Chitosan/Copaiba oleoresin films for would dressing application

Citric acid cross-linked pomegranate peel extract-loaded pH-responsive β-cyclodextrin/carboxymethyl tapioca starch hydrogel film for diabetic wound healing

Pomegranate peel extract (PPE) hydrogel films filled with citric acid (CA) and β-cyclodextrin-carboxymethyl tapioca starch (CMS) were designed mainly to prevent wound infections and speed up the healing process. FTIR and NMR studies corroborated the carboxymethylation of neat tapioca starch (NS). CMS exhibited superior swelling behavior than NS. The amount of CA and β-CD controlled the physicochemical parameters of developed PPE/CA/β-CD/CMS films. Optimized film (OF) exhibited acceptable swellability, wound fluid absorptivity, water vapor transmission rate, water contact angle, and mechanical properties. Biodegradable, biocompatible, and antibacterial films exhibited pH dependence in the release of ellagic acid for up to 24 h. In mice model, PPE/CA/β-CD/CMS hydrogel film treatment showed promising wound healing effects, including increased collagen deposition, reduced inflammation, activation of the Wingless-related integration site (wnt) pathway leading to cell division, proliferation, and migration to the wound site. The expression of the WNT3A gene did not show any significant differences among all the studied groups. Developed PPE-loaded CA/β-CD/CMS film promoted wound healing by epithelialization, granulation tissue thickness, collagen deposition, and angiogenesis, hence could be recommended as a biodegradable and antibacterial hydrogel platform to improve the cell proliferation during the healing of diabetic wounds.

An injectable hydrogel dressing for controlled release of hydrogen sulfide pleiotropically mediates the wound microenvironment

The healing of scalded wounds faces many challenges such as chronic inflammation, oxidative stress, wound infection, and difficulties in vascular and nerve regeneration. Treating a single problem cannot effectively coordinate the complex regenerative microenvironment of scalded wounds, limiting the healing and functional recovery of the skin. Therefore, there is a need to develop a multi-effect treatment plan that can adaptively address the issues at each stage of wound healing. In this study, we propose a scheme for on-demand release of hydrogen sulfide (H2S) based on the concentration of reactive oxygen species (ROS) in the wound microenvironment. This is achieved by encapsulating peroxythiocarbamate (PTCM) in the ROS-responsive polymer poly(ethylene glycol)-poly(L-methionine) (PMet) to form nanoparticles, which are loaded into a thermosensitive injectable hydrogel, F127-poly(L-aspartic acid-N-hydroxysuccinimide) (F127-P(Asp-NHS)), to create a scald dressing. The H2S released by the hydrogel dressing on demand regulates the wound microenvironment by alleviating infection, reducing oxidative stress, and remodeling inflammation, thereby accelerating the healing of full-thickness scalded wounds. This hydrogel dressing for the adaptive release of H2S has great potential in addressing complex scalded wounds associated with infection and chronic inflammation.

Incorporation of essential oils in polymeric films for biomedical applications

Natural and synthetic biodegradable polymers are widely used to obtain more sustainable films with biological, physicochemical, and mechanical properties for biomedical purposes. The incorporation of essential oils (EOs) in polymeric films can optimize the biological activities of these EOs, protect them from degradation, and serve as a prototype for new biotechnological products. This article aims to discuss updates over the last 10 years on incorporating EOs into natural and synthetic biodegradable polymer films for biomedical applications. Chitosan, alginates, cellulose, and proteins such as gelatine, silk, and zein are among the natural polymers most commonly used to prepare biodegradable films for release EOs. In addition to these, the most cited synthetic biodegradable polymers are poly(L-lactide) (PLA), poly(vinyl alcohol) (PVA), and poly(ε-caprolactone) (PCL). The EOs of clove, cinnamon, tea tree, eucalyptus, frankincense, lavender, thyme and oregano incorporated into polymeric films have been the most studied EOs in recent years in the biomedical field. Biomedical applications include antimicrobial activity against pathogenic bacteria and fungi, anticancer activity, potential for tissue engineering and regeneration with scaffolds and wound healing as dressings. Thus, this article reports on the importance of incorporating EOs into biodegradable polymer films, making these systems especially attractive for various biomedical applications.

Chitosan-based films filled with nanoencapsulated essential oil: Physical-chemical characterization and enhanced wound healing activity

