive dressings that secure the hydrogels to the wound area were investigated regarding transfer properties. The proposed product demonstrated 8.05 cm³/cm²/s and 541.37 g/m²/day air and water vapour permeability.

Alginate and alginate composites for biomedical applications

Alginate is an edible heteropolysaccharide that abundantly available in the brown seaweed and the capsule of bacteria such as Azotobacter sp. and Pseudomonas sp. Owing to alginate gel forming capability, it is widely used in food, textile and paper industries; and to a lesser extent in biomedical applications as biomaterial to promote wound healing and tissue regeneration. This is evident from the rising use of alginate-based dressing for heavily exuding wound and their mass availability in the market nowadays. However, alginate also has limitation. When in contact with physiological environment, alginate could gelate into softer structure, consequently limits its potential in the soft tissue regeneration and becomes inappropriate for the usage related to load bearing body parts. To cater this problem, wide range of materials have been added to alginate structure, producing sturdy composite materials. For instance, the incorporation of adhesive peptide and natural polymer or synthetic polymer to alginate moieties creates an improved composite material, which not only possesses better mechanical properties compared to native alginate, but also grants additional healing capability and promote better tissue regeneration. In addition, drug release kinetic and cell viability can be further improved when alginate composite is used as encapsulating agent. In this review, preparation of alginate and alginate composite in various forms (fibre, bead, hydrogel, and 3D-printed matrices) used for biomedical application is described first, followed by the discussion of latest trend related to alginate composite utilization in wound dressing, drug delivery, and tissue engineering applications.

The biological synthesis of gold/perlite nanocomposite using Urtica dioica extract and its chitosan-capped derivative for healing wounds infected with methicillin-resistant Staphylococcus aureus

The preparation of ointments from natural compounds is essential for accelerating infected wounds. This study investigated the effects of topical uses of gold nanoparticles (Au)/perlite (Au/Perl) nanocomposites (NCs) by the help of Urtica dioica extract and its chitosan-capped derivative (Chit) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing in a mouse model. Furthermore, Au/Perl/Chit nanocomposite was prepared using protonated chitosan solution. The physicochemical properties of the as-synthesized nanocomposites were also investigated. The effects of Au/Perl/Chit NC were assessed by antibacterial, histopathological parameters as well as molecular evaluations. Then, they were compared with synthetic agent of mupirocin. The results revealed that Au/Perl NC was mesoporous and spherical in a range of 13-15 nm. Topical administration of Au/Perl/Chit ointment accelerated wound healing by reducing bacteria colonization and wound rate enhancing collagen biosynthesis and re-epithelialization, the expressions of IL-10, PI3K, AKT, bFGF, and COL1A genes, which is in agreement with the obtained results for mupirocin. In conclusion, the results strongly demonstrated that administration of ointments prepared from Au/Perl and Au/Perl/Chit nanocomposites stimulates MRSA-infected wound healing by decreasing the length of healing time and regulating PI3K/AKT/bFGF signaling pathway and is a promising candidate in stimulating MRSA-infected wound regeneration.

Nanocomposite sponges for enhancing intestinal residence time following oral administration

In this work, nanocomposites that combine mucopenetrating and mucoadhesive properties in a single system are proposed as innovative strategy to increase drug residence time in the intestine following oral administration. To this aim, novel mucoadhesive chitosan (CH) sponges loaded with mucopenetrating nanoemulsions (NE) were developed via freeze-casting technique. The NE mucopenetration ability was determined studying the surface affinity and thermodynamic binding of the nanosystem with mucins. The ability of nanoparticles to penetrate across a preformed mucins layer was validated by 3D-time laps Confocal Laser Scanning Microscopy imaging. Microscopy observations (Scanning Electron Microscopy and Optical Microscopy) showed that NE participated in the structure of the sponge affecting its stability and in vitro release kinetics. When incubated with HCT 116 and Caco-2 cell lines, the NE proved to be cytocompatible over a wide concentration range. Finally, the in vivo biodistribution of the nanocomposite was evaluated after oral gavage in healthy mice. The intestinal retention of NE was highly enhanced when loaded in the sponge compared to the NE suspension. Overall, our results demonstrated that the developed nanocomposite sponge is a promising system for sustained drug intestinal delivery.

