Formulation and characterisation of alginate hydrocolloid film dressing loaded with gallic acid for potential chronic wound healing

An Investigation into the Structure of Wound-Healing Materials, Chemical Materials, Nature-Based Materials, and Wound Monitoring

With the recent development of advanced industries, in addition to simple abrasions, the demand for wound dressing is gradually increasing in fields such as diabetes care. Factors affecting wound healing include pH, temperature, genetic factors, stress, smoking, and obesity, and studies on these are also increasing. In addition, studies on hydrogels, electrospun nanofibers, foams, films, plant-based materials, chitosan, gelatin, 3D printing, and chemosensors for wound healing are also increasing. However, although there are many data related to wound healing, there are not many studies that have systematically divided them into structures, materials, and monitoring through a review of the literature. Therefore, based on various studies on wound healing, wound-healing materials were classified into structures (films, foams, gauzes, and electrospun nanofibers), chemical materials, nature-based materials, and monitoring sensors, and a literature review was conducted.

Design and characterization of a ROS-responsive antibacterial composite hydrogel for advanced full-thickness wound healing

Full-thickness skin wounds remian a significant and pressing challenge. In this study, we introduce a novel composite hydrogel, CS + GA + Zn-HA. This hydrogel is formulated by incorporating 1 % (1 g/100 mL) of bioactive Zinc-substituted hydroxyapatite nanoparticles (Zn-HA) and 0.2 % (0.2 g/100 mL) of Gallic acid (GA) into chitosan (CS) hydrogels. A 56 % β-glycerophosphate sodium (β-GP) solution serves as the cross-linking agent, and the hydrogel is formed at 37 °C. This composite hydrogel can effectively modulate the wound microenvironment, facilitating comprehensive skin wound healing within two weeks. Physicochemical characterization demonstrates that this hydrogel is thermosensitive, with remarkable swelling behavior, mechanical strength, and drug-delivery performance. In vitro, the GA-incorporated hydrogels possess outstanding reactive oxygen species (ROS) scavenging and antioxidant properties, protecting L929 cells from hydrogen peroxide-induced oxidative damage. The combination of Zn-HA nanoparticles and GA not only augments the functionality of the hydrogel and decreases its degradation rate but also enables the controlled release of curcumin. Moreover, it provides a suitable immune microenvironment in terms of biological effects and significantly boosts the hydrogel's antibacterial ability, as demonstrated by an 89.2 % reduction in E. coli and a 53.6 % reduction in S. aureus. Benefiting from these properties, the CS + GA + Zn-HA composite hydrogel significantly promotes granulation tissue formation, re-epithelialization, angiogenesis, and wound closure in vivo. In conclusion, our research highlights the potential of the CS + GA + Zn-HA hydrogel as a multifunctional scaffold in tissue engineering, providing valuable insights for the design of future wound dressings for diverse wound types.

Assessment of in vitro skin permeation and accumulation of phenolic acids from honey and honey-based pharmaceutical formulations

BACKGROUND

Honey has been successfully used in wound care and cosmetics because of its effective biological properties, including antibacterial, antioxidant, and anti-inflammatory activities. Polyphenols, particularly phenolic acids, are key honey components responsible for these beneficial effects. In recent years, there has been a growing demand for natural, ecologically friendly, and biodegradable products in the modern cosmetics and wound care market. This study aimed to identify and quantify phenolic acids in four Polish honey samples of different botanical origins (heather, buckwheat, linden and rapeseed) and to assess for the first time the permeation of the identified phenolic acids through the skin and their accumulation after the application of pure honey samples, as well as honey-based hydrogel and emulsion formulations.

METHODS

The honey samples' antioxidant activity and total phenolic content were determined using the DPPH and ABTS assays and the Folin-Ciocalteu method, respectively. Phenolic acids and volatile compounds were identified and quantified in honey samples using the HPLC-UV and GC-MS method, respectively. The biocompatibility of the honey samples was evaluated using a murine fibroblast cell line (L929). A Franz-type vertical diffusion cell with porcine skin was used to assess phenolic acid's permeation and skin accumulation from different honey-based pharmaceutical formulations. The biodegradability of the prepared formulations was also characterised.

RESULTS

Gallic acid, 3,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, coumaric acid, and 3-hydroxybenzoic acid were identified and quantified in the honey samples. Heather honey exhibited significantly higher antioxidant activity and total polyphenol content than the other honey samples. Heather, linden and buckwheat honey samples significantly decreased cell viability at concentrations of 5% and 2.5%, while rapeseed honey sample markedly reduced fibroblast viability only at 5%. Among the tested formulations - pure honey, hydrogel, and emulsion - higher skin permeation and accumulation rates of phenolic acids were observed with the prepared honey-based hydrogels than with the pure honeys and emulsions. Additionally, the prepared formulations were classified as partially biodegradable.

CONCLUSIONS

The obtained results confirmed the effectiveness of two pharmaceutical formulations in the form of a hydrogel or emulsion containing honey after applied topically. The inclusion of honey in the vehicle, in particular hydrogel increased the penetration of phenolic acids through the skin.

