Enhancement of curcumin wound healing ability by complexation with 2-hydroxypropyl-γ-cyclodextrin in sacran hydrogel film

Technological Interventions Enhancing Curcumin Bioavailability in Wound-Healing Therapeutics

Wound healing has been a challenge in the medical field. Tremendous research has been carried out to expedite wound healing by fabricating various formulations, some of which are now commercially available. However, owing to their natural source, people have been attracted to advanced formulations with herbal components. Among various herbs, curcumin has been the center of attraction from ancient times for its healing properties due to its multiple therapeutic effects, including antioxidant, antimicrobial, anti-inflammatory, anticarcinogenic, neuroprotective, and radioprotective properties. However, curcumin has a low water solubility and rapidly degrades into inactive metabolites, which limits its therapeutic efficacy. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, and keep its bioavailability and effectiveness. Different formulations with curcumin have been synthesized, and exist in the form of various synthetic and natural materials, including nanoparticles, hydrogels, scaffolds, films, fibers, and nanoemulgels, improving its bioavailability dramatically. This review discusses the advances in different types of curcumin-based formulations used in wound healing in recent times, concentrating on its mechanisms of action and discussing the updates on its application at several stages of the wound healing process. Impact statement Curcumin is a herbal compound extracted from turmeric root and has been used since time immemorial for its health benefits including wound healing. In clinical formulations, curcumin shows low bioavailability, which mainly stems from the way it is delivered in the body. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, while maintaining its bioavailability and therapeutic efficacy. This review offers an overview of the advanced technological interventions through tissue engineering approaches to efficiently utilize curcumin in different types of wound healing applications.

Antioxidant Hydrogels: Antioxidant Mechanisms, Design Strategies, and Applications in the Treatment of Oxidative Stress-Related Diseases

Oxidative stress is a biochemical process that disrupts the redox balance due to an excess of oxidized substances within the cell. Oxidative stress is closely associated with a multitude of diseases and health issues, including cancer, diabetes, cardiovascular diseases, neurodegenerative disorders, inflammatory conditions, and aging. Therefore, the developing of antioxidant treatment strategies has emerged as a pivotal area of medical research. Hydrogels have garnered considerable attention due to their exceptional biocompatibility, adjustable physicochemical properties, and capabilities for drug delivery. Numerous antioxidant hydrogels have been developed and proven effective in alleviating oxidative stress. In the pursuit of more effective treatments for oxidative stress-related diseases, there is an urgent need for advanced strategies for the fabrication of multifunctional antioxidant hydrogels. Consequently, the authors' focus will be on hydrogels that possess exceptional reactive oxygen species and reactive nitrogen species scavenging capabilities, and their role in oxidative stress therapy will be evaluated. Herein, the antioxidant mechanisms and the design strategies of antioxidant hydrogels and their applications in oxidative stress-related diseases are discussed systematically in order to provide critical insights for further advancements in the field.

Transparent silk fibroin film-facilitated infected-wound healing through antibacterial, improved fibroblast adhesion and immune modulation

The clinical application of regenerated silk fibroin (RSF) films for wound treatment is restricted by its undesirable mechanical properties and lack of antibacterial activity. Herein, different pluronic polymers were introduced to optimize their mechanical properties and the RSF film with 2.5% pluronic F127 (RSFPF127) stood out to address the above issues owing to its satisfactory mechanical properties, hydrophilicity, and transmittance. Diverse antibacterial agents (curcumin, Ag nanoparticles, and antimicrobial peptide KR-12) were separately encapsulated in RSFPF127 to endow it with antibacterial activity. In vitro experiments revealed that the medicated RSFPF127 could persistently release drugs and had desirable bioactivities toward killing bacteria, promoting fibroblast adhesion, and modulating macrophage polarization. In vivo experiments revealed that medicated RSFPF127 not only eradicated methicillin-resistant Staphylococcus aureus in the wound area and inhibited inflammatory responses, but also facilitated angiogenesis and re-epithelialization, regardless of the types of antibacterial agents, thus accelerating the recovery of infected wounds. These results demonstrate that RSFPF127 is an ideal matrix platform to load different types of drugs for application as wound dressings.

