Polymeric films containing pomegranate peel extract based on PVA/starch/PAA blends for use as wound dressing: In vitro analysis and physicochemical evaluation

The Influence of Basil and Cinnamon Essential Oils on Bioactive Sponge Composites of Collagen Reinforced with Hydroxyapatite

The increasing prevalence of acute traumas, surgical wounds, and chronic skin wounds poses significant therapeutic challenges for wound treatment. One of the main concerns in wound care is the danger of infection, which is a significant barrier to healing and a cause of higher morbidity and mortality rates. The emergence of drug-resistant bacterial species is becoming more frequent every day. Antimicrobial dressings have become a viable strategy for wound healing and hospital expense savings. Several factors, such as the wound's localization and state, microbial load, and cost, must be considered when choosing an appropriate antimicrobial dressing. One of the key goals of wound care is infection avoidance. This study addresses the therapeutic challenges of acute traumas, surgical wounds, and chronic skin wounds, focusing on infection prevention and combating drug-resistant bacterial strains. The research explores the development of novel composite wound dressings incorporating hydroxyapatite, known for its osteoconductive properties, and essential oils from basil and cinnamon, recognized for their antimicrobial activity. The study evaluates the impact of these additives on key properties such as surface morphology, water absorption, enzymatic degradation, and mechanical performance. Antimicrobial tests showed that two experimental samples (A1S and A1BS) exhibited significant activity against Escherichia coli but not on Staphylococcus aureus. The results highlight the dressings' enhanced antimicrobial properties, mechanical strength, and controlled degradation, making them promising candidates for advanced wound healing. Tailored applications were identified, with each dressing composition offering unique benefits for specific wound-healing scenarios based on the balance between flexibility, structural support, and bioactivity.

The Promoting Effect of Animal Bioactive Proteins and Peptide Components on Wound Healing: A Review

The skin is the first line of defense to protect the host from external environmental damage. When the skin is damaged, the wound provides convenience for the invasion of external substances. The prolonged nonhealing of wounds can also lead to numerous subsequent complications, seriously affecting the quality of life of patients. To solve this problem, proteins and peptide components that promote wound healing have been discovered in animals, which can act on key pathways involved in wound healing, such as the PI3K/AKT, TGF-β, NF-κ B, and JAK/STAT pathways. So far, some formulations for topical drug delivery have been developed, including hydrogels, microneedles, and electrospinning nanofibers. In addition, some high-performance dressings have been utilized, which also have great potential in wound healing. Here, research progress on the promotion of wound healing by animal-derived proteins and peptide components is summarized, and future research directions are discussed.

Antibacterial gelatin/tragacanth gum films containing galbanum essential oil for in vitro scratch-healing

Natural substances and bioactive agents possess great potential in wound care based on their ability to promote healing and prevent infection. This study focused on the fabrication of antibacterial wound dressings by combining gelatin (G), tragacanth gum (TG), and galbanum essential oil (GEO) as a loaded drug. TG addition resulted in more elastic and flexible films besides enabling encapsulation of the hydrophobic GEO into the biopolymeric matrix. GEO was utilized as an antibacterial and a wound-healing enhancer for open wounds such as incisions. Field emission scanning electron microscopy (FE-SEM) analysis revealed a porous film structure after GEO incorporation. Higher GEO concentration caused reduced swelling and slower degradation. Water vapor transfer rate varied from 596 to 894 g/m2.day, making the films suitable for wound dressings. GEO release exhibited a two-phase profile with prolonged diffusion-controlled release for a higher content of GEO. The films demonstrated dose-dependent antimicrobial activity against S. aureus and E. coli strains. Effectiveness and noteworthy application of this research were approved by scratch assay on human dermal fibroblast cells, and films with 3 % GEO showed 79.42 % wound closure, which is significantly higher than the control sample (55.15 %), indicating promoted cell migration and promising wound healing properties.