Lilium candidum Extract Loaded in Alginate Hydrogel Beads for Chronic Wound Healing

Chronic wounds are a major health problem, affecting millions of people worldwide. Resistance to treatment is frequently observed, requiring an extension of the wound healing time, and improper care can lead to more problems in patients. Smart wound dressings that provide a controlled drug release can significantly improve the healing process. In this paper, alginate beads with white lily leaf extract were prepared and tested for chronic wound healing. The obtained beads were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Also, the efficiency of extract encapsulation in alginate was determined as being of. The obtained hydrogel was tested on two normal human cell lines, respectively, dermal fibroblasts (BJ-CRL-2522-ATCC) and endothelial cells (human umbilical vein endothelial cells-HUVEC 2). The longer release of bioactive compounds from plant extract loaded in the alginate hydrogel resulted in more effective wound closure, compared to the extract alone, and scar formation, compared to the alginate hydrogel. Therefore, the effect of the white lily extract in combination with that of sodium alginate hydrogel improves the biological activity of the alginate hydrogel and increases the wound healing properties of the alginate.

Greener healing: sustainable nanotechnology for advanced wound care

Wound healing involves a carefully regulated sequence of events, encompassing pro-inflammatory and anti-inflammatory stages, tissue regeneration, and remodeling. However, in individuals with diabetes, this process gets disrupted due to dysregulation caused by elevated glucose levels and pro-inflammatory cytokines in the bloodstream. Consequently, the pro-inflammatory stage is prolonged, while the anti-inflammatory phase is delayed, leading to impaired tissue regeneration and remodeling with extended healing time. Furthermore, the increased glucose levels in open wounds create an environment conducive to microbial growth and tissue sepsis, which can escalate to the point of limb amputation. Managing diabetic wounds requires meticulous care and monitoring due to the lack of widely available preventative and therapeutic measures. Existing clinical interventions have limitations, such as slow recovery rates, high costs, and inefficient drug delivery methods. Therefore, exploring alternative avenues to develop effective wound-healing treatments is essential. Nature offers a vast array of resources in the form of secondary metabolites, notably polyphenols, known for their antimicrobial, anti-inflammatory, antioxidant, glucose-regulating, and cell growth-promoting properties. Additionally, nanoparticles synthesized through environmentally friendly methods hold promise for wound healing applications in diabetic and non-diabetic conditions. This review provides a comprehensive discussion and summary of the potential wound-healing abilities of specific natural polyphenols and their nanoparticles. It explores the mechanisms of action underlying their efficacy and presents effective formulations for promoting wound-healing activity.

Exploring the underlying pharmacological, immunomodulatory, and anti-inflammatory mechanisms of phytochemicals against wounds: a molecular insight

BACKGROUND

Numerous cellular, humoral, and molecular processes are involved in the intricate process of wound healing.

PHARMACOLOGICAL RELEVANCE

Numerous bioactive substances, such as ß-sitosterol, tannic acid, gallic acid, protocatechuic acid, quercetin, ellagic acid, and pyrogallol, along with their pharmacokinetics and bioavailability, have been reviewed. These phytochemicals work together to promote angiogenesis, granulation, collagen synthesis, oxidative balance, extracellular matrix (ECM) formation, cell migration, proliferation, differentiation, and re-epithelialization during wound healing.

FINDINGS AND NOVELTY

To improve wound contraction, this review delves into how the application of each bioactive molecule mediates with the inflammatory, proliferative, and remodeling phases of wound healing to speed up the process. This review also reveals the underlying mechanisms of the phytochemicals against different stages of wound healing along with the differentiation of the in vitro evidence from the in vivo evidence There is growing interest in phytochemicals, or plant-derived compounds, due their potential health benefits. This calls for more scientific analysis and mechanistic research. The various pathways that these phytochemicals control/modulate to improve skin regeneration and wound healing are also briefly reviewed. The current review also elaborates the immunomodulatory modes of action of different phytochemicals during wound repair.

Exploring the association between a standardized extract of pequi peels (Caryocar brasiliense Cambess) and blue light as a photodynamic therapy for treating superficial wounds

Natural products derived from plants can be used as photosensitizers for antimicrobial photodynamic therapy (aPDT) combining key therapeutic strategies for tissue repair while controlling microorganisms' growth. We investigated a standardized extract of pequi peels (Caryocar brasiliense Cambess) as a brownish natural photosensitizer for aPDT using blue light. Three concentrations of the pequi extract (PE; 10, 30, or 90 μg/mL) were tested solely or associated with blue laser (445 nm, 100 mW, 138 J/cm2, 6 J, 60 s). In vitro, we quantified reactive oxygen species (ROS), assessed skin keratinocytes (HaCat) viability and migration, and aPDT antimicrobial activity on Streptococcus or Staphylococcus strains. In vivo, we assessed wound closure for the most active concentration disclosed by the in vitro assay (30 μg/mL). Upon aPDT treatments, ROS were significantly increased in cell monolayers regardless of PE concentration. PE at low doses stimulates epithelial cells. Although PE stimulated cellular migration, aPDT was moderately cytotoxic to skin keratinocytes, particularly at the highest concentration. The antimicrobial activity was observed for PE at the lowest concentration (10 μg/mL) and mostly at PE 10 μg/mL and 30 μg/mL when used as aPDT photosensitizers. aPDT with PE 30 μg/mL presents antimicrobial activity without compromising the initial phases of skin repair.