The economic burden of chronic wounds, the complexity of the process of tissue repair and the possibility of resistant bacterial infections, have triggered a significant research interest in the application of natural alternative therapies for wound healing. Biomolecules are intrinsically multi-active, as they affect multiple mechanisms involved in tissue repair phenomenon, including immunomodulatory, anti-inflammatory, cell proliferation, extra cellular matrix remodeling and angiogenesis. Chitosan features a unique combination of attributes, including intrinsic hemostatic, antimicrobial, and immunomodulatory properties, that make it an exceptional candidate for wound management, in the development of wound dressings and scaffolds. In this study, we produced nanoemulsions (NE) loaded with SFO, characterized them, and evaluated their tissue repairing properties. Dynamic light scattering (DLS) analysis confirmed the formation of a nanoemulsion with a droplet size of 21.12 ± 2.31 nm and a polydispersity index (PdI) of 0.159, indicating good stability for up to 90 days. To investigate the potential wound healing effects, SFO-loaded NE were applied on male C57BL/6 mice for seven consecutive days, producing a significantly higher wound closure efficiency (p < 0.05) for the group treated with SFO-loaded NE compared to the control group treated with the saline solution. This finding indicates that the SFO-loaded NE exhibits therapeutic properties that effectively promote wound healing in this experimental model. Then, SFO-loaded NE were incorporated into chitosan:polyvinyl alcohol (PVA)-based films. The inclusion of NE into the polymer matrix resulted in increased lipophilicity reflected by the contact angle results, while decreasing moisture absorption, water solubility, and crystallinity. Moreover, FTIR analysis confirmed the formation of new bonds between SFO-NE and the film matrix, which also impacted on porosity properties. Thermal analysis indicated a decrease in the glass transition temperature of the films due to the presence of SFO-NE, suggesting a plasticizing role of NE, confirmed by XRD results, that showed a decrease in the crystallinity of the blend films upon the addition of SFO-NE. AFM images showed no evidence of NE droplet aggregation in the Chitosan:PVA film matrix. Moisture absorption and water content decreased upon incorporation of SFO-loaded NE. Although the inclusion of NE increased hydrophobicity and water contact angle, the values remained within an acceptable range for wound healing applications. Overall, our results emphasize the significant tissue repairing properties of SFO-loaded NE and the potential of Chitosan:PVA films containing nanoencapsulated SFO as effective formulations for wound healing with notable tissue repairing properties.

Eobania vermiculata whole-body muscle extract-loaded chitosan nanoparticles enhanced skin regeneration and decreased pro-inflammatory cytokines in vivo

BACKGROUND

Usually, wounds recover in four to six weeks. Wounds that take longer time than this to heal are referred to as chronic wounds. Impaired healing can be caused by several circumstances like hypoxia, microbial colonization, deficiency of blood flow, reperfusion damage, abnormal cellular reaction and deficiencies in collagen production. Treatment of wounds can be enhanced through systemic injection of the antibacterial drugs and/or other topical applications of medications. However, there are a number of disadvantages to these techniques, including the limited or insufficient medication penetration into the underlying skin tissue and the development of bacterial resistance with repeated antibiotic treatment. One of the more recent treatment options may involve using nanotherapeutics in combination with naturally occurring biological components, such as snail extracts (SE). In this investigation, chitosan nanoparticles (CS NPs) were loaded with an Eobania vermiculata whole-body muscle extract. The safety of the synthesized NPs was investigated in vitro to determine if these NPs might be utilized to treat full-skin induced wounds in vivo.

RESULTS

SEM and TEM images showed uniformly distributed, spherical, smooth prepared CS NPs and snail extract-loaded chitosan nanoparticles (SE-CS NPs) with size ranges of 76-81 and 91-95 nm, respectively. The zeta potential of the synthesized SE-CS NPs was - 24.5 mV, while that of the CS NPs was 25 mV. SE-CS NPs showed a remarkable, in vitro, antioxidant, anti-inflammatory and antimicrobial activities. Successfully, SE-CS NPs (50 mg/kg) reduced the oxidative stress marker (malondialdehyde), reduced inflammation, increased the levels of the antioxidant enzymes (superoxide dismutase and glutathione), and assisted the healing of induced wounds. SE-CS NPs (50 mg/kg) can be recommended to treat induced wounds safely. SE was composed of a collection of several wound healing bioactive components [fatty acids, amino acids, minerals and vitamins) that were loaded on CS NPs.

CONCLUSIONS

The nanostructure enabled bioactive SE components to pass through cell membranes and exhibit their antioxidant and anti-inflammatory actions, accelerating the healing process of wounds. Finally, it is advised to treat rats' wounds with SE-CS NPs.

Development, characterization and evidence of anti-endometriotic activity of Phytocannabinoid-Rich nanoemulsions