Sustainable Collagen Film Preparation with Tannins Extracted from Moroccan Pomegranate Byproduct Varieties: Thermal, Structural, and Nanoscaled Studies

Recently, obtaining collagen films using a cross-linking technique has been a successful strategy. The current investigation used six cross-linker extracts (CE) from six different pomegranate varieties' byproducts to make and characterize collagen-tannin films using acid-soluble collagen (SC). The polymeric film has a yellow hue after CE incorporation. Fourier transform infrared spectroscopy assessed the impact of CE and its successful interaction within the matrix. The shifts verify different interactions between extracts and collagen functional groups, where they likely form new hydrogen bonds, retaining their helix structure without damaging the matrix. Scanning electron microscopy was used to analyze the morphology and fiber size. The average diameter of the fibers was found to be about 3.64 μm. Thermal behaviors (denaturation and degradation) were investigated by thermogravimetric analysis. The weight losses of cross-linked films increased by around 20% compared to non-cross-linked ones. This phenomenon was explained by the absence of telopeptide sections in the collagen helical structure, typically reinforced by lysine and hydroxylysine covalent linkages. Nanoscaled observations were also accomplished using transmission electron microscopy (TEM) on SC and SC-CE. The TEM analysis confirmed the CE polymerization degree effect on the cross-linking density via the overlap sequences, ranging up to 32.38 ± 2.37 nm on the fibril. The prepared biodegradable collagen-tannin film showed higher cross-linking density, which is expected to improve the biomaterial applications of collagen films while exploiting the underrated pomegranate byproducts.

Biophysical studies of modified PVC sheet based on sunflower oil for antistatic and blood bags applications

In this work, the surface of polyvinyl chloride PVC sheet was modified by blending it with sunflower seed oil SSO to obtain PVC sheet/SSO films of ratios 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (v/v)% using the solution casting method. Various techniques were used to characterize the prepared films, besides the use of hemolysis assays and blood clot formation tests. FTIR spectra revealed that there was a good interaction between the PVC sheet and the oil. The dielectric measurement indicated that SSO addition enhanced the dielectric properties of the sheet. The study of dielectric relaxation times confirmed the interaction between SSO and the sheet. DC conductivity increased to 6 × 10-6 S/m, so it could be applied in antistatic applications. Also, SSO addition increased the value of the thermal stability. According to SEM micrographs, the film was roughened at a ratio of 60/40 and smoothed out at 50/50. This behavior was confirmed with roughness and contact angle measurement results, in which the film of ratio 60/40 had the highest value equal to (72.03°) and then decreased at 50/50 to (59.62°). These results were confirmed by XRD measurement as the crystallinity increased at the film ratio of 60/40 and decreased again at 50/50. Also, the ratio of 60/40 demonstrated a large decrease in thrombus weights along with a slight increase in hemolysis, which is within the acceptable range and has a high degree of biocompatibility, so this concentration is recommended to be used in blood bags applications.

Design, optimization and pharmaceutical characterization of wound healing film dressings with chloramphenicol and ibuprofen

OBJECTIVE

The aim of the present study was to develop and optimize a wound dressing film loaded with chloramphenicol (CAM) and ibuprofen (IBU) using a Quality by Design (QbD) approach.

SIGNIFICANCE

The two drugs have been combined in the same dressing as they address two critical aspects of the wound healing process, namely prevention of bacterial infection and reduction of inflammation and pain related to injury.

METHODS

Three critical formulation variables were identified, namely the ratios of Kollicoat SR 30D, polyethylene glycol 400 and polyvinyl alcohol. These variables were further considered as factors of an experimental design, and 17 formulations loaded with CAM and IBU were prepared via solvent casting. The films were characterized in terms of dimensions, mechanical properties and bioadhesion. Additionally, the optimal formulation was characterized regarding tensile properties, swelling behavior, water vapor transmission rate, surface morphology, thermal behavior, goniometry, in vitro drug release, cell viability, and antibacterial activity.

RESULTS

The film was optimized by setting minimal values for the folding endurance, adhesive force and hardness. The optimally formulated film showed good fluid handling properties in terms of swelling behavior and water vapor transmission rate. IBU and CAM were released from the film up to 80.9% and 82.5% for 8 h. The film was nontoxic, and the antibacterial activity was prominent against Micrococcus spp. and Streptococcus pyogenes.