Gallic Acid-Loaded Sodium Alginate-Based (Polyvinyl Alcohol-Co-Acrylic Acid) Hydrogel Membranes for Cutaneous Wound Healing: Synthesis and Characterization

Traditional wound dressings often cannot treat wounds caused by bacterial infections or other wound types that are insensitive to these wound treatments. Therefore, a biodegradable, bioactive hydrogel wound dressing could be an effective alternative option. The purpose of this study was to develop a hydrogel membrane comprised of sodium alginate, polyvinyl alcohol, acrylic acid, and gallic acid for treating skin wounds. The newly developed membranes were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), sol-gel fraction, porosity, mechanical strength, swelling, drug release and data modelling, polymeric network parameters, biodegradation, and antioxidation (DPPH and ABTS) and antimicrobial activity against Gram-positive and negative bacteria. The results revealed that hydrogel membranes were crosslinked successfully and had excellent thermal stability, high drug loading, greater mechanical strength, and exhibited excellent biodegradation. Additionally, the swelling ability and the porosity of the surface facilitated a controlled release of the encapsulated drug (gallic acid), with 70.34% release observed at pH 1.2, 70.10% at pH 5.5 (normal skin pH), and 86.24% at pH 7.4 (wounds pH) in 48 h. The gallic acid-loaded hydrogel membranes showed a greater area of inhibition against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria as well as demonstrated excellent antioxidant properties. Based on Franz cell analyses, the permeation flux of the drug from optimized formulations through mice skin was 92 (pH 5.5) and 110 (pH 7.4) μg/cm²·h^-1. Moreover, hydrogel membranes retained significant amounts of drug in the skin for 24 h, such as 2371 (pH 5.5) and 3300 µg/cm² (pH 7.4). Acute dermal irritation tests in rats showed that hydrogel membranes were nonirritating. Hydrogel membranes containing gallic acid could be an effective option for improving wound healing and could result in faster wound healing.

Swelling of Multilayered Calcium Alginate Microspheres for Drug-Loaded Dressing Induced Rapid Lidocaine Release for Better Pain Control

The development of effective drug-loaded dressings has been considered a hot research topic for biomedical therapeutics, including the use of botanical compounds. For wound healing, adequate dressings can provide a good microenvironment for drug release, such as lidocaine. Biological macromolecular materials such as alginate show excellent properties in wound management. This study involves the preparation and evaluation of biocompatible multilayered-structure microspheres composed of chitosan, porous gelatin, and calcium alginate microspheres. The multilayered structure microspheres were named chitosan@ porous gelatin@ calcium alginate microspheres (CPAMs) and the drugs were rapidly released by the volume expansion of the calcium alginate microspheres. The in vitro release curve revealed that the peak release of lidocaine from CPAMs was reached within 18[Formula: see text]min. After 21[Formula: see text]min, the remaining lidocaine was then slowly released, and the active drug release was converted to a passive drug release phase. The initial release effect of lidocaine was much better than that reported in the published studies. Additionally, blood coagulation experiments showed that CPAMs coagulated blood in 60[Formula: see text]s, and the blood liquidity of the CPAMs group was worse than that of the woundplast group. Therefore, the coagulation characteristics of CPAMs were superior to the commonly used woundplast containing lidocaine healing gel. These study outcomes indicated that the CPAMs acted as fast-release dressings for faster pain control and better coagulation properties.

Current Trends in Advanced Alginate-Based Wound Dressings for Chronic Wounds

Chronic wounds represent a major public health issue, with an extremely high cost worldwide. In healthy individuals, the wound healing process takes place in different stages: inflammation, cell proliferation (fibroblasts and keratinocytes of the dermis), and finally remodeling of the extracellular matrix (equilibrium between metalloproteinases and their inhibitors). In chronic wounds, the chronic inflammation favors exudate persistence and bacterial film has a special importance in the dynamics of chronic inflammation in wounds that do not heal. Recent advances in biopolymer-based materials for wound healing highlight the performance of specific alginate forms. An ideal wound dressing should be adherent to the wound surface and not to the wound bed, it should also be non-antigenic, biocompatible, semi-permeable, biodegradable, elastic but resistant, and cost-effective. It has to give protection against bacterial, infectious, mechanical, and thermal agents, to modulate the level of wound moisture, and to entrap and deliver drugs or other molecules This paper explores the roles of alginates in advanced wound-dressing forms with a particular emphasis on hydrogels, nanofibers networks, 3D-scaffolds or sponges entrapping fibroblasts, keratinocytes, or drugs to be released on the wound-bed. The latest research reports are presented and supported with in vitro and in vivo studies from the current literature.