Smart and versatile biomaterials for cutaneous wound healing

The global increase of cutaneous wounds imposes huge health and financial burdens on patients and society. Despite improved wound healing outcomes, conventional wound dressings are far from ideal, owing to the complex healing process. Smart wound dressings, which are sensitive to or interact with changes in wound condition or environment, have been proposed as appealing therapeutic platforms to effectively facilitate wound healing. In this review, the wound healing processes and features of existing biomaterials are firstly introduced, followed by summarizing the mechanisms of smart responsive materials. Afterwards, recent advances and designs in smart and versatile materials of extensive applications for cutaneous wound healing were submarined. Finally, clinical progresses, challenges and future perspectives of the smart wound dressing are discussed. Overall, by mapping the composition and intrinsic structure of smart responsive materials to their individual needs of cutaneous wounds, with particular attention to the responsive mechanisms, this review is promising to advance further progress in designing smart responsive materials for wounds and drive clinical translation.

Cyclodextrins for the Delivery of Bioactive Compounds from Natural Sources: Medicinal, Food and Cosmetics Applications

Cyclodextrins have gained significant and established attention as versatile carriers for the delivery of bioactive compounds derived from natural sources in various applications, including medicine, food and cosmetics. Their toroidal structure and hydrophobic cavity render them ideal candidates for encapsulating and solubilizing hydrophobic and poorly soluble compounds. Most medicinal, food and cosmetic ingredients share the challenges of hydrophobicity and degradation that can be effectively addressed by various cyclodextrin types. Though not new or novel-their first applications appeared in the market in the 1970s-their versatility has inspired numerous developments, either on the academic or industrial level. This review article provides an overview of the ever-growing applications of cyclodextrins in the delivery of bioactive compounds from natural sources and their potential application benefits.

Next-Generation Hydrogels as Biomaterials for Biomedical Applications: Exploring the Role of Curcumin

Since the first report on the pharmacological activity of curcumin in 1949, enormous amounts of research have reported diverse activities for this natural polyphenol found in the dietary spice turmeric. However, curcumin has not yet been used for human application as an approved drug. The clinical translation of curcumin has been hampered due to its low solubility and bioavailability. The improvement in bioavailability and solubility of curcumin can be achieved by its formulation using drug delivery systems. Hydrogels with their biocompatibility and low toxicity effects have shown a substantial impact on the successful formulation of hydrophobic drugs for human clinical trials. This review focuses on hydrogel-based delivery systems for curcumin and describes its applications as anti-cancer as well as wound healing agents.

Cyclodextrin regulated natural polysaccharide hydrogels for biomedical applications-a review

Cyclodextrin and its derivative (CDs) are natural building blocks for linking with other components to afford functional biomaterials. Hydrogels are polymer network systems that can form hydrophilic three-dimensional network structures through different cross-linking methods and are developing as potential materials in biomedical applications. Natural polysaccharide hydrogels (NPHs) are widely adopted in biomedical field with good biocompatibility, biodegradability, low cytotoxicity, and versatility in emulating natural tissue properties. Compared with conventional NPHs, CD regulated natural polysaccharide hydrogels (CD-NPHs) maintain good biocompatibility, while improving poor mechanical qualities and unpredictable gelation times. Recently, there has been increasing and considerable usage of CD-NPHs while there is still no review comprehensively introducing their construction, classification, and application of these hydrogels from the material point of view regarding biomedical fields. To draw a complete picture of the current and future development of CD-NPHs, we systematically overview the classification of CD-NPHs, and provide a holistic view on the role of CD-NPHs in different biomedical fields, especially in drug delivery, wound dressing, cell encapsulation, and tissue engineering. Moreover, the current challenges and prospects of CD-NPHs are discussed rationally, providing an insight into developing vibrant fields of CD-NPHs-based biomedicine, and facilitating their translation from bench to clinical medicine.

Curcumin Release from Biomaterials for Enhanced Tissue Regeneration Following Injury or Disease

Curcumin, a bioactive phenol derived from turmeric, is an antioxidant, anti-inflammatory, and antibacterial molecule. Although curcumin exhibits beneficial effects in its innate form, it is highly hydrophobic, which leads to poor water solubility and, consequently, low bioavailability. The lack of bioavailability limits curcumin's effectiveness as a treatment and restricts its use in clinical applications. Furthermore, to achieve beneficial, clinically relevant results, high doses of curcumin are required for systemic administration. Many researchers have utilized biomaterial carriers, including electrospun fibers, nanoparticles, hydrogels, and composite scaffolds, to overcome curcumin's principle therapeutic limitation of low bioavailability. By using biomaterials to deliver curcumin directly to injury sites, researchers have harnessed the beneficial natural properties of curcumin while providing scaffolding to support tissue regeneration. This review will provide an in-depth overview of the literature that utilizes biomaterial delivery of curcumin for tissue regeneration in injury and disease models.