CONCLUSIONS

The QbD approach was successfully implemented to develop and optimize a novel film dressing promising for the treatment of low-exuding acute wounds prone to infection and inflammation.

A review of the current state of natural biomaterials in wound healing applications

Skin, the largest biological organ, consists of three main parts: the epidermis, dermis, and subcutaneous tissue. Wounds are abnormal wounds in various forms, such as lacerations, burns, chronic wounds, diabetic wounds, acute wounds, and fractures. The wound healing process is dynamic, complex, and lengthy in four stages involving cells, macrophages, and growth factors. Wound dressing refers to a substance that covers the surface of a wound to prevent infection and secondary damage. Biomaterials applied in wound management have advanced significantly. Natural biomaterials are increasingly used due to their advantages including biomimicry of ECM, convenient accessibility, and involvement in native wound healing. However, there are still limitations such as low mechanical properties and expensive extraction methods. Therefore, their combination with synthetic biomaterials and/or adding bioactive agents has become an option for researchers in this field. In the present study, the stages of natural wound healing and the effect of biomaterials on its direction, type, and level will be investigated. Then, different types of polysaccharides and proteins were selected as desirable natural biomaterials, polymers as synthetic biomaterials with variable and suitable properties, and bioactive agents as effective additives. In the following, the structure of selected biomaterials, their extraction and production methods, their participation in wound healing, and quality control techniques of biomaterials-based wound dressings will be discussed.

An Electroconductive and Antibacterial Adhesive Nanocomposite Hydrogel for High-Performance Skin Wound Healing

Multifunctional hydrogel adhesives inhibiting infections and enabling the electrical stimulation (ES) of tissue reparation are highly desirable for the healing of surgical wounds and other skin injuries. Herein, a therapeutic nanocomposite hydrogel is designed by integrating β-cyclodextrin-embedded Ag nanoparticles (CDAgNPs) in a polyvinyl alcohol (PVA) matrix enhanced with free β-cyclodextrin (CD) and an atypical macromolecule made of β-glucan grafted with hyaluronic acid (HAG). The main objective is to develop a biocompatible dressing combining the electroconductivity and antibacterial activity of CDAgNPs with the cohesiveness and porosity of PVA and the anti-inflammatory, moisturizing, and cell proliferation-promoting properties of HAG. The last component, CD, is added to strengthen the network structure of the hydrogel. PVA/CD/HAG/CDAgNP exhibited excellent adhesion strength, biocompatibility, electroconductivity, and antimicrobial activity against a wide range of bacteria. In addition, the nanocomposite hydrogel has a swelling ratio and water retention capacity suitable to serve as a wound dressing. PVA/CD/HAG/CDAgNP promoted the proliferation of fibroblast in vitro, accelerated the healing of skin wounds in an animal model, and is hemostatic. Upon ES, the PVA/CD/HAG/CDAgNP nanocomposite hydrogel became more efficient both in vitro and in vivo further speeding up the skin healing process thus demonstrating its potential as a next-generation electroconductive wound dressing.

Multifunctional Pomegranate Peel Microparticles with Health-Promoting Effects for the Sustainable Development of Novel Nutraceuticals and Pharmaceuticals

Recovering the bioactive components from pomegranate peel (PP) in the fruit-processing industry has attracted great attention in terms of minimizing the waste burden, as well as providing a new source of a multitude of functional compounds. The present study aimed to develop a feasible microencapsulation process of PP extract by using pectin and a pectin/2-hydroxypropyl-β-cyclodextrin (HP-β-CD) blend as coating materials. Microsized powders obtained by a spray drying technique were examined in terms of technological characteristics, exhibiting high powder yield and desirable moisture content, flowability, and cohesive properties. Assuming that the interactions with the used biopolymers occur on the surface hydrophobic domain, their presence significantly improved the thermal stability of the microencapsulated powders up to 200 °C. The health-promoting effects of PP have been associated with its high content in ellagitannins, particularly punicalagin. The obtained PP powders exhibited strong antioxidant and hypoglycemic potential, while an antimicrobial assay revealed their potent activity against Gram-positive bacteria. Additionally, an in vitro release study suggested that the used biopolymers can modify the release of target bioactive compounds, thus establishing a basis for developing an oral-controlled release system. Altogether, biowaste valorization from PP by the production of effective multifunctional microsized powders represents a sustainable way to obtain novel nutraceuticals and/or pharmaceuticals.