During the last decades, the cannabinoid research for therapeutic purposes has been rapidly advancing, with an ever-growing body of evidence of beneficial effects for a wide sort of conditions, including those related to mucosal and epithelial homeostasis, inflammatory processes, immune responses, nociception, and modulating cell differentiation. β-caryophyllene (BCP) is a lipophilic volatile sesquiterpene, known as non-cannabis-derived phytocannabinoid, with documented anti-inflammatory, anti-proliferative and analgesic effects in both in vitro and in vivo models. Copaiba oil (COPA) is an oil-resin, mainly composed of BCP and other lipophilic and volatile components. COPA is reported to show several therapeutic effects, including anti-endometriotic properties and its use is widespread throughout the Amazonian folk medicine. COPA was nanoencapsulated into nanoemulsions (NE), then evaluated regarding the potential for transvaginal drug delivery and providing endometrial stromal cell proliferation in vitro. Transmission electron microscopy (TEM) showed that spherical NE were obtained with COPA concentration that varied from 5 to 7 wt%, while surfactant was maintained at 7.75 wt%. Dynamic light scattering (DLS) measurements showed droplet sizes of 30.03 ± 1.18, 35.47 ± 2.02, 43.98 ± 4.23 and PdI of 0.189, 0.175 and 0.182, respectively, with stability against coalescence and Ostwald ripening during 90 days. Physicochemical characterization results suggest that NE were able to both improve solubility and loading capacity, and increase thermal stability of COPA volatile components. Moreover, they showed slow and sustained release for up to eight hours, following the Higuchi kinetic model. Endometrial stromal cells from non-endometriotic lesions and ectopic endometrium were treated with different concentrations of COPA-loaded NE for 48 h to evaluate its effect on cell viability and morphology. The results suggested significant decrease in cell viability and morphological modifications in concentrations higher than 150 μg/ml of COPA-loaded NE, but not when cells were treated with the vehicle (without COPA). Given the relevance of Copaifera spp. species in folk medicine and their bio economical importance in the Amazon, the development of novel formulations to overcome the technological limitations related to BCP and COPA, is promising. Our results showed that COPA-loaded NE can lead to a novel, uterus-targeting, more effective and promising natural alternative treatment of endometriosis.

Multidrug-Resistant Pathogens in Burn Wound, Prevention, Diagnosis, and Therapeutic Approaches (Conventional Antimicrobials and Nanoparticles)

Multidrug-resistant pathogens are one of the common causes of death in burn patients and have a high risk of nosocomial infections, especially pneumonia, urinary tract infections, and cellulitis. The role of prolonged hospitalization and empirical antibiotics administration in developing multidrug-resistant pathogens is undeniable. In the early days of admitting burn patients, Gram-positive bacteria were the dominant isolates with a more sensitive antibiotic pattern. However, the emergence of Gram-negative bacteria that are more resistant later occurs. Trustworthy guideline administration in burn wards is one of the strategies to prevent multidrug-resistant pathogens. Also, a multidisciplinary therapeutic approach is an effective way to avoid antibiotic resistance that involves infectious disease specialists, pharmacists, and burn surgeons. However, the emerging resistance to conventional antimicrobial approaches (such as systemic antibiotic exposure, traditional wound dressing, and topical antibiotic ointments) among burn patients has challenged the treatment of multidrug-resistant infections, and using nanoparticles is a suitable alternative. In this review article, we will discuss different aspects of multidrug-resistant pathogens in burn wounds, emphasizing the full role of these pathogens in burn wounds and discussing the application of nanotechnology in dealing with them. Also, some advances in various types of nanomaterials, including metallic nanoparticles, liposomes, hydrogels, carbon quantum dots, and solid lipid nanoparticles in burn wound healing, will be explained.

Aloe vera and copaiba oleoresin-loaded chitosan films for wound dressings: microbial permeation, cytotoxicity, and in vivo proof of concept

Chitosan films are commonly used for wound dressing, provided that this polymer has healing, mucoadhesiveness and antimicrobial properties. These properties can be further reinforced by the combination of chitosan with polysaccharides and glycoproteins present in aloe vera, together with copaiba oleoresin's pharmacological activity attributed to sesquiterpenes. In this work, we developed chitosan films containing either aloe vera, copaiba oil or both, by casting technique, and evaluated their microbial permeation, antimicrobial activity, cytotoxicity, and in vivo healing potential in female adult rats. None of the developed chitosan films promoted microbial permeation, while the cytotoxicity in Balb/c 3 T3 clone A31 cell line revealed no toxicity of films produced with 2 % of chitosan and up to 1 % of aloe vera and copaiba oleoresin. Films obtained with either 0.5 % chitosan or 0.5 % copaiba oleoresin induced cell proliferation which anticipate their potential for closure of wound and for the healing process. The in vivo results confirmed that tested films (0.5 % copaiba-loaded chitosan film and 0.5 % aloe vera-loaded chitosan film) were superior to a commercial dressing film. For all tested groups, a fully formed epithelium was seen, while neoformation of vessels seemed to be greater in formulations-treated groups than those treated with the control. Our work confirms the added value of combining chitosan with aloe vera and copaiba oil in the healing process of wounds.

