Topical formulations and wound healing applications of chitosan

Molybdoenzymes-emulating bio-heterojunction hydrogel with rapid disinfection and macrophage reprogramming for wound regeneration

Developing hydrogel dressings with the capabilities to accommodate irregular wounds and provide a cascade disinfective-regenerative microenvironment for wound repair is of great importance to combating pathogenic bacteria-infected wounds but remains an ongoing challenge. To address the conundrum, we devise a molybdoenzymes-emulating bio-heterojunction (M-bioHJ) doped double network (DN) hydrogel dressing for bacterial-infected wound healing. The near-infrared (NIR) photothermal effect of the M-bioHJ facilitates the exchange of multiple dynamic crosslinking sites in the hydrogel, endowing the hydrogel with photo-remote reprocessing capabilities to completely accommodate the encountered irregular wounds and ultimately accomplish the admirable therapeutic effect. Meanwhile, the introduced M-bioHJ shows NIR light-enhanced photodynamic activity to induce a massive engendering of reactive oxygen species (ROS), allowing rapid sterilization without reliance on exogenous hydrogen peroxide. Furthermore, the Mo ions released from the M-bioHJ-encapsulated hydrogel can play a crucial role in reprogramming the macrophage phenotype and determining tissue regeneration. Both in vitro and in vivo evidences authenticate the accelerated healing potential of infected wounds through the synergistic effects of photo-reprocessing, disinfection, and macrophage-reprogramming facilitated by the hydrogel. These findings highlight the promising application prospects of such neoteric M-bioHJ-encapsulated hydrogel dressings for wound disinfection and tissue regeneration.

Influence of alkali treatment and ultrasonication on the bioactivities and rheological properties of sulfated polysaccharides

The rheological, antioxidant and anticoagulant properties of 17 different structurally uniform and hybrid sulfated polysaccharides are presented in this study. Alkali treatment was used to modify carrageenan precursors, while ultrasonication was employed to partially depolymerize polysaccharide chains. Native and modified sulfated polysaccharides with well-resolved molecular structures were characterized by size exclusion chromatography and dynamic rheometry methods. Extensive ultrasonication (1-64 min) reduced the molecular weights of the samples from approximately 384-1156 kDa to 47-95 kDa. Their rheological properties showed strong dependence on molecular weight, with gelling ability decreasing in the order: furcellaran, kappa carrageenan > iota carrageenan, funoran > lambda carrageenan > theta carrageenan, sulfated chitosan. The anticoagulant activity, measured via aPTT assay, followed the order: lambda carrageenan > iota carrageenan, kappa/iota carrageenan, carrageenan mixture, sulfated chitosan > theta carrageenan > kappa carrageenan, funoran. Among the antioxidant properties determined using Folin-Ciocalteu, DPPH, ABTS, OH radical, and FRAP assays, OH radical scavenging activity was particularly noteworthy, being inherent to all polysaccharides and displaying a correlation with molecular weight. These results validate the interdependence of alkali treatment and the molecular weights of both natural and chemically sulfated polysaccharides in influencing their respective anticoagulant and antioxidant activities measured using in-vitro assays.

Comparative evaluation of chitligsan nanosuspension gel and spray for enhancing full-thickness wound healing in a rat model

Introduction: This study explores the wound healing potential of Chitligsan (CHG), a novel formulation derived from the enzymatic and fossil-based components of Sahara soil, in nanosuspension-based gel and spray forms. Using a full-thickness wound model in Wistar rats, CHG's efficacy was compared with saline (control) and terramycin treatments.

Methods: A total of 48 rats were divided into four groups: Control (saline), Spray (CHG spray), Gel (CHG gel), and Terramycin pomad. Wound areas were measured at days 3, 7, 14, and 21.

Results: By day 21, CHG spray reduced wound size to 0.08 ± 0.01 cm2, while the gel achieved 0.09 ± 0.01 cm2, outperforming both control (0.34 ± 0.02 cm2) and terramycin (0.14 ± 0.05 cm2, p < 0.05). Histopathological analysis demonstrated superior epithelial regeneration, dense collagenization, and minimal inflammation in CHG-treated groups compared to others. The nanoscale size of CHG particles (89.6 ± 0.26 nm) and their stable zeta potential (-26.1 ± 1.5 mV) contributed to enhanced bioavailability and wound healing efficiency. Morphological and FTIR analyses confirmed the stability and compatibility of the nanosuspension.

Conclusions: This study highlights CHG's potential as a biocompatible and effective wound care solution, offering significant advantages in granulation tissue formation and keratinization compared to conventional treatments.

Dextran-block-poly(benzyl glutamate) block copolymers via aqueous polymerization-induced self-assembly

Combining polysaccharides with polypeptides enables growth of diverse nanostructures with minimal toxicity, low immune response, and potential biodegradability. However, examples of nanostructures combining polysaccharides with polypeptides are limited due to synthetic difficulties and related issues of solubility, purification, and characterization, with previous reports of polysaccharide-block-polypeptide block copolymers requiring methods such as polymer-polymer coupling and post-polymerization modifications paired with difficult purification steps. Here, we synthesized dextran-block-poly(benzyl glutamate) block copolymers in water via polymerization-induced self-assembly (PISA) to form nanostructures in situ, studying their morphologies using experimental methods and molecular modeling. Transmission electron microscopy revealed globular but non-spherical nanostructures throughout the PISA process, in contrast to PISA processes using poly(ethylene glycol) (PEG) as the hydrophilic block, which have shown a range of well-defined nanostructures. Coarse-grained molecular dynamics simulations on several homopolymers and block copolymers revealed that dextran chains interacted more strongly with each other compared to PEG, and that water packed less densely around dextran than around PEG. The combined experimental and computational results indicated that while dextran is hydrophilic, its interactions with itself led to the formation of unexpected nanostructures in this dextran-block-polypeptide system, suggesting that these interactions may be exploited to form unique nanostructures compared with other common hydrophilic blocks.

Treatment of Staphylococcus aureus-infected diabetic wounds by melatonin loaded nanocarriers

One of the complication of diabetes mellitus is chronic wounds. The healing of wounds in diabetic patients is retarded by the elevation in the pro-inflammatory cytokines secretion and free radicles accumulation. Wound management in diabetic patients requires preventing bacterial biofilm development. Due to the wound healing activity of chitosan (CS), lecithin (Le) and melatonin (M), the present study aimed to load melatonin on CS/Le NPs and examine their effect on diabetic wounds infected with Staphylococcus aureus. Melatonin loaded chitosan/lecithin nanoparticles (M-CS/Le NPs) were physically characterized and their antioxidant, anti-inflammatory and antimicrobial activities were examined in vitro. Male Sprague Dawley rats included two division (non-diabetic and diabetic) which were further divided in nine groups. Diabetes induction and follow up throughout the experimental period was confirmed by measuring the levels of fructosamine and blood glucose. Full-thickness wounds was induced in both non-diabetic and diabetic animals followed by infection with Staphylococcus aureus according to the experimental design. The wound healing effect of M-CS/Le NPs was evaluated through measurements of the oxidative stress, inflammatory cytokines and apoptotic proteins. Our results showed the anti-microbial, free radical scavenging and hemolysis inhibition effects of M-CS/Le NPs in vitro. Moreover, the preparation of M-CS/Le NPs decreased the dose of used melatonin (when compared to free melatonin). M-CS/Le NPs significantly decreased the wound area percent in treated infected wounds of both non-diabetic and diabetic rats more than free melatonin or unloaded CS/Le NPs. In conclusion, M-CS/Le NPs promoted the wound healing in Staphylococcus aureus-infected wounds in diabetic rats.