Toward Regulatory Effects of Curcumin on Transforming Growth Factor-Beta Across Different Diseases: A Review

Immune response, proliferation, migration and angiogenesis are juts a few of cellular events that are regulated by transforming growth factor-β (TGF-β) in cells. A number of studies have documented that TGF-β undergoes abnormal expression in different diseases, e.g., diabetes, cancer, fibrosis, asthma, arthritis, among others. This has led to great fascination into this signaling pathway and developing agents with modulatory impact on TGF-β. Curcumin, a natural-based compound, is obtained from rhizome and roots of turmeric plant. It has a number of pharmacological activities including antioxidant, anti-inflammatory, anti-tumor, anti-diabetes and so on. Noteworthy, it has been demonstrated that curcumin affects different molecular signaling pathways such as Wnt/β-catenin, Nrf2, AMPK, mitogen-activated protein kinase and so on. In the present review, we evaluate the potential of curcumin in regulation of TGF-β signaling pathway to corelate it with therapeutic impacts of curcumin. By modulation of TGF-β (both upregulation and down-regulation), curcumin ameliorates fibrosis, neurological disorders, liver disease, diabetes and asthma. Besides, curcumin targets TGF-β signaling pathway which is capable of suppressing proliferation of tumor cells and invading cancer cells.

Development of a Multifunctional Bioerodible Nanocomposite Containing Metronidazole and Curcumin to Apply on L-PRF Clot to Promote Tissue Regeneration in Dentistry

Teeth extractions are often followed by alveolar bone reabsorption, although an adequate level of bone is required for reliable rehabilitations by dental implants. Leukocyte and platelet-rich fibrin (L-PRF) has been widely applied in regenerative procedures and with antibiotic and antioxidant agents could play an essential role in hard and soft tissue healing. In this work, a nanocomposite (Sponge-C-MTR) consisting of a hyaluronate-based sponge loaded with metronidazole (MTR) and nanostructured lipid carriers containing curcumin (CUR-NLC) was designed to be wrapped in the L-PRF™ membrane in the post-extraction sockets and characterized. CUR-NLCs, obtained by homogenization followed by high-frequency sonication of the lipid mixture, showed loading capacity (5% w/w), drug recovery (95% w/w), spherical shape with an average particle size of 112.0 nm, and Zeta potential of -24 mV. Sponge-C-MTR was obtained by entrapping CUR-NLC in a hydrophilic matrix by a freeze-drying process, and physico-chemical and cytocompatibility properties were evaluated. Moreover, the aptitude of CUR and MTR to the penetrate and/or permeate both L-PRF™ and porcine buccal tissue was assessed, highlighting MTR penetration and CUR accumulation promoted by the system. The results positively support the action of nanocomposite in dental tissues regeneration when applied together with the L-PRF™.

Obstacles against the Marketing of Curcumin as a Drug

Among the extensive public and scientific interest in the use of phytochemicals to prevent or treat human diseases in recent years, natural compounds have been highly investigated to elucidate their therapeutic effect on chronic human diseases including cancer, cardiovascular disease, and neurodegenerative disease. Curcumin, an active principle of the perennial herb Curcuma longa, has attracted an increasing research interest over the last half-century due to its diversity of molecular targets, including transcription factors, enzymes, protein kinases, growth factors, inflammatory cytokines, receptors, and it's interesting pharmacological activities. Despite that, the clinical effectiveness of the native curcumin is weak, owing to its low bioavailability and rapid metabolism. Preclinical data obtained from animal models and phase I clinical studies done in human volunteers confirmed a small amount of intestinal absorption, hepatic first pass effect, and some degree of intestinal metabolism, might explain its poor systemic availability when it is given via the oral route. During the last decade, researchers have attempted with new pharmaceutical methods such as nanoparticles, liposomes, micelles, solid dispersions, emulsions, and microspheres to improve the bioavailability of curcumin. As a result, a significant number of bioavailable curcumin-based formulations were introduced with a varying range of enhanced bioavailability. This manuscript critically reviews the available scientific evidence on the basic and clinical effects and molecular targets of curcumin. We also discuss its pharmacokinetic and problems for marketing curcumin as a drug.