Copaiba essential oil loaded-nanocapsules film as a potential candidate for treating skin disorders: preparation, characterization, and antibacterial properties

Infections have emerged as a novel target in managing skin and mucosa diseases. Bacterial resistance to antimicrobials and biofilm elimination from surfaces remains a challenge. Because polymeric nanocapsules (NC) can increase antimicrobial activity, this study aimed to produce and characterize NC into chitosan films (CSF). Copaiba essential oil (CO) presents antimicrobial activity and was chosen to load NC. In addition, the antibacterial activity was evaluated to obtain a new biodegradable polymeric platform system with the potential to treat topical diseases associated with bacterial infections. The CO-NC produced by nanoprecipitation presented particle size lower than 250 nm, negative charge, and encapsulation efficiency higher than 70 %. Direct incorporation of CO into CSF (CO-CSF) by casting method worsened the film's characteristics. However, incorporating CO-NC into CSF (CO-NC-CSF) avoided these drawbacks demonstrating improved physical, mechanical, morphological, and topographical properties. FTIR results demonstrated possible intermolecular interactions among the polymers and CO. The CO-NC-CSF and CO-CSF presented antibacterial properties against Staphylococcus aureus, and Pseudomonas aeruginosa, especially the formulation containing 1 % of CO. These results indicated that CO-NC-CSF is a promising candidate for treating skin disorders.

The aging analysis of natural rubber-Copaifera oblongifolia extract membranes

Natural rubber (NR), derived from Hevea brasiliensis, has properties for biomedical applications. Several studies indicate that these properties can be amplified when we associate another bioproduct. However, there are no studies of aging aspects of this biomaterial regarding changes in functionality, structure and composition. The objective was to evaluate the aging process of natural rubber membranes - copaiba (NRC) subjected to controlled conditions of time, light and presence of oxygen. The NRC was prepared and stored in the presence or absence of light and vacuum, for periods of 30, 60 and 90 days. Subsequently, the membranes were characterized through the techniques of wettability, infrared spectroscopy, thermal analysis, scanning microscopy and antioxidant activity. The wettability analysis, showed that NRC membranes both in the zero time and in the aging time were hydrophilic. Through thermogravimetric analysis and differential exploratory analysis the membranes remained thermally stable. The scanning electronic microscopy, indicated no morphological alterations during the observed period. After 90 days, the packaged membranes showed satisfactory antioxidant activity. Our results suggest that the membranes were resistant to the storage period, since they maintained their chemical, thermal, morphological and antioxidant characteristics. Hence, it corroborates to use of membranes as a possible curative for biomedical applications.

Conventional and PEGylated Liposomes as Vehicles of Copaifera sabulicola

Traditional medicine uses resin oils extracted from plants of the genus Copaifera for several purposes. Resin oils are being studied to understand and profile their pharmacological properties. The aim of this work was to prepare and to characterize conventional and pegylated liposomes incorporating resin oils or the hexanic extract obtained from Copaifera sabulicola (copaiba) leaves. The cytotoxic effect of these products was also investigated. Conventional and stealth liposomes with copaiba extract showed similar average diameters (around 126 nm), encapsulation efficiencies greater than 75% and were stable for 90 days. A cytotoxicity test was performed on murine glioma cells and the developed liposomes presented antiproliferative action against these cancer cells at the average concentration of 30 μg/mL. Phytochemicals encapsulated in PEGylated liposomes induced greater reduction in the viability of tumor cells. In addition, bioassay-s measured the cytotoxicity of copaiba resin oil (Copaifera sabulicola) in liposomes (conventional and PEGylated), which was also checked against pheochromocytoma PC12 cells. Its safety was verified in normal rat astrocytes. The results indicate that liposomes encapsulating copaiba oil showed cytotoxic activity against the studied tumor strains in a dose-dependent fashion, demonstrating their potential applications as a chemotherapeutic bioactive formulation.

Hyaluronic acid-based nanofibers: Electrospun synthesis and their medical applications; recent developments and future perspective

Hyaluronan is a biodegradable, biopolymer that represents a major part of the extracellular matrix and has the potential to be fabricated in a fibrous form conjugated with other polymers via electrospinning. Unique physicochemical features such as viscoelasticity, conductivity, and biological activity mainly affected by molecular weight attracted the attention of biomedical researchers to utilize hyaluronan for designing novel HA-based nano-devices. Particularly HA-based nanofibers get focused on a diverse range of applications in medical like tissue implants for regeneration of damaged tissue or organ repair, wound dressings, and drug delivery carriers to treat various disorders. Currently, electrospinning represents an effective available method for designing highly porous, 3D, HA-based nanofibers with features similar to that of the extra-cellular matrix making them a promising candidate for designing advanced regenerative medicines. This review highlights the structural and physicochemical features of HA, recently cited protocols in literature for HA production via microbial fermentation with particular focus on electrospun fabrication of HA-based nanofibers and parameters affecting its synthesis, current progress in medical applications of these electrospun HA-based nanofibers, their limitations and future perspective about the potential of these HA-based nanofibers in medical field.