Polysaccharide-Based Coatings as Drug Delivery Systems

Therapeutic polysaccharide-based coatings have recently emerged as versatile strategies to transform a conventional medical implant into a drug delivery system. However, the translation of these polysaccharide-based coatings into the clinic as drug delivery systems still requires a deeper understanding of their drug degradation/release profiles. This claim is supported by little or no data. In this review paper, a comprehensive description of the benefits and challenges generated by the polysaccharide-based coatings is provided. Moreover, the latest advances made towards the application of the most important representative coatings based on polysaccharide types for drug delivery are debated. Furthermore, suggestions/recommendations for future research to speed up the transition of polysaccharide-based drug delivery systems from the laboratory testing to clinical applications are given.

Bioprospecting a Film-Forming System Loaded with Eugenia uniflora L. and Tropaeolum majus L. Leaf Extracts for Topical Application in Treating Skin Lesions

Natural products can be used as complements or as alternatives to synthetic drugs. Eugenia uniflora and Tropaeolum majus are natives of Brazil and have antimicrobial, anti-inflammatory, and antioxidant activities. This study aimed to develop a film-forming system (FFS) loaded with plant extracts with the potential for treating microbial infections. E. uniflora and T. majus leaf extracts were prepared and characterized, and the individual and combined antioxidant and antimicrobial activities were evaluated. The FFS was developed with different concentrations of polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and analyzed for physicochemical characteristics. The combination of extracts showed a superior antioxidant effect compared to the individual extracts, justifying the use of the blend. FFS prepared with 4.5% PVA, 4.5% PVP, 7.81% E. uniflora extract, and 3.90% T. majus extract was adhesive, lacked scale formation, presented good malleability, and had a suitable pH for topical application. In addition, the viscosity at rest was satisfactory for maintaining stability; water solubility was adequate; skin permeation was low; and the antimicrobial effect was superior to that of the individual extracts. Therefore, the developed FFS is promising for the differentiated treatment of skin lesions through topical application.

Films for Wound Healing Fabricated Using a Solvent Casting Technique

Wound healing is a complex process that involves restoring the structure of damaged tissues through four phases: hemostasis, inflammation, proliferation, and remodeling. Wound dressings are the most common treatment used to cover wounds, reduce infection risk and the loss of physiological fluids, and enhance wound healing. Despite there being several types of wound dressings based on different materials and fabricated through various techniques, polymeric films have been widely employed due to their biocompatibility and low immunogenicity. Furthermore, they are non-invasive, easy to apply, allow gas exchange, and can be transparent. Among different methods for designing polymeric films, solvent casting represents a reliable, preferable, and highly used technique due to its easygoing and relatively low-cost procedure compared to sophisticated methods such as spin coating, microfluidic spinning, or 3D printing. Therefore, this review focuses on the polymeric dressings obtained using this technique, emphasizing the critical manufacturing factors related to pharmaceuticals, specifically discussing the formulation variables necessary to create wound dressings that demonstrate effective performance.

Fortification of chocolates with high-value-added plant-based substances: Recent trends, current challenges, and future prospects

High consumption of delicious foods, such as chocolates, is considered excellent snacks, capable of converting from health-threatening to great functional foods. The fortification of chocolates with high-value-added plant-based substances might improve their healthful effects, nutritional properties, and shelf life. Chocolate could be an effective carrier for plant-based substances delivery, and it could be an effective vehicle to treat and reduce the indications of disease, such as obesity, overweight, hypertension, stress, cardiovascular failure, congestive heart failure, and diabetes. Referring to the recent studies in chocolate fortification with high-value-added plant-based substances, it seems that the recent trends are toward its therapeutic effects against noncommunicable diseases. Despite the undeniable functional effects of fortified chocolates, there are some challenges in the fortification way of chocolates. In other words, their functional characteristics, such as rheological and sensory attributes, may undesirably change. It seems that encapsulation techniques, such as spray drying, antisolvent precipitation, nanoemulsification, and liposomal encapsulation, could almost overcome these challenges. Thus, several studies focused on designing and fabricating nanoscale delivery systems with the aim of chocolate fortification, which is discussed.