Current Techniques of Water Solubility Improvement for Antioxidant Compounds and Their Correlation with Its Activity: Molecular Pharmaceutics

The aqueous solubility of a drug is important in the oral formulation because the drug can be absorbed from intestinal sites after being dissolved in the gastrointestinal fluid, leading to its bioavailability. Almost 80% of active pharmaceutical ingredients are poorly water-soluble, including antioxidant compounds. This makes antioxidant activity inefficient in preventing disease, particularly for orally administered formulations. Although several investigations have been carried out to improve the solubility of antioxidant compounds, there is still limited research fully discussing the subject. Therefore, this study aimed to provide an overview and discussion of the issues related to the methods that have been used to improve the solubility and activity of antioxidant compounds. Articles were found using the keywords "antioxidant" and "water solubility improvement" in the Scopus, PubMed, and Google Scholar databases. The selected articles were published within the last five years to ensure all information was up-to-date with the same objectives. The most popular methods of the strategies employed were solid dispersion, co-amorphous, and nanoparticle drug delivery systems, which were used to enhance the solubility of antioxidant compounds. These investigations produced impressive results, with a detailed discussion of the mechanism of improvement in the solubility and antioxidant activity of the compounds developed. This review shows that the strategies used to increase the solubility of antioxidant compounds successfully improved their antioxidant activity with enhanced free radical scavenging abilities.

Alginate/Chitosan-Based Hydrogel Film Containing α-Mangostin for Recurrent Aphthous Stomatitis Therapy in Rats

Recurrent aphthous stomatitis (RAS) is a prevalent clinical disorder that causes mouth ulcers. Furthermore, corticosteroid treatment has been widely utilized for RAS therapy; however, it has side effects on the oral mucosa that limit its application. This study aimed to develop a novel RAS therapy with the natural ingredient α-mangostin, delivered by alginate and chitosan polymers-based hydrogel film (α-M Alg/Chi-HF). To prepare α-M Alg/Chi-HF, the solvent evaporation and casting methods were used, then characterized by using SEM, FTIR, and XRD. Based on the characterization studies, the α-M in α-M/EtOH Alg/Chi-HF with ethanol (EtOH) was found to be more homogenous compared to α-M in Alg/Chi-HF with distilled water (H2O) as a casting solvent. The in vitro viability study using NIH3T3 cells showed 100% viability of α-M Alg/Chi-HF (EtOH) and Alg/Chi-HF after 24 h incubation, indicating well tolerability of these hydrogel films. Interestingly, the in vivo studies using male white rats (Rattus norvegicus Berkenhout) proved that α-M/EtOH Alg/Chi-HF with a recovery of 81.47 ± 0.09% in seven days significantly more effective RAS therapy compared to control. These results suggest that α-M/EtOH Alg/Chi-HF has the potential as an alternative for RAS therapy.

Cytotoxicity Enhancement in MCF-7 Breast Cancer Cells with Depolymerized Chitosan Delivery of α-Mangostin

The application of α-mangostin (AMG) in breast cancer research has wide intentions. Chitosan-based nanoparticles (CSNPs) have attractive prospects for developing anticancer drugs, especially in their high flexibility for modification to enhance their anticancer action. This research aimed to study the impact of depolymerized chitosan (CS) on the cytotoxicity enhancement of AMG in MCF-7 breast cancer cells. CSNPs effectivity depends on size, shape, crystallinity degree, and charge surface. Modifying CS molecular weight (MW) is expected to influence CSNPs’ characteristics, impacting size, shape, crystallinity degree, and charge surface. CSNPs are developed using the method of ionic gelation with sodium tripolyphosphate (TPP) as a crosslinker and spray pyrolysis procedure. Nanoparticles’ (NPs) sizes vary from 205.3 ± 81 nm to 450.9 ± 235 nm, ZP charges range from +10.56 mV to +51.56 mV, and entrapment efficiency from 85.35% to 90.45%. The morphology of NPs are all the same spherical forms. In vitro release studies confirmed that AMG–Chitosan–High Molecular Weight (AMG–CS–HMW) and AMG–Chitosan–Low Molecular Weight (AMG–CS–LMW) had a sustained-release system profile. MW has a great influence on surface, drug release, and cytotoxicity enhancement of AMG in CSNPs to MCF-7 cancer cells. The preparations AMG–CS–HMW and AMG–CS–LMW NPs considerably enhanced the cytotoxicity of MCF-7 cells with IC₅₀ values of 5.90 ± 0.08 µg/mL and 4.90 ± 0.16 µg/mL, respectively, as compared with the non-nano particle formulation with an IC₅₀ of 8.47 ± 0.29 µg/mL. These findings suggest that CSNPs can enhance the physicochemical characteristics and cytotoxicity of AMG in breast cancer treatment.