Design and Optimization of a Natural Medicine from Copaifera reticulata Ducke for Skin Wound Care

In this study, we developed a bioadhesive emulsion-filled gel containing a high amount of Copaifera reticulata Ducke oil-resin as a veterinary or human clinical proposal. The phytotherapeutic system had easy preparation, low cost, satisfactory healing ability, and fly repellency, making it a cost-effective clinical strategy for wound care and myiasis prevention. Mechanical, rheological, morphological, and physical stability assessments were performed. The results highlight the crosslinked nature of the gelling agent, with three-dimensional channel networks stabilizing the Copaifera reticulata Ducke oil-resin (CrD-Ore). The emulgel presented antimicrobial activity, satisfactory adhesion, hardness, cohesiveness, and viscosity profiles, ensuring the easy spreading of the formulation. Considering dermatological application, the oscillatory responses showed a viscoelastic performance that ensures emulgel retention at the action site, reducing the dosage frequencies. In Vivo evaluations were performed using a case report to treat ulcerative skin wounds aggravated by myiasis in calves and heifers, which demonstrated healing, anti-inflammatory, and repellent performance for the emulsion-filled gel. The emulgel preparation, which is low in cost, shows promise as a drug for wound therapy.

Cutaneous/Mucocutaneous Leishmaniasis Treatment for Wound Healing: Classical versus New Treatment Approaches

Cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (ML) show clinical spectra that can range from a localized lesion (with a spontaneous healing process) to cases that progress to a generalized systemic disease with a risk of death. The treatment of leishmaniasis is complex since most of the available drugs show high toxicity. The development of an effective topical drug formulation for CL and ML treatment offers advantages as it will improve patient’s compliance to the therapy given the possibility for self-administration, as well as overcoming the first pass metabolism and the high costs of currently available alternatives. The most common dosage forms include solid formulations, such as membranes and semi-solid formulations (e.g., ointments, creams, gels, and pastes). Topical treatment has been used as a new route of administration for conventional drugs against leishmaniasis and its combinations, as well as to exploit new substances. In this review, we discuss the advantages and limitations of using topical drug delivery for the treatment of these two forms of leishmaniasis and the relevance of combining this approach with other pharmaceutical dosage forms. Emphasis will also be given to the use of nanomaterials for site-specific delivery.

Hydrophilic Scaffolds Containing Extracts of Stryphnodendron adstringens and Abarema cochliacarpa for Wound Healing: In Vivo Proofs of Concept

The present work aimed to evaluate the healing effect of hydrophilic polymeric resorbable biomembrane scaffolds containing plant extracts obtained from two different species, both popularly known as Stryphnodendron adstringens or Barbatimão. The hydrogel-based scaffolds were characterized and submitted to biological tests using Wistar rats to evaluate their healing capacity. The wound retraction index and the evaluation of the inflammatory process and tissue collagenization were recorded. The extracts showed antioxidant activity with IC50 between 10 and 20 µg/mL (DPPH assay) and 4–6 mmol Trolox/g (FRAP assay). The extract of Stryphnodendron adstringens (SA) presented gallocatechin, epigallocatechin, and O-methylpigalocatechin, while the extract of Abarema cochliacarpa (AC) presented catechin, dimers of procyanidins, di-O-hydroxide, O-deoxyhexosi-hexoside, and epicatechin. The membranes containing SA extract (GELSA) were more rigid, with a more intense color, but less thick, with a more compact structure and few pores. The membranes containing AC extract (GELAC) presented a mechanical profile like the gelatin membrane (GEL), with greater permeability to water vapor. The GELAC and GELSA membranes showed similar thermal degradation profiles. The wounds treated with the membranes containing the extracts obtained high levels of retraction of the wounds with values around 60% and 80% in three and seven days, respectively. These data indicate that the compounds of both species have promising biological activities in the repair process, showing that the extracts accelerated the healing process due to the lower intensity of the inflammatory reaction and the presence of compounds such as catechin and epigallocatechin.

Copaiba oil and vegetal tannin as functionalizing agents for açai nanofibril films: valorization of forest wastes from Amazonia

The applicability of cellulose nanofibrils (CNFs) has received attention due to their attractive properties. This study proposes the functionalization of açai CNFs with copaiba oil and vegetal tannins to produce films with potential for packaging. Bio-based films were evaluated by vapor permeability, colorimetry, and mechanical strength. CNFs were produced by mechanical fibrillation, from suspensions of bleached açai fibers and commercial eucalipytus pulp. Moreover, copaiba oil and vegetal tannin were added to the CNFs to produce films/nanopapers by casting from both suspensions with concentrations of 1% (based on CNF dry mass). The bulk densities of the eucalyptus CNF films were higher (1.126-1.171 g cm^-3) compared to the açai CNF ones. Films from eucalyptus and açai pulps containing copaiba oil and tannins presented higher Tonset and Tmax, respectively (312 and 370 °C). Films with açaí CNFs functionalized with copaiba oil and tannin showed the lowest permeability value (370 g day^-1 m^-2). Films produced with eucalyptus pulp, and eucalyptus pulp functionalized with copaiba oil highlighted by superior mechanical strength, achieving 133.8 and 121.4 MPa, respectively. The evaluation of colorimetry showed a greater tendency to yellowing for açai films, especially those functionalized with vegetal tannins. Besides the low cost, functionalized vegetal-based nanomaterials could have attractive properties, with potential for application as some kind of packaging, for transporting basic products, such as breads, flours, or products with low moisture content, enabling efficient utilization of forest wastes.