Agaricus blazei Murill extract-loaded in alginate/poly(vinyl alcohol) films prepared by Ca2+ cross-linking for wound healing applications

This work aimed the development and evaluation of the wound healing activity of films based on sodium alginate, polyvinyl alcohol (PVA) and Ca²⁺ loaded with Agaricus blazei Murill hydroalcoholic extract (AbE). Firstly, AbE was prepared using a previously standardized methodology. The films were prepared by casting technique and cross-linked with Ca²⁺ using CaCl₂ as cross-linking agent. The physicochemical, morphological and water vapor barrier properties of the films were analyzed and the pre-clinical efficacy was investigated against the cutaneous wound model in mice. The films showed barrier properties to water vapor promising for wound healing. AbE showed physical and chemical interactions between both polymers, noticed by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermal analysis. The delivery of AbE in alginate/PVA films enhanced the antioxidant and wound healing properties of these polymers. Consequently, a reduction of malondialdehyde levels was observed, as well as an increase of the epidermis/dermis thickness and enhancement in collagen I deposition. Thus, these formulations are promising biomaterials for wound care and tissue repairing.

Bioengineered Water-Responsive Carboxymethyl Cellulose/Poly(vinyl alcohol) Hydrogel Hybrids for Wound Dressing and Skin Tissue Engineering Applications

The burden of chronic wounds is growing due to the increasing incidence of trauma, aging, and diabetes, resulting in therapeutic problems and increased medical costs. Thus, this study reports the synthesis and comprehensive characterization of water-responsive hybrid hydrogels based on carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) using citric acid (CA) as the chemical crosslinking agent, with tunable physicochemical properties suitable to be applied as a wound dressing for soft tissue engineering applications. They were produced through an eco-friendly process under mild conditions. The hydrogels were designed and produced with flexible swelling degree properties through the selection of CMC molecular mass (Mw = 250 and 700 kDa) and degree of functionalization (DS = 0.81), degree of hydrolysis of PVA (DH > 99%, Mw = 84-150 kDa) associated with synthesis parameters, CMC/PVA ratio and extension of chemical crosslinking (CA/CMC:PVA ratio), for building engineered hybrid networks. The results demonstrated that highly absorbent hydrogels were produced with swelling degrees ranging from 100% to 5000%, and gel fraction from 40% to 80%, which significantly depended on the concentration of CA crosslinker and the presence of PVA as the CMC-based network modifier. The characterizations indicated that the crosslinking mechanism was mostly associated with the chemical reaction of CA carboxylic groups with hydroxyl groups of CMC and PVA polymers forming ester bonds, rendering a hybrid polymeric network. These hybrid hydrogels also presented hydrophilicity, permeability, and structural features dependent on the degree of crosslinking and composition. The hydrogels were cytocompatible with in vitro cell viability responses of over 90% towards model cell lines. Hence, it is envisioned that this research provides a simple strategy for producing biocompatible hydrogels with tailored properties as wound dressings for assisting chronic wound healing and skin tissue engineering applications.

Optimizing Biodegradable Starch-Based Composite Films Formulation for Wound-Dressing Applications

This paper utilizes response surface methodology (RSM) design-based analyses to optimize starch-based wound dressings that were characterized based on weight loss (WL%), swelling index (SI%), and mechanical strength (TS). The wound-dressing materials were prepared by employing a modified casting method, using various concentrations of starch (0.5-2 w/w%), polyvinyl alcohol (PVA) (0.5-2 weight%), citric acid (1.5-4 weight%), and glycerol (1.5-4 weight%) to yield wound-dressing films with appropriate combinations of in vitro degradation, swelling index, and tensile strength. As a result of the response surface method-based analysis, the swelling index, in vitro degradation, and tensile strength were linearly related to variations in the formulation of organic components. Based on our experimental investigations, the optimized film (formulation: 1 weight% PVA, 2 weight% starch, 1.5 weight% citric acid, and 1.5 weight% glycerol) exhibited an outstanding swelling index (343.52%), suitable in vitro degradation (53.22%), and excellent tensile strength (8.82 MPa). The response surface plots for the dependent variables, swelling index (SI%), weight loss (WL%), and mechanical strength (TS), showed that in all dual relations, the PVA-starch combination significantly affected all dependent variables; however, the PVA-citric acid interaction showed the most excellent effect on the swelling index. As a result, every component of the resulting film had a lesser amount of all ingredients to achieve better properties at a lower material cost. Starch-based/PVA films have been identified in this paper as optimal and more affordable wound-dressing films.