Development of self-healing hydrogels to support choroidal endothelial cell transplantation for the treatment of early age related macular degeneration

In retinal diseases such as age-related macular degeneration (AMD) and choroideremia, a key pathophysiologic step is loss of endothelial cells of the choriocapillaris. Repopulation of choroidal vasculature early in the disease process may halt disease progression. Prior studies have shown that injection of donor cells in suspension results in significant cellular efflux and poor cell survival. As such, the goal of this study was to develop a hydrogel system designed to support choroidal endothelial cell transplantation. A library of hydrogels was synthesized using laminin (i.e., LN111, LN121, and LN421), carboxy methyl chitosan, and oxidized dextran via reversible Schiff base chemistry. Each of the developed self-healing hydrogels was readily injectable into the suprachoroidal space, with ideal gelation, mechanical, and degradation properties. While all hydrogels were found to be compatible with choroidal endothelial cell survival in vitro, only LN111 and LN121 gels were well-tolerated in vivo. To determine if hydrogel mediated cell delivery enhances donor cell retention and survival in vivo, iPSC-derived choroidal endothelial cell laden hydrogels were injected into the suprachoroidal space of an immunocompromised choroidal cell injury rat model. Significantly more donor cells were retained and survived in eyes that received cell laden hydrogels versus contralateral hydrogel free controls. Furthermore, donor cells positive for human nuclear antigen were identified in the choroid of hydrogel eyes only. These findings pave the way for future cell replacement studies in large animal models of choroidal cell dropout focused on evaluating functional integration of donor cells within decellularized vascular tubes. STATEMENT OF SIGNIFICANCE: Age related macular degeneration (AMD) is a leading cause of untreatable blindness in the industrial world. A key pathologic step in AMD is loss of the choriocapillaris endothelial cells, which provide vascular support to the overlying retina. Choroidal cell replacement early in disease may prevent retinal cell death and subsequent vision loss. In this study, we present a strategy for repopulating the choriocapillaris using choroidal endothelial cell laden hydrogels. Specifically, we demonstrate the synthesis and characterization of 3 different laminin-based hydrogel systems. LN111 and LN121 hydrogels were found to have excellent biocompatibility both in vitro and in vivo. Hydrogel mediated delivery of iPSC-derived choroidal endothelial cells enhanced donor cell retention and survival, paving the way for functional large animal studies.

Fabrication and Characterizations of Microwave‐Assisted Gelatin Cross‐Linked LBG/Guar Gum–Based Super Porous Hydrogels With Metformin Hydrochloride for Open Incision Wound Healing

The goal of this study was to fabricate gelatin cross‐linked Locust bean gum (LBG)/guar gum–based hydrogels with microwave assistance for diabetic wound healing applications and evaluate it for physicochemical properties. In the last few years, microwave irradiation has gained acceptance as a reliable technique for quickening and streamlining chemically modified reactions. In order to achieve this, metformin‐loaded LBG and guar gum–based hydrogel were formulated employing microwave radiation. Moreover, the microwave‐assisted–based metformin hydrogel are microwave‐assisted reaction sudden increase in temperature may led to distortion of molecules, very vigorous and which may be hazardous, but environmental sustainability and friendly chemistry concepts are supported by microwave irradiation. The optimized formulation (F3) showed significantly improved physicochemical properties, with a swelling capacity of 480.4% ± 2.5%. The results indicate an appropriate duration for adequate drugs diffusion and nutrition exchange. Controlled disintegrate and sustained release of embedded drug molecules from F3 may have an impact on antibacterial activity. The study indicated that microwave‐assisted polymer blend hydrogels had adequately improved physical qualities, making them a promising candidate for improving diabetic wound healing and hastening skin tissue regeneration.

Bioactive compounds in edible insects: Aspects of cultivation, processing and nutrition

The increasing interest in edible insects, driven by projected global population growth and environmental concerns, has led to the exploration of their potential in the food sector. Edible insects are abundant in macronutrients, such as proteins, lipids and chitin, as well as micronutrients, such as minerals, vitamins and phenolic compounds. Considering their content of bioactive compounds, they offer a sustainable solution to meet future food demands while providing potential health benefits. This review identifies bioactive peptides, phenolic compounds, chitosan, and vitamins as major bioactive ingredients derived from insects. It discusses their presence in various edible insect species, their primary bioactive properties, and methods for production and isolation. Bioactive compounds sourced from edible insects exhibit antioxidant, antimicrobial, and disease-preventing properties. Insects also serve as rich sources of vitamins A, B2, B6, B12, D, and E, albeit with variations in content among species and life stages. However, the consumption of insects poses risks related to their biological and chemical contaminants, as well as their allergenicity. Managed diets in farm-bred insects ensure controlled nutrient levels, highlighting their potential as sustainable sources of bioactive compounds for human health. Adequate processing and labeling of insect-derived products can reduce the risk of insect consumption. In conclusion, the bioactive compound profile of edible insects complements their nutritional richness and highlights their potential to address future nutrition and food security.

Exploring the Potential of Chitosan-Phytochemical Composites in Preventing the Contamination of Antibiotic-Resistant Bacteria on Food Surfaces: A Review

The escalating presence of antibiotic-resistant bacteria (ARB) in food systems presents a pressing challenge, particularly in preventing contamination and ensuring food safety. Traditional sanitation methods, such as cooking and chemical disinfectants, provide effective means to reduce ARB, yet there is a growing need for additional preventive measures directly on food surfaces. This review explores the potential of chitosan-phytochemical composites (CPCs) as surface coatings to prevent the initial contamination of food by ARB, thereby offering a novel complementary approach to conventional food safety practices. Chitosan, combined with active plant-derived metabolites (phytochemicals), forms composites with notable antibacterial and antioxidant properties that enhance its protective effects. We examine CPC synthesis methodologies, including chemical modifications, free radical-induced grafting, and enzyme-mediated techniques, which enhance the stability and activity of CPCs against ARB. Highlighting recent findings on CPCs' antibacterial efficacy through minimum inhibitory concentrations (MIC) and zones of inhibition, this review underscores its potential to reduce ARB contamination risks on food surfaces, particularly in seafood, meat, and postharvest products. The insights provided here aim to encourage future strategies leveraging CPCs as a preventative surface treatment to mitigate ARB in food production and processing environments.

Injectable Chitosan Hydrogel Particles as Nasal Packing Materials After Endoscopic Sinus Surgery for Treatment of Chronic Sinusitis

After endoscopic sinus surgery (ESS), nasal packing is often used to stop bleeding and promote wound healing. Because maintaining a moist environment is important to enhance wound healing, hydrogel-based wound dressings are effective to promote wound healing. Chitosan is used in the medical field because of its high hemostatic and wound healing properties. We developed a pH-neutral and non-toxic chitosan hydrogel, which was difficult to achieve using conventional methods. In this study, we show in animal experiments that the chitosan hydrogel (hydrogel particles) had higher wound healing properties than a commercially available solid wound dressing (dry state) composed of the same polymer. Additionally, we applied the injectable chitosan hydrogel particles as nasal packing materials to patients with bilateral chronic sinusitis undergoing ESS in a pilot clinical study. Concerning symptom scores, though the results narrowly missed statistical differences (p < 0.05), the average scores of our chitosan hydrogel were superior to those of a commercially available wound dressing (especially p = 0.09 for nasal bleeding). These findings suggest that the injectable chitosan hydrogel could be a viable option as a packing material following ESS.