Evidence-Based Perioperative Nutrition Recommendations: Optimizing Results and Minimizing Risks

Plastic surgery patients span the nutritional spectrum from generally healthy, nutritionally competent patients to inherently catabolic, nutritionally deficient, and chronic wound patients. Therefore, plastic and reconstructive surgery affords the opportunity to investigate the impact of nutrition across a heterogeneous patient population following a wide variety of procedures. Although patients may be nutritionally deficient in certain vitamins warranting perioperative repletion, other supplements have the potential to benefit all patients, regardless of nutritional status. Despite these putative benefits, there is a dearth of information regarding nutritional optimization, with the limited, available literature focusing mostly on herbal supplements and their potential side effects. A significant barrier to supplement use is the lack of education and available supporting information regarding the indications, contraindications, and physiology of these adjuncts. The goal of this article is to provide a comprehensive, evidence-based review of available nutritional supplements that can be considered for the plastic surgery patient in the perioperative period to optimize surgical outcomes while minimizing risk. Prospective, well-designed studies using validated, high-quality supplements will be critical in determining the significance that perioperative supplementation can have for surgical outcomes. Until well-done prospective studies are performed, the supplement, dose, and duration should be determined on an individual, patient-per-patient basis at the discretion of the operating surgeon.

Polydopamine coating of uncrosslinked chitosan as an acellular scaffold for full thickness skin grafts

There is an unmet need for skin grafting materials that are readily available for large area wounds, due to complex, lengthy and costly manufacturing processes that are not compatible with this type of wounds. Here we developed an acellular skin graft material based on surface coating of uncrosslinked porous (UCLP) chitosan. UCLP chitosan membranes had mechanical properties in ranges suitable for skin grafting. Polydopamine (PDA) coating improved hydrophilicity and resulted in a significant increase in attachment and metabolic activity of mammalian cells in vitro. PDA coating also decreased the attachment of pseudomonas aeruginosa - a common bacteria infecting skin wounds. Finally, the PDA-coated membranes were implanted in full thickness surgical wounds in a rodent model and resulted in complete would closure in 5 days. The current study suggests that PDA-coated UCLP chitosan membranes could be a simple and effective strategy for the development of grafting materials for large area wounds.

O-Carboxymethyl chitosan-based pH-responsive amphiphilic chitosan derivatives: Characterization, aggregation behavior, and application

Chitosan has attracted much attention in drug delivery, however, carboxymethyl chitosan (CMC)-based self-aggregated nanocarriers are seldom reported. In this paper, two kinds of CMC-based pH-responsive amphiphilic chitosan derivatives, N-2-hydroxylpropyl-3-butyl ether-O-carboxymethyl chitosan (HBCC) and N-2-hydroxylpropyl-3-(2-ethylhexyl glycidyl ether)-O-carboxymethyl chitosan (H2ECC), have been synthesized by the homogeneous reaction. The molecular structures were characterized by FTIR, ¹H NMR and ¹³C NMR. The optimum reaction condition was obtained based on the data of ¹H NMR spectrum: reaction time of 4 h, reaction temperature of 80 °C and n_epoxyn_-NH2 of 3/1, respectively. The XRD patterns showed the crystallinity of HBCC and H2ECC decreased due to the introduction of hydrophobic segments. The thermostability of HBCC and H2ECC was improved for the formation of heat-resistant stereo-complexed structures. The intermolecular hydrophobic interaction hindered the intermolecular mobility by increasing glass transition temperature of ca. 10 °C. Both HBCC and H2ECC have very low critical aggregation concentrations (HBCC: 0.66-1.56 g/L, H2ECC: 0.57-1.07 g/L) and moderate aggregate particle size, which is advantageous for utilization as a drug carrier. The curcumin loaded HBCC and H2ECC aggregates showed nontoxicity, meanwhile, HBCC and H2ECC showed good antibacterial activity against Staphylococcus aureus and Escherichia coli. As a result of these two favorable properties, HBCC and H2ECC could be used as curcumin nanocarriers as well as antibacterial agents.