Preparation and Characterization of Eco-Friendly Transparent Antibacterial Starch/Polyvinyl Alcohol Materials for Use as Wound-Dressing

In this study, eco-friendly and transparent starch-based/polyvinyl alcohol/citric acid composite films are evaluated for their efficacy as wound dressing materials. The starch/polyvinyl alcohol (PVA) materials with added citric acid (0.46-1.83 wt%) and glycerol were made and handled based on the modified casting method. This new formulation decreases the amount of PVA used in the conventional preparation method. Citric acid ensures an appropriate antibacterial environment for wound-dressing materials. The mechanical, chemical, and surface morphological properties of such films were assessed and analyzed by tensile strength tests, UV-Vis spectrometry, swelling index, and scanning electron microscopy (SEM). Furthermore, the water vapor transmission (WVT) quantity was measured for an ideal wound-healing process to investigate an optimal moisture environment around the wound bed. Moreover, the pH level of the dressings was measured to examine the possibility of bacterial growth around these starch-based films. Additionally, the films' in-vitro antibacterial activities were studied against the two most common Gram-positive and Gram-negative bacteria (Escherichia coli and Staphylococcus aureus). The new starch-based dressings demonstrated suitable degradation, antibacterial activity, fluid absorption, and adequate mechanical strength, representing wound-dressing materials' vital features.

Starch as a Matrix for Incorporation and Release of Bioactive Compounds: Fundamentals and Applications

Due to its abundance in nature and low cost, starch is one of the most relevant raw materials for replacing synthetic polymers in a number of applications. It is generally regarded as non-toxic, biocompatible, and biodegradable and, therefore, a safe option for biomedical, food, and packaging applications. In this review, we focused on studies that report the use of starch as a matrix for stabilization, incorporation, or release of bioactive compounds, and explore a wide range of applications of starch-based materials. One of the key application areas for bioactive compounds incorporated in starch matrices is the pharmaceutical industry, especially in orally disintegrating films. The packaging industry has also shown great interest in using starch films, especially those with antioxidant activity. Regarding food technology, starch can be used as a stabilizer in nanoemulsions, thus allowing the incorporation of bioactive compounds in a variety of food types. Starch also presents potential in the cosmetic industry as a delivery system. However, there are still several types of industry that could benefit from the incorporation of starch matrices with bioactive compounds, which are described in this review. In addition, the use of microbial bioactive compounds in starch matrices represents an almost unexplored field still to be investigated.

Formulation, Characterization and Optimization of β-Glucan and Pomegranate Juice Based Films for Its Potential in Diabetes

The aim of this study was to develop films based on β-glucans in association with pomegranate juice for its potential in metabolic disorders such as diabetes due to plenty of bioactive compounds from the film composition. Initially, a Box-Behnken design was generated by varying the level of β-glucan content (0.5, 1, 1.5 g), sodium alginate (0.2, 0.4, 0.6 g) and pomegranate juice (10, 20, 30 mL) for development of films. Subsequently, glycerin was added as 25% of the total dry matter. The optimization of the films prepared by the solvent casting method was conducted based on the different responses such as: water vapor transmission rate (WVTR), water vapor permeability (WVP), thickness, density, moisture content, solubility, film opacity and color. The water activity profile and FT-IR analysis were performed in all tests. The model was used to determine the optimal experimental values considering that the optimal film will make a sustained contribution to diabetes. The optimal values of the film sample made of β-glucans, sodium alginate, pomegranate juice and glycerin make it befitting for packaging dry powdered pharmaceuticals. Finally, antimicrobial activity against Gram-negative and Gram-positive bacteria, UV barrier properties and microcrack and pore detections through SEM were also investigated for the optimal film sample.