Lasered Graphene Microheaters Modified with Phase-Change Composites: New Approach to Smart Patch Drug Delivery

The combination of paraffin wax and O,O′-bis(2-aminopropyl) polypropylene glycol–block–polyethylene glycol–block–polypropylene glycol was used as a phase-change material (PCM) for the controlled delivery of curcumin. The PCM was combined with a graphene-based heater derived from the laser scribing of polyimide film. This assembly provides a new approach to a smart patch through which release can be electronically controlled, allowing repetitive dosing. Rather than relying on passive diffusion, delivery is induced and terminated through the controlled heating of the PCM with transfer only occurring when the PCM transitions from solid to liquid. The material properties of the device and release characteristics of the strategy under repetitive dosing are critically assessed. The delivery yield of curcumin was found to be 3.5 µg (4.5 µg/cm²) per 3 min thermal cycle.

Complexation of phytochemicals with cyclodextrins and their derivatives- an update

Bioactive phytochemicals from natural source have gained tremendous interest over several decades due to their wide and diverse therapeutic activities playing key role as functional food supplements, pharmaceutical and nutraceutical products. Nevertheless, their application as therapeutically active moieties and formulation into novel drug delivery systems are hindered due to major drawbacks such as poor solubility, bioavailability and dissolution rate and instability contributing to reduction in bioactivity. These drawbacks can be effectively overcome by their complexation with different cyclodextrins. Present article discusses complexation of phytochemicals varying from flavonoids, phenolics, triterpenes, and tropolone with different natural and synthetic cyclodextrins. Moreover, the article summarizes complexation methods, complexation efficiency, stability, stability constants and enhancement in rate and extent of dissolution, bioavailability, solubility, in vivo and in vitro activities of reported complexed phytochemicals. Additionally, the article presents update of published patent details comprising of complexed phytochemicals of therapeutic significance. Thus, phytochemical cyclodextrin complexes have tremendous potential for transformation into drug delivery systems as substantiated by significant outcome of research findings.

Strategies for Biomaterial-Based Spinal Cord Injury Repair via the TLR4-NF-κB Signaling Pathway

The repair and motor functional recovery after spinal cord injury (SCI) has remained a clinical challenge. Injury-induced gliosis and inflammation lead to a physical barrier and an extremely inhibitory microenvironment, which in turn hinders the recovery of SCI. TLR4-NF-κB is a classic implant-related innate immunomodulation signaling pathway and part of numerous biomaterial-based treatment strategies for SCI. Numerous experimental studies have demonstrated that the regulation of TLR4-NF-κB signaling pathway plays an important role in the alleviation of inflammatory responses, the modulation of autophagy, apoptosis and ferroptosis, and the enhancement of anti-oxidative effect post-SCI. An increasing number of novel biomaterials have been fabricated as scaffolds and carriers, loaded with phytochemicals and drugs, to inhibit the progression of SCI through regulation of TLR4-NF-κB. This review summarizes the empirical strategies for the recovery after SCI through individual or composite biomaterials that mediate the TLR4-NF-κB signaling pathway.

Cellulose: A Fascinating Biopolymer for Hydrogel Synthesis

The growing environmental concerns and increasing demands for eco-friendly materials have obliged researchers worldwide to explore naturally occurring biopolymers for various applications. Cellulose is a non-exhaustible polysaccharide biopolymer available almost...

Functional Hydrogels as Wound Dressing to Enhance Wound Healing

Hydrogels, due to their excellent biochemical and mechnical property, have shown attractive advantages in the field of wound dressings. However, a comprehensive review of the functional hydrogel as a wound dressing is still lacking. This work first summarizes the skin wound healing process and relates evaluation parameters and then reviews the advanced functions of hydrogel dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and anti-oxidation, substance delivery, self-healing, stimulus response, conductivity, and the recently emerged wound monitoring feature, and the strategies adopted to achieve these functions are all classified and discussed. Furthermore, applications of hydrogel wound dressing for the treatment of different types of wounds such as incisional wound and the excisional wound are summarized. Chronic wounds are also mentioned, and the focus of attention on infected wounds, burn wounds, and diabetic wounds is discussed. Finally, the future directions of hydrogel wound dressings for wound healing are further proposed.