A hydrogen sulfide-releasing alginate dressing for effective wound healing

For wounds with heavy exudate levels, a dressing that can help to absorb wound exudate and improve the wound healing process is highly desired. Hydrogen sulfide (H₂S) has been recognized as an important gasotransmitter that can improve angiogenesis which is crucial for wound healing. In this study, a functional sodium alginate (SA) dressing with H₂S-releasing property (SA/JK-1) was fabricated by incorporating JK-1 molecule, a pH-dependent H₂S donor, into SA sponge. The resultant SA/JK-1 sponge provided a moist and protective healing environment and was capable of releasing H₂S consistently under acidic pH condition by absorbing exudate at the wound interface. The H₂S release of JK-1 donor was prolonged by the SA sponge compared with JK-1 in solution. Cell study in vitro indicated that SA/JK-1 not only exhibited good cyto-compatibility, but also improved fibroblast proliferation and migration. In addition, the effects of the SA/JK-1 dressing on wound healing was evaluated using an in vivo full thickness dermal defect model, which revealed that SA/JK-1 can significantly improve wound healing process with enhanced granulation tissue formation, re-epithelialization, collagen deposition and angiogenesis, due to the H₂S released from JK-1. Taken together, our results showed that SA dressing doped with H₂S donor could potentially serves as an effective wound healing strategy. STATEMENT OF SIGNIFICANCE: The gasotransmitter H₂S has been proven to improve the wound healing process in nanofibrous dressing due to its biological functions on angiogenesis. However, for non-healing wounds with heavy exudates, a wound dressing that can absorb wound exudates and controlled gasotransmitter release to improve the wound healing process is still in urgent need. Here we fabricated a sodium alginate (SA) sponge incorporated with H₂S donor JK-1 (SA/JK-1), which showed strong water uptake capability, and released H₂S under acidic condition. The SA/JK-1 sponge exhibited biocompatibility to fibroblasts and promoted cell migration in vitro, and exhibited obviously positive influence on wound healing in vivo. This H₂S donor doped alginate wound dressing represents a promising strategy for treatment of non-healing wound.

A human epidermal growth factor-curcumin bandage bioconjugate loaded with mesenchymal stem cell for in vivo diabetic wound healing

Bone-marrow-derived mesenchymal stem cells (MSCs) are of growing interest for the treatment of diabetic wound healing. However, they are often associated with poor proliferation and viability at the wounded site. Here, it is reported the use of human epidermal growth factor -curcumin bandage bioconjugate (EGF-Cur B) loaded with MSCs (MSCs-EGF-Cur B) at the wounded site for diabetic wound healing. Conjugation efficiency of EGF was determined by FTIR and XPS, surface morphology was analyzed by SEM and AFM and hydrophilicity by contact angle. Chemical integrity of curcumin with the polymeric matrix was studied by FTIR and, antiinflamatory and biocompatibility of EGF-Cur B were determined by TNF α ELISA and MTT study respectively. The culture of MSCs over EGF-Cur B enhanced MSC viability and expression of transcription factors associated with the maintenance of pluripotency and self-renewal (OCT¾, SOX2, and Nanog) as compared to MSCs grown in standard conditions. Its therapeutic effect was examined on diabetic full-thickness excisional wound model in terms of size and histological examination. Synergetic combinational approach especially when treated with MSCs-EGF-Cur B significantly enhanced wound closure by increasing granulation tissue formation, collagen deposition, and angiogenesis as compared to other groups. In conclusion, biocompatible therapeutic MSCs-EGF-Cur B might have great application for diabetic wound healing in the near future.