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

Carbon-Based Nanomaterials: Carbon Nanotubes, Graphene and Fullerenes in Control of Burns Infections and Wound Healing

Burn injuries are extremely debilitating, resulting in high morbidity and mortality rates around the world. The risk of infection escalates in correlation with impairment of skin integrity, creating a barrier to healing and possibly leading to sepsis. With its numerous advantages over traditional treatment methods, nanomaterial-based wound healing has immense capability for treating and preventing wound infections. Carbon-based nanomaterials (CNMs) owing to their distinctive physicochemical and biological properties have emerged as promising platform for biomedical applications. Carbon nanotubes, graphene, fullerenes, and their nanocomposites have demonstrated broad antimicrobial activity against invasive bacteria, fungi, and viruses causing burn wound infection. The specific mechanisms that govern the antimicrobial activity of CNMs must be understood in order to ensure the safe and effective incorporation of these structures into biomaterials. However, it is challenging to decouple individual and synergistic contributions of physical, chemical, and electrical effects of CNMs on cells. This review reported on significant advances in the application of CNMs in burn wound infection and wound healing, with brief discussion on the interaction between different families of CNMs and microorganisms to assess antimicrobial performance.

Chitosan Membrane Containing Copaiba Oil (Copaifera spp.) for Skin Wound Treatment

The interaction of copaiba oil in the polymer matrix of chitosan can produce a favorable synergistic effect and potentiate properties. Indeed, the bioactive principles present in copaiba oil have anti-inflammatory and healing action. In the present work, chitosan membranes containing different contents of copaiba oil copaíba (0.1, 0.5, 1.0 and 5.0% (v/v)) were for the first time investigated. The membranes were developed by the casting method and analyzed for their morphology, degree of intumescence, moisture content, contact angle, Scanning Electron Microscope, and X-ray diffractometry. These chitosan/copaiba oil porous membranes disclosed fluid absorption capacity, hydrophilic surface, and moisture. In addition, the results showed that chitosan membranes with the addition of 1.0% (v/v) of copaiba oil presented oil drops with larger diameters, around 123.78 μm. The highest fluid absorption indexes were observed in chitosan membranes containing 0.1 and 0.5% (v/v) of copaiba oil. In addition, the copaiba oil modified the crystalline structure of chitosan. Such characteristics are expected to favor wound treatment. However, biological studies are necessary for the safe use of chitosan/copaiba oil membrane as a biomaterial.

Polymer-Based Nanotherapeutics for Burn Wounds

Burn wounds are complex and intricate injuries that have become a common cause of trauma leading to significant mortality and morbidity every year. Dressings are applied to burn wounds with the aim of promoting wound healing, preventing burn infection and restoring skin function. The dressing protects the injury and contributes to recovery of dermal and epidermal tissues. Polymer-based nanotherapeutics are increasingly being exploited as burn wound dressings. Natural polymers such as cellulose, chitin, alginate, collagen, gelatin and synthetic polymers like poly (lactic-co-glycolic acid), polycaprolactone, polyethylene glycol, and polyvinyl alcohol are being obtained as nanofibers by nanotechnological approaches like electrospinning and have shown wound healing and re-epithelialization properties. Their biocompatibility, biodegradability, sound mechanical properties and unique structures provide optimal microenvironment for cell proliferation, differentiation, and migration contributing to burn wound healing. The polymeric nanofibers mimic collagen fibers present in extracellular matrix and their high porosity and surface area to volume ratio enable increased interaction and sustained release of therapeutics at the site of thermal injury. This review is an attempt to compile all recent advances in the use of polymer-based nanotherapeutics for burn wounds. The various natural and synthetic polymers used have been discussed comprehensively and approaches being employed have been reported. With immense research effort that is currently being invested in this field and development of proper characterization and regulatory framework, future progress in burn treatment is expected to occur. Moreover, appropriate preclinical and clinical research will provide evidence for the great potential that polymer-based nanotherapeutics hold in the management of burn wounds.

Hyaluronic acid nanofiber mats loaded with antimicrobial peptide towards wound dressing applications

Chronic wounds are highly susceptible to bacterial infections. Previously, we loaded a natural antimicrobial peptide of low cost and high safety, ε-polylysine (EPL), into the electrospun nanofiber mat of starch. The mat showed comparable antibacterial activity but markedly better biocompatibility than the commercial silver-containing dressing. To further optimize material property, in this paper, we use hyaluronic acid (HA) to replace starch. Results show that EPL-loaded HA nanofiber mats (OHA-EPL) have suitable water vapor permeability, good biocompatibility and broad-spectrum antibacterial property similar to that of EPL-loaded starch nanofiber mat (Starch-EPL). Differently, the content of EPL in OHA-EPL nanofiber mats increases from 19.2% to 27.9%, the tensile strength rises from 0.3 MPa to 0.6 MPa, the elongation grows from 62.0% to 130.0%, and the fiber degradation and EPL release accelerates. In addition, OHA-EPL can absorb up to 26.3-times exudate, which is much higher than Starch-EPL (15.1 times). Combined with the excellent biological activity of HA, OHA-EPL may produce better therapeutic effects than Starch-EPL.