A Comprehensive Review on Ulvan Based Hydrogel and Its Biomedical Applications

Ulvan is a natural sulfated polysaccharide obtained from marine green algae composed of 3-sulfated rhamnoglucuronan as the main component. It has a unique chemical structure that rich of L-rhamnosa, D-glucuronic acid, and L-iduronic acid. Ulvan has a similar structure to glycosaminoglycans (GAGs) in mammals including chondroitin sulfate, dermatan sulfate, and heparan sulfate that has broad range applications for many years. Here, we provide an overview of ulvan based hydrogels for biomedical applications. Hydrogels are one of ulvan advances in polymer science for application in drug delivery, tissue engineering, and wound healing. This review presented an overview about functional information of ulvan based hydrogels and the promising potential in biomedicals collected from published papers in Scopus, PubMed, and Google Scholar. Other important aspects concerning properties, hydrogel-forming mechanisms, and ulvan based hydrogel developments were reported as well. As conclusion, ulvan showed interesting properties in forming hydrogels and promising advances in biomedical applications.

Curcumin-loaded sandwich-like nanofibrous membrane prepared by electrospinning technology as wound dressing for accelerate wound healing

Wound healing is a complicated process constituted of four successive physiological stages involving wound bleeding, inflammatory response, cell proliferation and tissue remodeling. During this period, bacteria can easily infect the wound. Therefore, we prepared a novel curcumin-loaded sandwich-like nanofibrous membrane (CSNM) using sequential electrospinning for the hemostasis, antibacterial and accelerate wound healing. The morphology of the nanofibrous membrane was analyzed by SEM. In addition, the water absorption capacity, water vapor transmission rate, water contact-angle, and in vitro drug release were all tested. Then in vitro and in vivo hemostatic experiments demonstrated that CSNM has a good hemostatic effect. Antioxidant effect was assessed by the DPPH radical scavenging method and CSNM presented a high antioxidant activity. Additionally, CSNM demonstrated excellent antibacterial activity by the disk diffusion method. Furthermore, the rat dorsal skin defects model revealed that the CSNM distinctly induced the granulation tissue grew, collagen deposition and epithelial tissue remodeling. Meanwhile, the results of the immunohistochemical staining showed that the CSNM can facilitate the expression of CD31 and TGF-β in the early stage of the wound, thereby accelerating wound healing. In general, this study proved that the multifunctional CSNM has great potential as wound dressing in wound healing.

The Use of Megamolecular Polysaccharide Sacran in Food and Biomedical Applications

Natural polymer is a frequently used polymer in various food applications and pharmaceutical formulations due to its benefits and its biocompatibility compared to synthetic polymers. One of the natural polymer groups (i.e., polysaccharide) does not only function as an additive in pharmaceutical preparations, but also as an active ingredient with pharmacological effects. In addition, several natural polymers offer potential distinct applications in gene delivery and genetic engineering. However, some of these polymers have drawbacks, such as their lack of water retention and elasticity. Sacran, one of the high-molecular-weight natural polysaccharides (megamolecular polysaccharides) derived from Aphanothece sacrum (A. sacrum), has good water retention and elasticity. Historically, sacran has been used as a dietary food. Moreover, sacran can be applied in biomedical fields as an active material, excipient, and genetic engineering material. This article discusses the characteristics, extraction, isolation procedures, and the use of sacran in food and biomedical applications.

Therapeutic effect of curcumin on oral diseases: A literature review

Curcumin (diferuloylmethane) is a polyphenol compound extracted from the rhizome of the plant Curcuma longa. It has the feature of being a yellow or orange pigment with a variety of biological properties, including anti-inflammation, antioxidation, anti-tumor, anti-bacteria, anti-fungus, and wound healing. Previous studies have reported the role of curcumin in treating different inflammatory diseases and tumors in vitro and in vivo. Recently, it has been demonstrated that curcumin has therapeutic benefits in oral mucosal diseases, periodontal diseases, and mouth neoplasms. In this review, we will focus on the therapeutic effects of curcumin on oral diseases.