Chitosan-grafted Graphene Materials for Drug Delivery in Wound Healing

The effective and prompt treatment of wounds remains a significant challenge in clinical settings. Consequently, recent investigations have led to the development of a novel wound dressing production designed to expedite the process of wound healing with minimal adverse complications. Chitosan, identified as a natural biopolymer, emerges as an appealing option for fabricating environmentally friendly dressings due to its biologically degradable, nonpoisonous, and inherent antimicrobial properties. Concurrently, graphene oxide has garnered attention from researchers as an economical, biocompatible material with non-toxic attributes for applications in wound healing. Chitosan (CS) has been extensively studied in agglutination owing to its advantageous properties, such as Non-toxicity biological compatibility, degradability, and facilitation of collagen precipitation. Nonetheless, its limited Medium mechanical and antibacterial strength characteristics impede its widespread clinical application. In addressing these shortcomings, numerous researchers have embraced nanotechnology, specifically incorporating metal nanoparticles (MNPs), to enhance the mechanical power and targeted germicide features of chitosan multistructures, yielding hopeful outcomes. Additionally, chitosan is a decreasing factor for MNPs, contributing to reduced cytotoxicity. Consequently, the combination of CS with MNPs manifests antibacterial function, superior mechanical power, and anti-inflammatory features, holding significant potential to expedite wound healing. This study delves into based on chitosan graphene materials in the context of wound healing.

Evaluation of smart bi-functional dressing based on polysaccharide hydrogels and Brassica oleracea extract for wound healing and continuous monitoring

Skin wounds can drive global impacts, socially and economically, in parallel with their elevated incidence rate. Therefore, utilizing the dual-activity of Brassica Oleracea (Red Cabbage) extract, of being pH-sensitive and biologically active in designing novel, therapeutic, and pH-sensitive wound dressings with an easily stripped-off feature, is critical. Wound dressings were designed using two separate hydrogels based on chitosan (CS) and hydroxyethylcellulose (HEC), each loaded with RCE. The pH sensitivity of prepared bandages exhibited a noticeable visual change in color during wound treatment. Wound closure has reached 99.69 % for CS/RCE dressings. Results showed that RCE had raised the hydroxyproline and collagen content in the healed skin. Histopathological investigation proves that skin returned to its regular thickness within 10 days of treatment. RCE showed marked improvement in the healing quality by acting as an antioxidant, anti-inflammatory, and antimicrobial agent. Therefore, dual-function dressings are potential candidates to sense and cure skin wounds.

A novel chitosan-peptide system for cartilage tissue engineering with adipose-derived stromal cells

The natural healing process of cartilage injuries often fails to fully restore the tissue's biological and mechanical functions. Cartilage grafts are costly and require surgical intervention, often associated with complications such as intraoperative infection and rejection by the recipient due to ischemia. Novel tissue engineering technologies aim to ideally fill the cartilage defect to prevent disease progression or regenerate damaged tissue. Despite many studies on designing biocompatible composites to stimulate chondrogenesis, only few focus on peptides and carriers that promote stem cell proliferation or differentiation to promote healing. Our research aimed to design a carbohydrate chitosan-based biomaterial to stimulate stem cells into the chondrogenesis pathway. Our strategy was to combine chitosan with a novel peptide (UG28) that sequence was based on the copin protein. The construct stimulated human adipose-derived stem cells (AD-SCs) cells to undergo chondrogenic differentiation. Chitosan 75/500 allows AD-SCs to grow and has no harmful effects on the cells. The combination of UG28 peptide with the chitosan composite offers promising properties for cell differentiation, indicating its potential for clinical applications in cartilage regeneration.

Natural polymer nanofiber dressings for effective management of chronic diabetic wounds: A comprehensive review

Diabetic wounds present a chronic challenge in effective treatment. Natural polymer nanofiber dressings have emerged as a promising solution due to their impressive biocompatibility, biodegradability, safety, high specific surface area, and resemblance to the extracellular matrix. These qualities make them ideal materials with excellent biological properties and cost-effectiveness. Additionally, they can effectively deliver therapeutic agents, enabling diverse treatment effects. This review offers a comprehensive overview of natural polymer-based nanofibers in diabetic wound dressings. It examines the characteristics and challenges associated with diabetic wounds and the role of natural polymers in facilitating wound healing. The review highlights the preparation, mechanism, and applications of various functional dressings composed of natural polymer nanofibers. Furthermore, it addresses the main challenges and future directions in utilizing natural polymer nanofibers for diabetic wound treatment, providing valuable insights into effective wound management for diabetic patients.

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.

Ionically assembled hemostatic powders with rapid self-gelation, strong acid resistance, and on-demand removability for upper gastrointestinal bleeding

Upper gastrointestinal bleeding (UGIB) is bleeding in the upper part of the gastrointestinal tract with an acidic and dynamic environment that limits the application of conventional hemostatic materials. This study focuses on the development of N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride/phytic acid (HTCC/PA, HP) powders with fast hemostatic capability and strong acid resistance, for potential applications in managing UGIB. Upon contact with liquids within 5 seconds, HP powders rapidly transform into hydrogels, forming ionic networks through electrostatic interactions. The ionic crosslinking process facilitates the HP powders with high blood absorption (3.4 times of self-weight), sufficient tissue adhesion (5.2 and 6.1 kPa on porcine skin and stomach, respectively), and hemostasis (within 15 seconds for in vitro clotting). Interestingly, the PA imparts the HP powders with strong acid resistance (69.8% mass remaining after 10 days of incubation at pH 1) and on-demand removable sealing while HTCC contributes to fast hemostasis and good wet adhesion. Moreover, the HP powders show good biocompatibility and promote wound healing. Therefore, these characteristics highlight the promising clinical potential of HP powders for effectively managing UGIB.

Chitosan-Based Nanoformulations: Preclinical Investigations, Theranostic Advancements, and Clinical Trial Prospects for Targeting Diverse Pathologies

Chitosan, a biocompatible and biodegradable polymer, has attracted significant interest in the development of nanoformulations for targeted drug delivery and therapeutic applications. The versatility of chitosan lies in its modifiable functional groups, which can be tailored to diverse applications. Nanoparticles derived from chitosan and its derivatives typically exhibit a positive surface charge and mucoadhesive properties, enabling them to adhere to negatively charged biological membranes and gradually release therapeutic agents. This comprehensive review investigates the manifold roles of chitosan-based nanocarriers, ranging from preclinical research to theranostic applications and clinical trials, across a spectrum of diseases, including neurological disorders, cardiovascular diseases, cancer, wound healing, gastrointestinal disorders, and pulmonary diseases. The exploration starts with an overview of preclinical studies, emphasizing the potential of chitosan-based nanoformulations in optimizing drug delivery, improving therapeutic outcomes, and mitigating adverse effects in various disease categories. Advancements in theranostic applications of chitosan-based nanoformulations highlight their adaptability to diverse diseases. As these nanoformulations progress toward clinical translation, this review also addresses the regulatory challenges associated with their development and proposes potential solutions.