Nanomaterials in Wound Healing and Infection Control

Wounds continue to be a serious medical concern due to their increasing incidence from injuries, surgery, burns and chronic diseases such as diabetes. Delays in the healing process are influenced by infectious microbes, especially when they are in the biofilm form, which leads to a persistent infection. Biofilms are well known for their increased antibiotic resistance. Therefore, the development of novel wound dressing drug formulations and materials with combined antibacterial, antibiofilm and wound healing properties are required. Nanomaterials (NM) have unique properties due to their size and very large surface area that leads to a wide range of applications. Several NMs have antimicrobial activity combined with wound regeneration features thus give them promising applicability to a variety of wound types. The idea of NM-based antibiotics has been around for a decade at least and there are many recent reviews of the use of nanomaterials as antimicrobials. However, far less attention has been given to exploring if these NMs actually improve wound healing outcomes. In this review, we present an overview of different types of nanomaterials explored specifically for wound healing properties combined with infection control.

Effect of Chitosan and Aloe Vera Extract Concentrations on the Physicochemical Properties of Chitosan Biofilms

Chitosan films have been extensively studied as dressings in formulations for the treatment of chronic wounds. The incorporation of aloe vera (Aloe barbadensis Miller) into chitosan dressings could potentialize the healing process since aloe vera shows several pharmacological activities. This work aimed to evaluate the effect of aloe vera and chitosan concentrations on the physicochemical properties of the developed films. The films were obtained by casting technique and characterized with respect to their color parameters, morphology, barrier and mechanical properties, and thermal analysis. Results showed that the presence of aloe vera modified the films′ color parameters, changed barrier properties, increased fluid handling capacity (FHC), and decreased water-vapor permeability (WVP). The reduced elongation at break resulted in more rigid films. Aloe vera concentration did not significantly change film properties, but the presence of this gel increased the films’ stability at temperatures below 200 °C, showing similar behavior as chitosan films above 400 °C. The results suggest a crosslinking/complexation between chitosan and aloe vera, which combine appropriate physicochemical properties for application as wound dressing materials.

Anti-acetylcholinesterase and toxicity against Artemia salina of chitosan microparticles loaded with essential oils of Cymbopogon flexuosus, Pelargonium x ssp and Copaifera officinalis

Essential oils (EOs) are bioactive compounds with therapeutic potential for use as alternatives or as support to conventional treatments. However, EOs present limitations, such as sensibility to environmental factors, which can be overcome through microencapsulation. The objective of this study was to produce, by spray drying, chitosan microparticles (CMs) loaded with EO of Lemongrass (Cymbopogon flexuosus), Geranium (Pelargonium x ssp) and Copaiba (Copaifera officinalis). Physicochemical and biological characterization of these microparticles showed that CMs presented spherical morphology, had an average size range of 2-3 μm with positive zeta potential (ZP) values, and enhanced thermal stability, compared to free EO. The encapsulation efficiency (EE) ranged from 4.8-58.6%, depending on the oil's properties. In vitro EO release from CMs was determined at different pHs, with 94% release observed in acid media. All microparticles were non-hemolytic at concentrations of up to 0.1 mg·mL^-1. EOs and CMs presented acetylcholinesterase (AChE) inhibition activity (IC 50 ranged from 11.92 to 28.18 μg·mL^-1). Geranium and Copaiba EOs presented higher toxicity against Artemia salina, and greater inhibition of acetylcholinesterase, indicating potential bioactivity for Alzheimer's disease (AD). Our findings demonstrate that CM systems may show promise for the controlled release of these EOs.

Biocompatibility and mechanical properties evaluation of chitosan films containing an N-acylhydrazonic derivative

The N-acylhydrazone subunit is considered a privileged structure in medicinal chemistry for its importance in pharmaceutical research. Also, alternative methods to deliver these molecules have a great pharmaceutical interest. Therefore, the objective of this work was to encapsulate JR19, an N-acyl hydrazone subunit, into chitosan films and evaluate several properties relevant for transdermal delivery, including biocompatibility using in vitro tests. CHI + JR19 film demonstrates greater strength, flexibility, water absorption capacity, low contact angle and higher surface roughness when compared to CHI. Agar diffusion and 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay show the absence of cytotoxicity and the higher cell viability for CHI + JR19 films. Therefore, the addition of JR19 in the system positively influenced mechanical properties and granted better compatibility with biological environments, showing the potential to treat skin inflammation.