Free-Standing Photocrosslinked Protein Polymer Hydrogels for Sustained Drug Release

The fabrication of protein hydrogels consisting of different properties and functional motifs is critical in the development of protein-based materials for biomedical applications. Here, we report the design and characterization of a triblock protein polymer, CEC, composed of two different self-assembling domains derived from elastin protein (E) and coiled-coil protein (C), photopolymerized with a NHS-diazirine (D) crosslinker into a CEC-D hydrogel. The optimal photocrosslinker concentration and exposure time is determined to fabricate a free-standing hydrogel. Upon increasing the concentration of the CEC-D monomer and environmental temperature, the CEC-D hydrogel's conformation decreases in helical content from 58.0% to 44.8% and increases in β-content from 25.9% to 38.1%. These gels experience 55 ± 6% protein erosion from the free-standing gel in 13 days as the gel films gradually decrease in size. The swelling ratio of 12 ± 1% denotes that the gel has a swelling ability comparable to other protein hydrogels. These photocrosslinked CEC-D hydrogels can be employed for drug delivery with high encapsulation and 14 ± 2% release of curcumin into the supernatant in a week long study. Overall, the photocrosslinked CEC-D hydrogels exhibit stability, swelling ability, and sustained release of drug.

In vitro and in vivo evaluation of gellan gum hydrogel films: Assessing the co impact of therapeutic oils and ofloxacin on wound healing

Herein, we report co-encapsulation of ofloxacin with tea tree or lavender oil in gellan gum based hydrogel films by solvent casting ionotropic gelation method as wound dressing. Prepared films were transparent, flexible, and displayed antioxidant activity with superior antibacterial response against common inhabitants of wound i.e. gram positive and negative bacteria. Solid-state characterization of optimized formulation (OL3 and OT3) revealed successful incorporation of drug and oils in hydrogel structure without any noticeable interaction. In vitro release studies showed an initial burst release but remaining portion released in controlled manner over 48 h from the films and furthermore, presence of oils did not affected the ofloxacin release. Optimized formulation containing ofloxacin and 25% w/w lavender/tea tree oil showed 98% wound contraction in rats after ten days of treatment. Histological images displayed completely healed epidermis. Taken together, our prepared hydrogel films demonstrated favorable features with appreciable antibacterial, wound healing activity and could be useful for the treatment of full thickness wounds.

Polymer-Based Materials Loaded with Curcumin for Wound Healing Applications

Some of the currently used wound dressings have interesting features such as excellent porosity, good water-absorbing capacity, moderate water vapor transmission rate, high drug loading efficiency, and good capability to provide a moist environment, but they are limited in terms of antimicrobial properties. Their inability to protect the wound from microbial invasion results in wound exposure to microbial infections, resulting in a delayed wound healing process. Furthermore, some wound dressings are loaded with synthetic antibiotics that can cause adverse side effects on the patients. Natural-based compounds exhibit unique features such as good biocompatibility, reduced toxicity, etc. Curcumin, one such natural-based compound, has demonstrated several biological activities such as anticancer, antibacterial and antioxidant properties. Its good antibacterial and antioxidant activity make it beneficial for the treatment of wounds. Several researchers have developed different types of polymer-based wound dressings which were loaded with curcumin. These wound dressings displayed excellent features such as good biocompatibility, induction of skin regeneration, accelerated wound healing processes and excellent antioxidant and antibacterial activity. This review will be focused on the in vitro and in vivo therapeutic outcomes of wound dressings loaded with curcumin.

Enhancement of α-Mangostin Wound Healing Ability by Complexation with 2-Hydroxypropyl-β-Cyclodextrin in Hydrogel Formulation

α-Mangostin (α-M), one of the active compounds in Garcinia mangostana peel, has been effectively used in wound healing. However, its poor solubility in aqueous solution causes low bioavailability for skin ulcers, hindering its application in wound healing. The aim of this study was to improve the solubility of α-M through complex formation with 2-hydroxypropyl-β-cyclodextrin (α-M/HP-β-CD CX) and to evaluate the healing activity of the complex. The α-M/HP-β-CD CX was incorporated in a sodium carboxymethylcellulose hydrogel (α-M/HP-β-CD CX HG), and the in vivo healing activity was examined in mice. Evaluation of α-M/HP-β-CD CX HG, including organoleptic evaluation, homogeneity, pH, spreadability, swelling ratio, consistency, scanning electron microscopy (SEM), and in vitro drug release, was carried out. The complex formation of α-M/HP-β-CD CX was confirmed by FTIR and PXRD analysis. The solubility of the α-M/HP-β-CD CX in water linearly increased about 11.7-fold compared to α-M alone, and by 3.5-fold compared to the α-M/HP-β-CD physical mixture (α-M/HP-β-CD CX PM). The α-M/HP-β-CD CX HG was homogenous, the pH was found to be in the neutral range, the spread area was 5 cm, and the consistency was stable until 14 days. SEM analysis showed that α-M/HP-β-CD CX HG surged due to the porous structure of the HG. In addition, in vitro release of α-M from α-M/HP-β-CD CX HG was considerably increased compared to α-M/HP-β-CD PM HG and α-M HG. Notably, in vivo evaluation in mice showed that α-M/HP-β-CD CX HG significantly accelerated the wound healing ability compared to other HGs. Thus, α-M/HP-β-CD CX HG has potential as a new formulation of α-M for wound healing therapy.