Fabrication of Nanofibrous/Xerogel Layer-by-Layer Biocomposite Scaffolds for Skin Tissue Regeneration: In Vitro Study

Skin burn wounds are a crucial issue that could reduce life quality. Although numerous effective skin products have invaded the biomedical market, most of them still demonstrate some limitations regarding their porosity, swelling and degradation behaviors, antibacterial properties, and cytotoxicity. Thus, the aim of this study is to fabricate novel trilayered asymmetric porous scaffolds that can mimic the natural skin layers. In particular, the fabricated scaffold constitutes an upper electrospun chitosan-poly(vinyl alcohol) layer and a lower xerogel layer, which is made of effective skin extracellular matrix components. Both layers are fixed together using fibrin glue as a middle layer. The results of this study revealed promising scaffold swelling capability suitable for absorbing wound exudates, followed by a constant degradable weight over time, which is appropriate for a burn wound environment. Scanning electron microscopy images revealed an average pore diameter in the range of 138.39-170.18 nm for the cross-linked electrospun mats and an average pore size of 2.29-30.62 μm for the fabricated xerogel layers. This further provided an optimum environment for fibroblast migration and proliferation. The electrospun nanofibrous layer was examined for its antibacterial properties and showed expressive complete bacterial inhibition against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains (log reduction = 3 and 2.70, respectively). Next, mouse embryonic fibroblast cytotoxicity and migration rate were investigated against the developed asymmetrical composite to assess its biocompatibility. Tissue culture experiments demonstrated significant cell proliferation and migration in the presence of the constructed scaffold (P < 0.0001). A complete wound closure was observed in vitro in the presence of the three scaffold asymmetrical layers against the mouse embryonic fibroblast. The results of this study proved superior biological characteristics of the innovative asymmetrical composite that could further replace the burned or damaged skin layers with promising potential for clinical applications.

Reinforcement of Polycaprolactone/Chitosan with Nanoclay and Controlled Release of Curcumin for Wound Dressing

A novel clay-reinforced polycaprolactone/chitosan/curcumin (PCl/CS/Clay/Cur) composite film was fabricated in this study. The prepared Cur-loading composite films were characterized with attenuated total reflection Fourier transformed infrared spectroscopy, scanning electron microscopy, atomic force microscopy, water contact angle, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction, and the results showed good dispersion of clay in the composite films. The addition of nanoclay was found to significantly increase the tensile strength. Also, the clay-enhanced drug-loading films exhibited better controlled-release profiles of Cur than those membranes without clay. Skin disinfection test demonstrated that the curcumin-loaded film could protect wound from bacterial infection. Cytotoxicity analysis proved the good biocompatibility of the composite films. The clay-enhanced Cur-loading films might be promising candidates for wound care.

A novel curcumin-loaded composite dressing facilitates wound healing due to its natural antioxidant effect

Purpose

To prepare a novel wound dressing to facilitate cutaneous wound healing.

Methods

Curcumin (Cur) was added to the ring-shaped β-cyclodextrin (CD) to form a β-CD–Cur inclusion complex (CD-Cur). CD-Cur was then integrated into a composite chitosan–alginate (CA) mix. Finally, CA-CD-Cur was generated with a freeze-drying technique. Water-uptake capacity, degradation rate, and drug-release kinetics of the newly formed dressing were investigated in vitro. In animal studies, cutaneous wounds in rats were created, treated with CA-CD-Cur, then compared to CA-Cur, CA, and gauze.

Results

CA-CD-Cur–treated wounds showed accelerated closure rates, improved histopathological results, and lower SOD, lipid peroxidation, pI3K, and pAktkt levels than other groups. On the contrary, catalase, IκBα, and TGFβ₁ levels were higher than others.

Conclusion

CA-CD-Cur may facilitate cutaneous wound dressing that facilitate wound healing.