Synthesis and Characterization of Multifunctional Chitosan-Silver Nanoparticles: An In-Vitro Approach for Biomedical Applications

Antibiotics are successful in promoting health quality by preventing various infectious diseases and minimizing mortality and morbidity all over the world. However, the indiscriminate use of antibiotics has led to the emergence of multi-drug-resistant bacteria, which pose a serious threat to health care sector. Therefore, it is necessary to develop novel antimicrobial agents with versatile characteristics, such as antibacterial activity, low toxicity, wound healing potency, and antioxidant property. In this context, silver chitosan nanoparticles were synthesized in the present study, and their physical characterization revealed that the size of synthesized chitosan-silver nanoparticles was 14-25 nm, with positive surface charge. The functional groups and crystalline nature of the nanoparticles were confirmed by FT-IR and XRD analysis. Further, the silver chitosan nanoparticles showed antibacterial activity against two important clinical pathogens, S. aureus and E. coli. The MTT assay carried out in the present study showed that the synthesized nanoparticles are non-toxic to host cells. A scratch assay on fibroblast cells (L292) demonstrated that the silver chitosan nanoparticles showed promising wound healing activity. A fluorescent DCFH-DA staining assay revealed anantioxidant property of the synthesized nanoparticles. Overall, the study emphasizes the versatile nature of synthesized chitosan-silver nanoparticles, suggesting their great compatibility for biomedical applications.

Fabrication of Mupirocin-Loaded PEGylated Chitosan Nanoparticulate Films for Enhanced Wound Healing

Chitosan-based biomaterials are being investigated for their unique properties that support skin regeneration and wound healing. This study focused on the preparation and characterization of a mupirocin (Mup)-loaded PEGylated chitosan (CS-PEG) nanoparticulate film (NF) [CBNF]. The CBNF was characterized using FTIR spectroscopy and SEM analysis. The results demonstrated that CBNF was successfully incorporated into the composites, as shown by functional group modification through FTIR analysis. Additionally, the SEM micrograph revealed the deposition of nanoparticles (<200 nm) on the surface of transparent CBNF. The film has higher water absorption (≥1700%) and moderate water retention ability within 6 h. Furthermore, histological findings showed significant development, with re-epithelialization and granulation of tissues after 19 days, indicating the healing efficiency of CNBF. These results suggest that drug-loaded films could be an effective carrier and delivery agent for Mup-like anti-inflammatory drugs.

All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies

The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.

Recent Applications of Chitosan and Its Derivatives in Antibacterial, Anticancer, Wound Healing, and Tissue Engineering Fields

Chitosan, a versatile biopolymer derived from chitin, has garnered significant attention in various biomedical applications due to its unique properties, such as biocompatibility, biodegradability, and mucoadhesiveness. This review provides an overview of the diverse applications of chitosan and its derivatives in the antibacterial, anticancer, wound healing, and tissue engineering fields. In antibacterial applications, chitosan exhibits potent antimicrobial properties by disrupting microbial membranes and DNA, making it a promising natural preservative and agent against bacterial infections. Its role in cancer therapy involves the development of chitosan-based nanocarriers for targeted drug delivery, enhancing therapeutic efficacy while minimising side effects. Chitosan also plays a crucial role in wound healing by promoting cell proliferation, angiogenesis, and regulating inflammatory responses. Additionally, chitosan serves as a multifunctional scaffold in tissue engineering, facilitating the regeneration of diverse tissues such as cartilage, bone, and neural tissue by promoting cell adhesion and proliferation. The extensive range of applications for chitosan in pharmaceutical and biomedical sciences is not only highlighted by the comprehensive scope of this review, but it also establishes it as a fundamental component for forthcoming research in biomedicine.

Biopolymer based nanoparticles and their therapeutic potential in wound healing - A review

Nanoparticles (NPs) have been extensively investigated for their potential in nanomedicine. There is a significant level of enthusiasm about the potential of NPs to bring out a transformative impact on modern healthcare. NPs can serve as effective wound dressings or delivery vehicles due to their antibacterial and pro-wound-healing properties. Biopolymer-based NPs can be manufactured using various food-grade biopolymers, such as proteins, polysaccharides, and synthetic polymers, each offering distinct properties suitable for different applications which include collagen, polycaprolactone, chitosan, alginate, and polylactic acid, etc. Their biodegradable and biocompatible nature renders them ideal nanomaterials for applications in wound healing. Additionally, the nanofibers containing biopolymer-based NPs have shown excellent anti-bacterial and wound healing activity like silver NPs. These NPs represent a paradigm shift in wound healing therapies, offering targeted and personalized solutions for enhanced tissue regeneration and accelerated wound closure. The current review focuses on biopolymer NPs with their applications in wound healing.

Evaluation of the restorative effect of ozone and chitosan-hyaluronic acid with and without mesenchymal stem cells on wound healing in rats

This study evaluated the effect of ozone, chitosan-hyaluronic (Cs-HA) acid and mesenchymal stem cells (MSCs) on wound healing in rats. A total of 64 rats were randomly divided into four groups: control, ozone, Cs-HA + ozone and Cs-HA + ozone + MSCs. A 5 mm full-thickness wound was created on the back of each rat. The wound area was measured macroscopically on days 3, 5, 9 and 14. Tissue sections were prepared for histopathological evaluation of inflammation, collagen arrangement, neovascularization and epithelial tissue rearrangement. Macroscopic assessment showed differences in wound area on days 5, 9 and 14. Histopathological examination showed that the Cs-HA + ozone + MSCs and Cs-HA + ozone groups had significantly higher vascularization on day 3 compared to the ozone-treated and control groups. All treatment groups had significantly better collagen arrangement than the control group. On day 5, no significant difference was observed between different groups. On day 9, the inflammation level in the Cs-HA + ozone + MSCs group was significantly lower than in the other groups. All treatment groups had significantly better vascularization compared to the control group. On day 14, the rate of inflammation was significantly lower in the treatment groups than in the control group. Significantly higher collagen arrangement levels were observed in the Cs-HA + ozone and Cs-HA + ozone + MSCs groups compared to the control and ozone groups. All treatment groups had significantly better epithelial tissue rearrangement than the control group. Overall, the results of this study indicated that treatment with ozone, Cs-HA acid, Cs-HA and MSCs accelerated wound healing in rats. The effect of using Cs-HA acid with mesenchymal cells was better than the other types of treatment. Larger clinical trials are needed to assess these factors for improving chronic wound treatment.

Hydrogel-based immunoregulation of macrophages for tissue repair and regeneration

The rational design of hydrogel materials to modulate the immune microenvironment has emerged as a pivotal approach in expediting tissue repair and regeneration. Within the immune microenvironment, an array of immune cells exists, with macrophages gaining prominence in the field of tissue repair and regeneration due to their roles in cytokine regulation to promote regeneration, maintain tissue homeostasis, and facilitate repair. Macrophages can be categorized into two types: classically activated M1 (pro-inflammatory) and alternatively activated M2 (anti-inflammatory and pro-repair). By regulating the physical and chemical properties of hydrogels, the phenotypic transformation and cell behavior of macrophages can be effectively controlled, thereby promoting tissue regeneration and repair. A full understanding of the interaction between hydrogels and macrophages can provide new ideas and methods for future tissue engineering and clinical treatment. Therefore, this paper reviews the effects of hydrogel components, hardness, pore size, and surface morphology on cell behaviors such as macrophage proliferation, migration, and phenotypic polarization, and explores the application of hydrogels based on macrophage immune regulation in skin, bone, cartilage, and nerve tissue repair. Finally, the challenges and future prospects of macrophage-based immunomodulatory hydrogels are discussed.

Preparation and characterization of chitosan/polyvinyl alcohol antibacterial sponge materials

This study utilized the freeze-drying method to create a chitosan (CS) and polyvinyl alcohol (PVA) sponge. To enhance its antibacterial properties, curcumin and nano silver (Cur@Ag) were added for synergistic antibacterial. After adding curcumin and nano silver, the mechanical properties of the composite sponge dressing (CS-PVA-Cur@Ag) were improved. The porosity of the composite sponge dressing was closed to 80%, which was helpful for drug release, and it had good water absorption and water retention rate. The nano silver diameter was 50-80 nm, which was optimal for killing bacteria. Antibacterial tests usedEscherichia coliandStaphylococcus aureusdemonstrated that little nano silver was required to eliminate bacteria. Finally, in the rat full-thickness skin wound model, the composite sponge dressing can promote wound healing in a short time. In summary, CS-PVA-Cur@Ag wound dressing could protect from bacterial infection and accelerate wound healing. Thus, it had high potential application value for wound dressing.