Epidermal growth factor in sacran hydrogel film accelerates fibroblast migration

Epidermal growth factor (EGF) accelerates epidermal regeneration, and it is widely studied as a wound-healing agent. However, the special carrier for the topical administration of EGF is urgently needed to deliver EGF on the wound site. In a preceding study, sacran hydrogel film (Sac-HF) showed a possible use as a dressing material for wound healing, as well as a good capability as a drug carrier. In the current study, we prepared Sac-HF containing EGF (Sac/EGF-HF) and then characterized their physicochemical properties, including thickness, swelling ratio, degradability, tensile strength, and morphology. In addition, we have also conducted thermal and crystallography studies using differential scanning calorimetry (DSC) and X-ray diffraction, respectively. Furthermore, we investigated the in vitro influence of Sac/EGF-HF on cell migration using a fibroblast cell line. Morphology study confirmed that the casting method used for the film preparation resulted in a homogeneous film of Sac/EGF-HF. Furthermore, EGF significantly increased the thickness, tensile strength, and degradability of Sac/EGF-HF compared to Sac-HF. Sac/EGF-HF had a lower swelling ability compared to Sac-HF; this result corroborated the tensile strength result. Interestingly, X-ray diffraction and DSC results showed that Sac/EGF-HF had an amorphous shape. The in vitro studies revealed that Sac/EGF-HF induced the fibroblast migration activity. These results conclude that Sac/EGF-HF has the potential properties of HF for biomedical applications.

Ulmus parvifolia Accelerates Skin Wound Healing by Regulating the Expression of MMPs and TGF-β

Ulmus parvifolia is one of the medicinal plants used traditionally for treatment of wounds. We intended to investigate the wound healing effect of the powder of Ulmus parvifolia (UP) root bark in a mouse wound healing model. We also determined the mechanisms of effects of U. parvifolia in skin and skin wound healing effects using a keratinocyte model. Animal experiments showed that the wound lesions in the mice decreased with 200 mesh U. parvifolia root bark powder and were significantly reduced with treatment by UP, compared with those treated with Ulmus macrocarpa (UM). Results from in vitro experiments also revealed that UP extract promoted the migration of human skin keratinocytes. UP powder treatment upregulated the expression of the matrix metalloproteinase-2 and -9 protein and significantly increased transforming growth factor (TGF)-β levels. We confirmed that topical administration of the bark powder exerted a significant effect on skin wound healing by upregulating the expression of MMP and transforming growth factor-β. Our study suggests that U. parvifolia may be a potential candidate for skin wound healing including epidermal skin rejuvenation.

α-Mangostin Hydrogel Film Based Chitosan–Alginate for Recurrent Aphthous Stomatitis

Many antiseptic drugs, local anaesthetics, and corticosteroids have been used for effective therapy of recurrent aphthous stomatitis (RAS). However, these drugs have harmful side effects. α-mangostin (α-M), a main compound of mangosteen (Garcinia mangostana L.) peel, has been known as a wound healing agent. In addition, hydrogel film as dressings designed to separate mucosal lesions from the oral environment, and improve the effectiveness of RAS therapy. The purpose of this study was to develop α-M hydrogel film based chitosan–alginate (ChAlg/α-M HF) for RAS. The in silico study by Discovery studio visualizer and AutoDock confirmed that hydrogen bonding between Ch, Alg, and α-M occurred. The results of physicochemical characterizations by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) indicated that the ChAlg/α-M HF had a lower crystalline form compared to pure α-M. In addition, ChAlg/α-M HF significantly improved the swelling ratio and tensile strength compared to that of ChAlg HF. Moreover, the existence of Alg increased the degradability of Ch, and closely related to the release of α-M from ChAlg HF. The in vitro release study confirmed that the release of α-M from ChAlg/α-M HF was the Fickian diffusion model. Finally, the mucoadhesive study revealed that ChAlg/α-M HF had a good mucoadhesive property. These results suggest that hydrogel film-based chitosan–alginate have the potential as carriers of α-M for RAS therapy.