Potential of Curcumin in Skin Disorders

Curcumin is a compound isolated from turmeric, a plant known for its medicinal use. Recently, there is a growing interest in the medical community in identifying novel, low-cost, safe molecules that may be used in the treatment of inflammatory and neoplastic diseases. An increasing amount of evidence suggests that curcumin may represent an effective agent in the treatment of several skin conditions. We examined the most relevant in vitro and in vivo studies published to date regarding the use of curcumin in inflammatory, neoplastic, and infectious skin diseases, providing information on its bioavailability and safety profile. Moreover, we performed a computational analysis about curcumin's interaction towards the major enzymatic targets identified in the literature. Our results suggest that curcumin may represent a low-cost, well-tolerated, effective agent in the treatment of skin diseases. However, bypass of limitations of its in vivo use (low oral bioavailability, metabolism) is essential in order to conduct larger clinical trials that could confirm these observations. The possible use of curcumin in combination with traditional drugs and the formulations of novel delivery systems represent a very promising field for future applicative research.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Thaw-Induced Gelation of Alginate Hydrogels for Versatile Delivery of Therapeutics

Alginate hydrogels have been extensively used and successfully validated as delivery vehicles of bioactive factors in many tissue engineering applications. This work describes and characterizes a singular alternative method to create alginate hydrogels designated as thaw-induced gelation (TIG). The TIG method involves gelation through the time-dependent release of the polymer or crosslinker by melting into solution. Alginate TIG hydrogels were validated for spatial-temporal control delivery of different cargos including albumin, dextran, and doxorubicin. Chitosan was incorporated into TIG hydrogels to investigate the electrostatic interactions between alginate and the tested cargos. Interestingly, while 90% of doxorubicin was released after 8 h from hydrogels formed with frozen calcium, hydrogels formulated from frozen alginate took 72 h. In addition, the storage modulus of TIG hydrogels prepared from frozen alginate was double that of a hydrogel formed without freezing alginate. Therefore, the utility of TIG strategies are particularly promising for the delivery of therapeutic cargos smaller than the mesh size of the alginate hydrogel, as it enables controlled release of these cargos without any further chemical modifications of the hydrogels. These TIG alginate hydrogels with tunable mechanical properties and control over the delivery of smaller cargos could be useful in many tissue engineering applications.

Nutrition and Wound Healing: An Overview Focusing on the Beneficial Effects of Curcumin

Wound healing implicates several biological and molecular events, such as coagulation, inflammation, migration-proliferation, and remodeling. Here, we provide an overview of the effects of malnutrition and specific nutrients on this process, focusing on the beneficial effects of curcumin. We have summarized that protein loss may negatively affect the whole immune process, while adequate intake of carbohydrates is necessary for fibroblast migration during the proliferative phase. Beyond micronutrients, arginine and glutamine, vitamin A, B, C, and D, zinc, and iron are essential for inflammatory process and synthesis of collagen. Notably, anti-inflammatory and antioxidant properties of curcumin might reduce the expression of tumor necrosis factor alpha (TNF-α) and interleukin-1 (IL-1) and restore the imbalance between reactive oxygen species (ROS) production and antioxidant activity. Since curcumin induces apoptosis of inflammatory cells during the early phase of wound healing, it could also accelerate the healing process by shortening the inflammatory phase. Moreover, curcumin might facilitate collagen synthesis, fibroblasts migration, and differentiation. Although curcumin could be considered as a wound healing agent, especially if topically administered, further research in wound patients is recommended to achieve appropriate nutritional approaches for wound management.

Curcumin nanoparticles incorporated collagen-chitosan scaffold promotes cutaneous wound healing through regulation of TGF-β1/Smad7 gene expression