Biodegradability in aquatic system of thin materials based on chitosan, PBAT and HDPE polymers: Respirometric and physical-chemical analysis

Biodegradation tests of chitosan (CH), polybutylene adipate terephthalate (PBAT) and high density polyethylene (HDPE) polymers were carried out using the standard OECD 301D guidelines. The results showed that the CH samples biodegraded faster than those of PBAT. Photographs registered exhibited the complete or partial disintegration of the samples, and a more opaque color was observed with the increase of biodegradation. FTIR analysis showed some changes in the intensity of the typical bands of the HDPE sample. The presence of P. nitroreducens bacteria was revealed on the PBAT sample surface by SEM studies. Additionally, a clear increase in elastic modulus (EM) and tensile strength (TS) values were observed in PBAT and HDPE samples on day 3, which decreased significantly at the end of the study. Furthermore, an increase in the crystallinity of the HDPE sample was observed on day 28.

Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO₃ precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430–450 nm in the ultraviolet-visible (UV–Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT–IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm⁻¹. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

New Nanotechnologies for the Treatment and Repair of Skin Burns Infections

Burn wounds are highly debilitating injuries, with significant morbidity and mortality rates worldwide. In association with the damage of the skin integrity, the risk of infection is increased, posing an obstacle to healing and potentially leading to sepsis. Another limitation against healing is associated with antibiotic resistance mainly due to the use of systemic antibiotics for the treatment of localized infections. Nanotechnology has been successful in finding strategies to incorporate antibiotics in nanoparticles for the treatment of local wounds, thereby avoiding the systemic exposure to the drug. This review focuses on the most recent advances on the use of nanoparticles in wound dressing formulations and in tissue engineering for the treatment of burn wound infections.

Effect of Polysaccharides from Bletilla striata on the Healing of Dermal Wounds in Mice

Bletilla striata has been largely used in traditional folk medicine in China as a wound healing agent and to treat gastritis and several other health problems. Some studies have shown that plant polysaccharides may have the ability to promote wound healing. The aim of this work was to evaluate the wound healing activity of the polysaccharide extracted from Bletilla striata. Firstly, a Bletilla striata polysaccharide was extracted by water extraction and alcohol precipitation and characterized by Fourier transform infrared spectroscopy. The Bletilla striata polysaccharide was then tested for cell migration and proliferation using the mouse fibroblast cell line. Then, the Bletilla striata hydrogel was fabricated for acute wound health care of the mouse full-thickness excision. The results showed that the BSP enhanced the proliferation and migration of L929 cells. The superior wound healing capacity of the BSP hydrogel was demonstrated that it significantly accelerated the wound healing process in vivo in full-thickness skin defect wounded models. Compared to the saline group, the BSP hydrogel could accelerate wound healing and promote re-epithelialization and collagen deposition by means of TGF-β/Smad signal pathway activation. Taken together, BSP hydrogel would be a useful pharmaceutic candidate for acute cutaneous wound health care.

Effect of Polysaccharide Sources on the Physicochemical Properties of Bromelain-Chitosan Nanoparticles

Bromelain, a set of proteolytic enzymes potential pharmaceutical applications, was encapsulated in chitosan nanoparticles to enhance enzyme stability, and the effect of different chitosan sources was evaluated. Chitosan types (i.e., low molecular weight chitosan, chitosan oligosaccharide lactate, and chitosan from shrimp shells) produced nanoparticles with different physicochemical properties, however in all cases, particle size and zeta potential decreased, and polydispersity index increased after bromelain addition. Bromelain encapsulation was higher than 84% and 79% for protein content and enzymatic activity, respectively, with low molecular weight chitosan presenting the highest encapsulation efficiency. Nanoparticle suspension was also tested for accelerated stability and rheological behavior. For the chitosan-bromelain nanoparticles, an instability index below 0.3 was recorded and, in general, the loading of bromelain in chitosan nanoparticles decreased the cohesiveness of the final suspension.

Development of Chitosan/Silver Sulfadiazine/Zeolite Composite Films for Wound Dressing

Biopolymeric films with silver sulfadiazine (AgSD) are proposed as an alternative to the occlusive AgSD-containing creams and gauzes, which are commonly used in the treatment of conventional burns. While the recognized cytotoxicity of AgSD has been reported to compromise its use as an antimicrobial drug in pharmaceuticals, this limitation can be overcome by developing sustained-release formulations. Microporous materials as zeolites can be used as drug delivery systems for sustained release of AgSD. The purpose of this work was the development and characterization of chitosan/zeolite composite films to be used as wound dressings. Zeolite was impregnated with AgSD before the production of the composite films. The physicochemical properties of zeolites and the films were evaluated, as well as the antimicrobial activity of the polymeric films and the cytotoxicity of the films in fibroblasts Balb 3T3/c. Impregnated zeolite exhibited changes in FTIR spectra and XRD diffraction patterns, in comparison to non-impregnated composites, which corroborate the results obtained with EDX-SEM. The pure chitosan film was compact and without noticeable defects and macropores, while the film with zeolite was opaquer, more rigid, and efficient against Candida albicans and some gram-negative bacteria. The safety evaluation showed that although the AgSD films present cytotoxicity, they could be used in a concentration-dependent fashion.