Recent Advances in Topical Hemostatic Materials

Untimely or improper treatment of traumatic bleeding may cause secondary injuries and even death. The traditional hemostatic modes can no longer meet requirements of coping with complicated bleeding emergencies. With scientific and technological advancements, a variety of topical hemostatic materials have been investigated involving inorganic, biological, polysaccharide, and carbon-based hemostatic materials. These materials have their respective merits and defects. In this work, the application and mechanism of the major hemostatic materials, especially some hemostatic nanomaterials with excellent adhesion, good biocompatibility, low toxicity, and high adsorption capacity, are summarized. In the future, it is the prospect to develop multifunctional hemostatic materials with hemostasis and antibacterial and anti-inflammatory properties for promoting wound healing.

Exploring polysaccharide-based bio-adhesive topical film as a potential platform for wound dressing application: A review

Wound dressings act as a physical barrier between the wound site and the external environment, preventing additional harm; choosing suitable wound dressings is essential for the healing process. Polysaccharide biopolymers have demonstrated encouraging findings and therapeutic prospects in recent decades about wound therapy. Additionally, polysaccharides have bioactive qualities like anti-inflammatory, antibacterial, and antioxidant capabilities that can help the process of healing. Due to their excellent tissue adhesion, swelling, water absorption, bactericidal, and immune-regulating properties, polysaccharide-based bio-adhesive films have recently been investigated as intriguing alternatives in wound management. These films also mimic the structure of the skin and stimulate the regeneration of the skin. This review presented several design standards and functions of suitable bio-adhesive films for the healing of wounds. Additionally, the most recent developments in the use of bio-adhesive films as wound dressings based on polysaccharides, including hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, cellulose, konjac glucomannan, gellan gum, xanthan gum, pectin, guar gum, heparin, arabinogalactans, carrageen, and tragacanth gum, are thoroughly discussed. Lastly, to create a road map for the function of polysaccharide-based bio-adhesive films in advanced wound care, their clinical performances and future challenges in making bio-adhesive films by three-dimensional bioprinting are summarized.

Use of Biomaterials in 3D Printing as a Solution to Microbial Infections in Arthroplasty and Osseous Reconstruction

The incidence of microbial infections in orthopedic prosthetic surgeries is a perennial problem that increases morbidity and mortality, representing one of the major complications of such medical interventions. The emergence of novel technologies, especially 3D printing, represents a promising avenue of development for reducing the risk of such eventualities. There are already a host of biomaterials, suitable for 3D printing, that are being tested for antimicrobial properties when they are coated with bioactive compounds, such as antibiotics, or combined with hydrogels with antimicrobial and antioxidant properties, such as chitosan and metal nanoparticles, among others. The materials discussed in the context of this paper comprise beta-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP), hydroxyapatite, lithium disilicate glass, polyetheretherketone (PEEK), poly(propylene fumarate) (PPF), poly(trimethylene carbonate) (PTMC), and zirconia. While the recent research results are promising, further development is required to address the increasing antibiotic resistance exhibited by several common pathogens, the potential for fungal infections, and the potential toxicity of some metal nanoparticles. Other solutions, like the incorporation of phytochemicals, should also be explored. Incorporating artificial intelligence (AI) in the development of certain orthopedic implants and the potential use of AI against bacterial infections might represent viable solutions to these problems. Finally, there are some legal considerations associated with the use of biomaterials and the widespread use of 3D printing, which must be taken into account.

Pharmaceutical applications of chitosan in skin regeneration: A review

Skin regeneration is the process that restores damaged tissues. When the body experiences trauma or surgical incisions, the skin and tissues on the wound surface become damaged. The body repairs this damage through complex physiological processes to restore the original structural and functional states of the affected tissues. Chitosan, a degradable natural bioactive polysaccharide, has attracted widespread attention partly owing to its excellent biocompatibility and antimicrobial properties; additionally, a modified form of this compound has been shown to promote skin regeneration. This review evaluates the recent research progress in the application of chitosan to promote skin regeneration. First, we discuss the basic principles of the extraction and preparation processes of chitosan from its source. Subsequently, we describe the functional properties of chitosan and the optimization of these properties through modification. We then focus on the existing chitosan-based biomaterials developed for clinical applications and their corresponding effects on skin regeneration, particularly in cases of diabetic and burn wounds. Finally, we explore the challenges and prospects associated with the use of chitosan in skin regeneration. Overall, this review provides a reference for related research and contributes to the further development of chitosan-based products in cutaneous skin regeneration.

Microwave-assisted synthesis of crosslinked ureido chitosan for hemostatic applications

In this study, we present a facile method for introducing hydrophilic ureido groups (NH2-CO-NH-) into chitosan using a microwave-assisted reaction with molten urea, with the aim of enhancing chitosan's interaction with blood components for improved hemostasis. The formation of the ureido groups through nucleophilic addition reaction between the amine groups in chitosan and in situ generated isocyanic acid was confirmed by FTIR, CP/TOSS 13C NMR, and CP/MAS 15N NMR spectroscopic techniques. However, in stark contrast to the glucans, the said modification introduced extensive crosslinking in chitosan. Spectroscopic studies identified these crosslinks as carbamate bridges (-NH-COO-), which were likely formed by the reaction between the ureido groups and hydroxyl groups of adjacent chains through an isocyanate intermediate. These carbamate bridges improved ureido chitosan's environmental stability, making it particularly resistant to changes in pH and temperature. In comparison to chitosan, the crosslinked ureido chitosan synthesized here exhibited good biocompatibility and cell adhesion, rapidly arrested the bleeding in a punctured artery with minimal hemolysis, and induced early activation and aggregation of platelets. These properties render it an invaluable material for applications in hemostasis, particularly in scenarios that necessitate stability against pH variations and degradation.

Biodegradable Polymers in Veterinary Medicine-A Review

During the past two decades, tremendous progress has been made in the development of biodegradable polymeric materials for various industrial applications, including human and veterinary medicine. They are promising alternatives to commonly used non-degradable polymers to combat the global plastic waste crisis. Among biodegradable polymers used, or potentially applicable to, veterinary medicine are natural polysaccharides, such as chitin, chitosan, and cellulose as well as various polyesters, including poly(ε-caprolactone), polylactic acid, poly(lactic-co-glycolic acid), and polyhydroxyalkanoates produced by bacteria. They can be used as implants, drug carriers, or biomaterials in tissue engineering and wound management. Their use in veterinary practice depends on their biocompatibility, inertness to living tissue, mechanical resistance, and sorption characteristics. They must be designed specifically to fit their purpose, whether it be: (1) facilitating new tissue growth and allowing for controlled interactions with living cells or cell-growth factors, (2) having mechanical properties that address functionality when applied as implants, or (3) having controlled degradability to deliver drugs to their targeted location when applied as drug-delivery vehicles. This paper aims to present recent developments in the research on biodegradable polymers in veterinary medicine and highlight the challenges and future perspectives in this area.

Comparative Analysis of Antibacterial and Wound Healing Activities of Chitosan and Povidone-Iodine-Based Hydrogels

PURPOSE

This study aimed to compare the antibacterial and wound healing efficacies of chitosan hydrogel with povidone-iodine (PI) hydrogel.