Wound healing is a tissue regeneration process which is regulated by a complex interaction of multiple growth factors, primarily transforming growth factor-β1 (TGF-β1). The natural antagonist of transforming growth factor-β (TGF-β) signaling is Smad7. It has been shown that curcumin (an antioxidant) and some biocompatible polymers like collagen and chitosan enhance cutaneous wound healing. In this study, three scaffolds made with curcumin-nanoparticles (CNs) and using collagen and chitosan with various ratios of collagen and chitosan were used for evaluation of wound healing activity on full thickness punch wound model using male Wistar rats. The wound healing in terms of histology and morphology was assessed at different time points post-wounding and the expression pattern of TGF-β1 and Smad7 was studied. CNs incorporated collagen-chitosan scaffolds significantly accelerated the healing of the wounds, as revealed by a significant change in the wound area, the epidermal thickness, the density of granulation tissue, the number of new vessels and a higher collagen content compared to the control group. However, blank collagen-chitosan scaffolds did not cause any significant change in the above parameters, except for epidermal thickness compared to the control group. Incorporation of CNs into collagen-chitosan scaffold changed expression of TGF-β1 and Smad7 mRNAs in the healing wounds compared to the control group. Indeed, blank collagen-chitosan scaffold did not cause any significant up-regulation either in TGF-β1 mRNA expression or in Smad7 mRNA expression (except for day 3 post-wounding), compared to the control group. This study indicates that topical application of CNs-incorporated collagen-chitosan scaffold promotes wound healing via a regulatory effect on the expression of TGF-β1 and Smad7 mRNA in the cutaneous wound-healing model.

Development of polyurethane foam dressing containing silver and asiaticoside for healing of dermal wound

Polyurethane foam dressings for dermal wounds were formulated with natural polyols in order to improve the foam characteristics and the release of 2 active agents, silver and asiaticoside (AS) as an antimicrobial agent and an herbal wound healing agent, respectively. The foam was instantly formed by interaction of polyols and diisocyanate. Hydroxypropyl methylcellulose, chitosan and sodium alginate were individually mixed with the main polyols, polypropylene glycol, in the formulation while the active components were impregnated into the obtained foam dressing sheets. Although the type and amount of the natural polyols slightly affected the pore size, water sorption-desorption profile and compression strength of the obtained foam sheets, a prominent effect was found in the release of both active components. Among natural polyols formulations, foam sheets with alginate showed the highest silver and AS release. Non-cytotoxicity of these foam sheets to human fibroblast cells was confirmed. Antimicrobial testing on four bacteria strains showed that 1 mg/cm2 silver in formulations with 6% of natural polyols and without natural polyols had sufficient content of the silver release with comparable inhibition zone and significantly larger zone than other formulations. In pig study, the foam dressing with 6% alginate, 1 mg/cm2 silver and 5% AS could improve wound healing in both the percentage of the wound closure and histological parameters of the dermal wound without any dermatologic reactions. In conclusion, this innovative foam dressing had potential to be a good candidate for wound treatment.

A simple strategy to enhance the in vivo wound-healing activity of curcumin in the form of self-assembled nanoparticle complex of curcumin and oligochitosan

While the wound healing activity of curcumin (CUR) has been well-established, its clinical effectiveness remains limited due to the inherently low aqueous CUR solubility, resulting in suboptimal CUR exposure in the wound sites. Previously, we developed high-payload amorphous nanoparticle complex (or nanoplex) of CUR and chitosan (CHI) capable of CUR solubility enhancement by drug-polyelectrolyte complexation. The CUR-CHI nanoplex, however, exhibited poor colloidal stability due to its strong agglomeration tendency. Herein we hypothesized that the colloidal stability could be improved by replacing CHI with its oligomers (OCHI) owed to the better charge distribution in OCHI. The effects of key parameters in drug-polyelectrolyte complexation (i.e. pH, salt inclusion, CUR concentration, and OCHI/CUR charge ratio) on the physical characteristics and preparation efficiency of the CUR-OCHI nanoplex produced were investigated. The in vivo wound healing efficacy of the CUR-OCHI nanoplex and its cytotoxicity towards human keratinocytes cells were examined. The results showed that CUR-OCHI nanoplex exhibited prolonged colloidal stability (72 h versus <24 h for the CUR-CHI nanoplex). At the optimal condition, the CUR-OCHI nanoplex (without ultrasonication) exhibited size, zeta potential, and CUR payload of ≈140 nm, 20 mV, and 78% (w/w), respectively. The nanoplex preparation was simple yet robust at nearly 100% CUR utilization rate. The CUR-OCHI nanoplex exhibited superior wound healing efficacy to the native CUR with wound closure of >90% after 7 days versus 9 days for the native CUR resulting in smaller scars, attributed to its generation of high CUR concentration in the wound sites.