Sacran Hydrogel Film Containing Keratinocyte Growth Factor Accelerates Wound Healing by Stimulating Fibroblast Migration and Re-epithelization

Regenerative therapy with keratinocyte growth factor (KGF) is a novel therapeutic approach for treatment of chronic wounds. However, KGF cannot be used directly to the wound site due to its physicochemical instability. In previous study, sacran, a natural megamolecular polysaccharide, showed potential properties as a biomaterial for hydrogel film in wound healing. In this study, we fabricated sacran hydrogel film containing KGF (Sac/KGF-HF) and evaluated the effects of Sac/KGF-HF on fibroblasts migration and re-epithelialization process. We successfully prepared a homogenous and -amorphous Sac/KGF-HF by a casting method. In addition, Sac/KGF-HF had a high swelling ratio and flexibility. Sac/KGF-HF promoted a migration process of NIH3T3 cells and improved wound healing ability in mice with a percentage of wound closure reaching 90.4% at 9 d. Interestingly, the addition of KGF in Sac-HF considerably increased the number of epithelial cells compared to control, which is important in the re-epithelialization process. It could be concluded that KGF in Sac-HF has the potential for promoting Sac-HF abilities in wound healing process.

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

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

Micropatterned Cell Orientation of Cyanobacterial Liquid-Crystalline Hydrogels

Control of cell extension direction is crucial for the regeneration of tissues, which are generally composed of oriented molecules. The scaffolds of highly oriented liquid crystalline polymer chains were fabricated by casting cyanobacterial mega-saccharides, sacran, on parallel-aligned micrometer bars of polystyrene (PS). Polarized microscopy revealed that the orientation was in transverse direction to the longitudinal axes of the PS bars. Swelling behavior of the micropatterned hydrogels was dependent on the distance between the PS bars. The mechanical properties of these scaffolds were dependent on the structural orientation; additionally, the Young's moduli in the transverse direction were higher than those in the parallel direction to the major axes of the PS bars. Further, fibroblast L929 cells were cultivated on the oriented scaffolds to be aligned along the orientation axis. L929 cells cultured on these scaffolds exhibited uniaxial elongation.

[Potential Use of Sacran Hydrogels as Wound Dressing Material]

　A wound dressing is one of the essential approaches to prevent further harm to cutaneous wounds as well as to promote wound healing. Therefore, to achieve ideal wound healing, the development of advanced dressing materials is necessary. Sacran, a novel megamolecular polysaccharide derived from the cyanobacterium Aphanothece sacrum, has a very high molecular weight that exceeds 10⁷ g/mol and water-superabsorbent capacity. Recently, we demonstrated that sacran exerts anti-inflammatory activity by ameliorating the skin barrier function in patients with atopic dermatitis. In this study, to develop and characterize sacran hydrogel films (Sac-HGFs) for wound dressing materials, we prepared a physically crosslinked-Sac-HGFs, and evaluated their physicochemical properties, cytotoxicity, skin hydration and wound healing ability. Additionally, we encapsulated curcumin, as a model drug for wound healing, into Sac-HGFs by complexation with 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CyD), and investigated their potential for wound dressing application. Sac-HGF has potentially good properties for wound dressing application, due to not only the moisturizing effect but also the anti-inflammatory effect of sacran. Additionally, Sac-HGF has the potential to deliver water soluble complex of curcumin/HP-γ-CyD at the wound site and thereby promote wound healing. These findings may be useful information for preparation of wound dressing materials using sacran, CyDs and drugs.

Curcumin and its topical formulations for wound healing applications

Oxidative damage and inflammation have been identified, through clinical and preclinical studies, as the main causes of nonhealing chronic wounds. Reduction of persistent chronic inflammation by application of antioxidant and anti-inflammatory agents such as curcumin has been well studied. However, low aqueous solubility, poor tissue absorption, rapid metabolism and short plasma half-life have made curcumin unsuitable for systemic administration for better wound healing. Recently, various topical formulations of curcumin such as films, fibers, emulsion, hydrogels and different nanoformulations have been developed for targeted delivery of curcumin at wounded sites. In this review, we summarize and discuss different topical formulations of curcumin with emphasis on their wound-healing properties in animal models.