METHODS

The in vitro antibacterial activities of chitosan and PI hydrogels against Staphylococcus aureus and Escherichia coli were evaluated. Nine 6- to 8-week-old male Sprague-Dawley rats were divided into plain, PI, and chitosan hydrogel groups. Each rat received two 10-mm full-thickness dorsal wounds using an excisional splinting model. Each wound was treated with 0.2 mL of gel thrice over the course of 3 postoperative weeks. Weekly observations were conducted, and at the end of the third postoperative week, the rats were killed for histopathological and quantitative polymerase chain reaction evaluations. Data analysis included both 2- and 1-way analyses of variance.

RESULTS

Chitosan hydrogel exhibited comparable in vitro antibacterial activity and a significantly enhanced in vivo wound closure rate compared with PI hydrogel. Three weeks after the surgery, the chitosan hydrogel group demonstrated marked differences in wound repair (P < 0.01). Histologically, increased collagen deposition was observed with chitosan hydrogel treatment. Immunohistochemistry for CD68 revealed a lower number of macrophages in the wounds treated with chitosan hydrogel. Quantitative polymerase chain reaction analysis indicated a superior collagen 1 to 3 ratio and reduced expression of proinflammatory cytokine mRNAs (interleukin 1b, interleukin 6, tumor necrosis factor α, and interferon γ) in the chitosan hydrogel group.

CONCLUSION

Chitosan hydrogel demonstrates the potential to serve as an effective alternative to PI hydrogel, providing enhanced wound healing capabilities while maintaining comparable antimicrobial properties.

Electrospun Antimicrobial Drug Delivery Systems and Hydrogels Used for Wound Dressings

Wounds and chronic wounds can be caused by bacterial infections and lead to discomfort in patients. To solve this problem, scientists are working to create modern wound dressings with antibacterial additives, mainly because traditional materials cannot meet the general requirements for complex wounds and cannot promote wound healing. This demand is met by material engineering, through which we can create electrospun wound dressings. Electrospun wound dressings, as well as those based on hydrogels with incorporated antibacterial compounds, can meet these requirements. This manuscript reviews recent materials used as wound dressings, discussing their formation, application, and functionalization. The focus is on presenting dressings based on electrospun materials and hydrogels. In contrast, recent advancements in wound care have highlighted the potential of thermoresponsive hydrogels as dynamic and antibacterial wound dressings. These hydrogels contain adaptable polymers that offer targeted drug delivery and show promise in managing various wound types while addressing bacterial infections. In this way, the article is intended to serve as a compendium of knowledge for researchers, medical practitioners, and biomaterials engineers, providing up-to-date information on the state of the art, possibilities of innovative solutions, and potential challenges in the area of materials used in dressings.

Cross-Linked Alginate Dialdehyde/Chitosan Hydrogel Encompassing Curcumin-Loaded Bilosomes for Enhanced Wound Healing Activity

The current study aimed to fabricate curcumin-loaded bilosomal hydrogel for topical wound healing purposes, hence alleviating the poor aqueous solubility and low oral bioavailability of curcumin. Bilosomes were fabricated via the thin film hydration technique using cholesterol, Span® 60, and two different types of bile salts (sodium deoxycholate or sodium cholate). Bilosomes were verified for their particle size (PS), polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE%), and in vitro drug release besides their morphological features. The optimum formulation was composed of cholesterol/Span® 60 (molar ratio 1:10 w/w) and 5 mg of sodium deoxycholate. This optimum formulation was composed of a PS of 246.25 ± 11.85 nm, PDI of 0.339 ± 0.030, ZP of -36.75 ± 0.14 mv, EE% of 93.32% ± 0.40, and the highest percent of drug released over three days (96.23% ± 0.02). The optimum bilosomal formulation was loaded into alginate dialdehyde/chitosan hydrogel cross-linked with calcium chloride. The loaded hydrogel was tested for its water uptake capacity, in vitro drug release, and in vivo studies on male Albino rats. The results showed that the loaded hydrogel possessed a high-water uptake percent at the four-week time point (729.50% ± 43.13) before it started to disintegrate gradually; in addition, it showed sustained drug release for five days (≈100%). In vivo animal testing and histopathological studies supported the superiority of the curcumin-loaded bilosomal hydrogel in wound healing compared to the curcumin dispersion and plain hydrogel, where there was a complete wound closure attained after the three-week period with a proper healing mechanism. Finally, it was concluded that curcumin-loaded bilosomal hydrogel offered a robust, efficient, and user-friendly dosage form for wound healing.

A multifunctional and self-adaptive double-layer hydrogel dressing based on chitosan for deep wound repair

Hydrogel wound dressing for irregular shape and deep wound repair is a research hotspot. Herein, a multifunctional and self-adaptive double-layer hydrogel was constructed, which was comprised of chitosan-based inner layer hydrogel and gellan gum-based outer layer hydrogel. Various properties of inner layer hydrogel were systematically investigated, including injectability, shape-adaptability, solid-liquid phase transition, biocompatibility, hemostasis, antibacterial performance and anti-inflammatory. Thanks to the phase-transition from solid to liquid at body temperature, inner layer hydrogel exhibited stronger adaptability to fill irregular and deep wounds, in which chitosan was liquefied and its therapeutic effect was maximized. Outer layer hydrogel was fabricated by calcium ions and gellan gum, whose certain mechanical strength could provide protection and a moister environment for wounds. Because of these characteristics, double-layer hydrogel markedly promoted skin tissue regeneration and wound closure and thereby possessed potential clinical application prospect as wound dressing for deep wounds.

Cationic Porphyrins as Antimicrobial and Antiviral Agents in Photodynamic Therapy

Antimicrobial photodynamic therapy (APDT) has received a great deal of attention due to its unique ability to kill all currently known classes of microorganisms. To date, infectious diseases caused by bacteria and viruses are one of the main sources of high mortality, mass epidemics and global pandemics among humans. Every year, the emergence of three to four previously unknown species of viruses dangerous to humans is recorded, totaling more than 2/3 of all newly discovered human pathogens. The emergence of bacteria with multidrug resistance leads to the rapid obsolescence of antibiotics and the need to create new types of antibiotics. From this point of view, photodynamic inactivation of viruses and bacteria is of particular interest. This review summarizes the most relevant mechanisms of antiviral and antibacterial action of APDT, molecular targets and correlation between the structure of cationic porphyrins and their photodynamic activity.

Functional Analysis of Injectable Substance Treatment on Surgically Injured Rabbit Vocal Folds

OBJECTIVES

The objective of this study was to evaluate the efficacy of immediate injection treatments of dexamethasone, hyaluronic acid (HA)/gelatin (Ge) hydrogel and glycol-chitosan solution on the phonatory function of rabbit larynges at 42 days after surgical injury of the vocal folds, piloting a novel ex vivo phonatory functional analysis protocol.

METHODS

A modified microflap procedure was performed on the left vocal fold of 12 rabbits to induce an acute injury. Animals were randomized into one of four treatment groups with 0.1 mL injections of dexamethasone, HA/Ge hydrogel, glycol-chitosan or saline as control. The left mid vocal fold lamina propria was injected immediately following injury. The right vocal fold served as an uninjured control. Larynges were harvested at Day 42 after injection, then were subjected to airflow-bench evaluation. Acoustic, aerodynamic and laryngeal high-speed videoendoscopy (HSV) analyses were performed. HSV segments of the vibrating vocal folds were rated by three expert laryngologists. Six parameters related to vocal fold vibratory characteristics were evaluated on a Likert scale.

RESULTS

The fundamental frequency, one possible surrogate of vocal fold stiffness and scarring, was lower in the dexamethasone and HA/Ge hydrogel treatment groups compared to that of the saline control (411.52±11.63 Hz). The lowest fundamental frequency value was observed in the dexamethasone group (348.79±14.99 Hz). Expert visual ratings of the HSV segments indicated an overall positive outcome in the dexamethasone treatment group, though the impacts were below statistical significance.

CONCLUSION

Dexamethasone injections might be used as an adjunctive option for iatrogenic vocal fold scarring. An increased sample size, histological correlate, and experimental method improvements will be needed to confirm this finding. Results suggested a promising use of HSV and acoustic analysis techniques to identify and monitor post-surgical vocal fold repair and scarring, providing a useful tool for future studies of vocal fold scar treatments.

Emerging Advances in Microfluidic Hydrogel Droplets for Tissue Engineering and STEM Cell Mechanobiology

Hydrogel droplets are biodegradable and biocompatible materials with promising applications in tissue engineering, cell encapsulation, and clinical treatments. They represent a well-controlled microstructure to bridge the spatial divide between two-dimensional cell cultures and three-dimensional tissues, toward the recreation of entire organs. The applications of hydrogel droplets in regenerative medicine require a thorough understanding of microfluidic techniques, the biocompatibility of hydrogel materials, and droplet production and manipulation mechanisms. Although hydrogel droplets were well studied, several emerging advances promise to extend current applications to tissue engineering and beyond. Hydrogel droplets can be designed with high surface-to-volume ratios and a variety of matrix microstructures. Microfluidics provides precise control of the flow patterns required for droplet generation, leading to tight distributions of particle size, shape, matrix, and mechanical properties in the resultant microparticles. This review focuses on recent advances in microfluidic hydrogel droplet generation. First, the theoretical principles of microfluidics, materials used in fabrication, and new 3D fabrication techniques were discussed. Then, the hydrogels used in droplet generation and their cell and tissue engineering applications were reviewed. Finally, droplet generation mechanisms were addressed, such as droplet production, droplet manipulation, and surfactants used to prevent coalescence. Lastly, we propose that microfluidic hydrogel droplets can enable novel shear-related tissue engineering and regeneration studies.

Resveratrol-loaded co-axial electrospun poly(ε-caprolactone)/chitosan/polyvinyl alcohol membranes for promotion of cells osteogenesis and bone regeneration

The guided bone regeneration (GBR) membranes currently used in clinics are usually compromised by their limited osteogenic induction potential. In this study, we fabricate a core-shell poly(ε-caprolactone)/chitosan/polyvinyl alcohol (PCL/CS/PVA) GBR membrane with different amount of resveratrol (RSV), endowing the PCL/CS/PVA GBR membrane with superior osteogenic induction ability, which was not attained by the regular GBR membrane. The prepared GBR membranes were characterized by scanning electron microscopy, transmission electron microscopy, and CCK-8 and live-dead staining assays, and their osteogenic induction ability was evaluated using Col-I immunofluorescence staining, micro-computed tomography, haematoxylin and eosin staining and immunohistochemical staining. Results of the in vitro release experiment confirmed that the membranes exhibited a continuous RSV release profile for 15 days. Furthermore, the cumulative releasing of RSV was increased from 39.68 ± 2.09 μg to 65.8 ± 2.91 μg with increasing contents of RSV from 0.1 % to 0.5 % (w/v) in the core layer of GBR membranes. In particular, the PCL/CS/PVA GBR membrane loading with 0.5 % RSV most efficiently release RSV in a sustained and controlled manner, which significantly induced osteogenic differentiation of pre-osteoblasts in vitro and bone regeneration in vivo. Based on the in vivo histological findings, newly formed bone tissues with 82.46 ± 9.86 % BV/TV and 0.70 ± 0.07gcm-3 BMD were generated in the defect sites treated by the GBR membrane loaded with 0.5 % RSV, which were the largest values among those for all three groups after 12 weeks of post implantation. Overall, the PCL/CS/PVA GBR membrane loaded with 0.5 % RSV has significant potential for bone regeneration.

Two-phase matrices for the controlled release of therapeutic proteins

Controlled and sustained delivery of therapeutic proteins is crucial for achieving desired effects in wound healing applications. Yet, this remains a challenge in growth factor delivery for bone tissue engineering. Current delivery systems can lead to negative side effects, such as ectopic bone growth and cancer, due to the over administration of growth inducing proteins. Here, we have developed a two-phase system for the controlled release of therapeutic proteins. The system consists of protein-loaded poly(methacrylic acid)-based nanoparticles conjugated to chitosan scaffolds. The effect of co-monomer hydrophilicity and crosslinking density on nanoparticle properties was evaluated. It was found that the release kinetics of model therapeutic proteins were dependent on nanoparticle hydrophilicity. The chitosan scaffold, chosen for its biocompatibility and osteogenic properties, provided additional barriers to diffusion and promoted nanoparticle retention, leading to more sustained protein delivery. Additionally, the ability of MC3T3-E1 pre-osteoblast cells to proliferate on scaffolds with and without conjugated nanoparticles was evaluated and all scaffolds were shown to promote cell growth. The results demonstrate that the two-phase scaffold system presents a superior strategy for the sustained and controlled release of therapeutic proteins for bone tissue engineering applications.

Chitosan Particles Complexed with CA5-HIF-1α Plasmids Increase Angiogenesis and Improve Wound Healing

Wound therapies involving gene delivery to the skin have significant potential due to the advantage and ease of local treatment. However, choosing the appropriate vector to enable successful gene expression while also ensuring that the treatment's immediate material components are conducive to healing itself is critical. In this study, we utilized a particulate formulation of the polymer chitosan (chitosan particles, CPs) as a non-viral vector for the delivery of a plasmid encoding human CA5-HIF-1α, a degradation resistant form of HIF-1α, to enhance wound healing. We also compared the angiogenic potential of our treatment (HIF/CPs) to that of chitosan particles containing only the plasmid backbone (bb/CPs) and the chitosan particle vector alone (CPs). Our results indicate that chitosan particles exert angiogenic effects that are enhanced with the human CA5-HIF-1α-encoded plasmid. Moreover, HIF/CPs enhanced wound healing in diabetic db/db mice (p < 0.01), and healed tissue was found to contain a significantly increased number of blood vessels compared to bb/CPs (p < 0.01), CPs (p < 0.05) and no-treatment groups (p < 0.01). Thus, this study represents a method of gene delivery to the skin that utilizes an inherently pro-wound-healing polymer as a vector for plasmid DNA that has broad application for the expression of other therapeutic genes.

Chitosan-Based Hydrogels for Infected Wound Treatment

Wound infections slow down the healing process and lead to complications such as septicemia, osteomyelitis, and even death. Although traditional methods relying on antibiotics are effective in controlling infection, they have led to the emergence of antibiotic-resistant bacteria. Hydrogels with antimicrobial function become a viable option for reducing bacterial colonization and infection while also accelerating healing processes. Chitosan is extensively developed as antibacterial wound dressings due to its unique biochemical properties and inherent antibacterial activity. In this review, the recent research progress of chitosan-based hydrogels for infected wound treatment, including the fabrication methods, antibacterial mechanisms, antibacterial performance, wound healing efficacy, etc., is summarized. A concise assessment of current limitations and future trends is presented.

Vascular Endothelial Growth Factor Supplementation Enhance Skin Antioxidant Capacity in Hyperglycemic Rats

The fundamental reasons for delayed wound healing in diabetic animals include inadequate production of growth factors or their increased devastation. Vascular Growth Factor (VEGF) has a biological role in the healing process of mucosal and skin wounds, especially in the process of new vessel formation. We planned to examine the oxidant-antioxidant events that occur during healing with topical VEGF application in diabetic rats. Experiments were performed 36 adults female Wistar albino rat diabetes induced by streptozotocin. The incisional wounds were made on the dorsal region in the rats. Rats were separated to 3 groups: the untreated (negative control) group (n=12), the chitosan group (n=12), the chitosan + VEGF group (n=12). The treatments were continued for 3 and 7 days, excluding the control and negative control groups. Then, the animals were sacrificed on the 3rd and 7th days of wound healing. Antioxidant and oxidant parameters in skin tissue were measured using biochemical methods. Topical VEGF application was decreased the NOx levels on the 3rd day compared to other groups. Moreover, it increased wound tissue GSH and AA levels, subsequently contributing to the enhance tissue antioxidant capacity. In conclusion, VEGF application increases the antioxidant capacity of the tissue and simultaneously reduces the oxidative stress and thus gives a positive acceleration to the wound healing process.

Synthesis, Characterization and Biological Properties of Type I Collagen-Chitosan Mixed Hydrogels: A Review

Type I collagen and chitosan are two of the main biological macromolecules used to design scaffolds for tissue engineering. The former has the benefits of being biocompatible and provides biochemical cues for cell adhesion, proliferation and differentiation. However, collagen hydrogels usually exhibit poor mechanical properties and are difficult to functionalize. Chitosan is also often biocompatible, but is much more versatile in terms of structure and chemistry. Although it does have important biological properties, it is not a good substrate for mammalian cells. Combining of these two biomacromolecules is therefore a strategy of choice for the preparation of interesting biomaterials. The aim of this review is to describe the different protocols available to prepare Type I collagen-chitosan hydrogels for the purpose of presenting their physical and chemical properties and highlighting the benefits of mixed hydrogels over single-macromolecule ones. A critical discussion of the literature is provided to point out the poor understanding of chitosan-type I collagen interactions, in particular due to the lack of systematic studies addressing the effect of chitosan characteristics.

Review on Additives in Hydrogels for 3D Bioprinting of Regenerative Medicine: From Mechanism to Methodology

The regeneration of biological tissues in medicine is challenging, and 3D bioprinting offers an innovative way to create functional multicellular tissues. One common way in bioprinting is bioink, which is one type of the cell-loaded hydrogel. For clinical application, however, the bioprinting still suffers from satisfactory performance, e.g., in vascularization, effective antibacterial, immunomodulation, and regulation of collagen deposition. Many studies incorporated different bioactive materials into the 3D-printed scaffolds to optimize the bioprinting. Here, we reviewed a variety of additives added to the 3D bioprinting hydrogel. The underlying mechanisms and methodology for biological regeneration are important and will provide a useful basis for future research.

Sustainable Approach of Functional Biomaterials-Tissue Engineering for Skin Burn Treatment: A Comprehensive Review

Burns are a widespread global public health traumatic injury affecting many people worldwide. Non-fatal burn injuries are a leading cause of morbidity, resulting in prolonged hospitalization, disfigurement, and disability, often with resulting stigma and rejection. The treatment of burns is aimed at controlling pain, removing dead tissue, preventing infection, reducing scarring risk, and tissue regeneration. Traditional burn wound treatment methods include the use of synthetic materials such as petroleum-based ointments and plastic films. However, these materials can be associated with negative environmental impacts and may not be biocompatible with the human body. Tissue engineering has emerged as a promising approach to treating burns, and sustainable biomaterials have been developed as an alternative treatment option. Green biomaterials such as collagen, cellulose, chitosan, and others are biocompatible, biodegradable, environment-friendly, and cost-effective, which reduces the environmental impact of their production and disposal. They are effective in promoting wound healing and reducing the risk of infection and have other benefits such as reducing inflammation and promoting angiogenesis. This comprehensive review focuses on the use of multifunctional green biomaterials that have the potential to revolutionize the way we treat skin burns, promoting faster and more efficient healing while minimizing scarring and tissue damage.

Dressing Materials: A Comprehensive Review

Injury to the skin provides a difficult challenge, as wound healing is a complex and dynamic process. Wound healing process recruits three different phases: inflammation, proliferation, and maturation. The sequence of events involved in wound healing can be affected by numerous disease processes, resulting in chronic, non-healing wounds that give significant discomfort and distress to the patients while draining the medical fraternity of enormous resources. Wound tissue never reaches its pre-injured strength and multiple aberrant healing states can result in chronic non-healing wounds. There is a growing concern about the usage of correct materials for wound dressings. The development of new and effective treatments in wound care still remains an area of intense research. There are a number of wound dressings available in the market. The objective of the article is to enhance knowledge about characteristics of an ideal wound dressing and guide in finding the correct dressing material. It also provides a detailed classification of traditional and modern wound dressings.

Autoclaving-Triggered Hydrogelation of Chitosan-Gluconic acid Conjugate Aqueous Solution for Wound Healing

Moist wound healing is known to heal wounds faster than dry wound healing. Hydrogel wound dressings are suitable for moist wound healing because of their hyperhydrous structure. Chitosan, a natural polymer, promotes wound healing by stimulating inflammatory cells and releasing bioactive compounds. Therefore, chitosan hydrogel has great potential as a wound dressing. In our previous study, physically crosslinked chitosan hydrogels were successfully prepared solely by freeze-thawing of chitosan-gluconic acid conjugate (CG) aqueous solution without using any toxic additives. Furthermore, the CG hydrogels could be sterilized by autoclaving (steam sterilization). In this study, we showed that autoclaving (121 °C, 20 min) of a CG aqueous solution simultaneously achieved gelation of the solution and sterilization of the hydrogel. Hydrogelation of CG aqueous solution by autoclaving is also physically crosslinking without any toxic additives. Further, we showed that the CG hydrogels retained favorable biological properties of the CG hydrogels prepared by freeze-thawing and subsequent autoclaving. These results indicated that CG hydrogels prepared by autoclaving were promising as wound dressings.

Effect of Chitosan-Diosgenin Combination on Wound Healing

The difficult-to-heal wounds continue to be a problem for modern medicine. Chitosan and diosgenin possess anti-inflammatory and antioxidant effects making them relevant substances for wound treatment. That is why this work aimed to study the effect of the combined application of chitosan and diosgenin on a mouse skin wound model. For the purpose, wounds (6 mm diameter) were made on mice's backs and were treated for 9 days with one of the following: 50% ethanol (control), polyethylene glycol (PEG) in 50% ethanol, chitosan and PEG in 50% ethanol (Chs), diosgenin and PEG in 50% ethanol (Dg) and chitosan, diosgenin and PEG in 50% ethanol (ChsDg). Before the first treatment and on the 3rd, 6th and 9th days, the wounds were photographed and their area was determined. On the 9th day, animals were euthanized and wounds' tissues were excised for histological analysis. In addition, the lipid peroxidation (LPO), protein oxidation (POx) and total glutathione (tGSH) levels were measured. The results showed that ChsDg had the most pronounced overall effect on wound area reduction, followed by Chs and PEG. Moreover, the application of ChsDg maintained high levels of tGSH in wound tissues, compared to other substances. It was shown that all tested substances, except ethanol, reduced POx comparable to intact skin levels. Therefore, the combined application of chitosan and diosgenin is a very promising and effective medication for wound healing.