Preparing and Characterizing Novel Biodegradable Starch/PVA-Based Films with Nano-Sized Zinc-Oxide Particles for Wound-Dressing Applications

Given recent worldwide environmental concerns, biodegradability, antibacterial activity, and healing properties around the wound area are vital features that should be taken into consideration while preparing biomedical materials such as wound dressings. Some of the available wound dressings present some major disadvantages. For example, low water vapor transmission rate (WVTR), inadequate exudates absorption, and the complex and high environmental cost of the disposal/recycling processes represent such drawbacks. In this paper, starch/polyvinyl alcohol (PVA) material with inserted nano-sized zinc-oxide particles (nZnO) (average size ≤ 100 nm) was made and altered using citric acid (CA). Both ensure an efficient antibacterial environment for wound-dressing materials. The film properties were assessed by UV–Vis spectrometry and were validated against the UV light transmission percentage of the starch/ polyvinyl alcohol (PVA)/ zinc-oxide nanoparticles (nZnO) composites. Analyses were conducted using X-ray Spectroscopy (EDX) and scanning electron microscopy (SEM) to investigate the structure and surface morphology of the materials. Moreover, to validate an ideal moisture content around the wound area, which is necessary for an optimum wound-healing process, the water vapor transmission rate of the film was measured. The new starch-based materials exhibited suitable physical and chemical properties, including solubility, gel fraction, fluid absorption, biodegradability, surface morphology (scanning electron microscopy imaging), and mechanical properties. Additionally, the pH level of the starch-based/nZnO film was measured to study the prospect of bacterial growth on this wound-dressing material. Furthermore, the in vitro antibacterial activity demonstrated that the dressings material effectively inhibited the growth and penetration of bacteria (Escherichia coli, Staphylococcus aureus).

Development and Characterization of Gentamicin-Loaded Arabinoxylan-Sodium Alginate Films as Antibacterial Wound Dressing

Biopolymer-based antibacterial films are attractive materials for wound dressing application because they possess chemical, mechanical, exudate absorption, drug delivery, antibacterial, and biocompatible properties required to support wound healing. Herein, we fabricated and characterized films composed of arabinoxylan (AX) and sodium alginate (SA) loaded with gentamicin sulfate (GS) for application as a wound dressing. The FTIR, XRD, and thermal analyses show that AX, SA, and GS interacted through hydrogen bonding and were thermally stable. The AXSA film displays desirable wound dressing characteristics: transparency, uniform thickness, smooth surface morphology, tensile strength similar to human skin, mild water/exudate uptake capacity, water transmission rate suitable for wound dressing, and excellent cytocompatibility. In Franz diffusion release studies, >80% GS was released from AXSA films in two phases in 24 h following the Fickian diffusion mechanism. In disk diffusion assay, the AXSA films demonstrated excellent antibacterial effect against E.coli, S. aureus, and P. aeruginosa. Overall, the findings suggest that GS-loaded AXSA films hold potential for further development as antibacterial wound dressing material.

Composite Membrane Dressings System with Metallic Nanoparticles as an Antibacterial Factor in Wound Healing

Wound management is the burning problem of modern medicine, significantly burdening developed countries’ healthcare systems. In recent years, it has become clear that the achievements of nanotechnology have introduced a new quality in wound healing. The application of nanomaterials in wound dressing significantly improves their properties and promotes the healing of injuries. Therefore, this review paper presents the subjectively selected nanomaterials used in wound dressings, including the metallic nanoparticles (NPs), and refers to the aspects of their application as antimicrobial factors. The literature review was supplemented with the results of our team’s research on the elements of multifunctional new-generation dressings containing nanoparticles. The wound healing multiple molecular pathways, mediating cell types, and affecting agents are discussed herein. Moreover, the categorization of wound dressings is presented. Additionally, some materials and membrane constructs applied in wound dressings are described. Finally, bacterial participation in wound healing and the mechanism of the antibacterial function of nanoparticles are considered. Membranes involving NPs as the bacteriostatic factors for improving wound healing of skin and bones, including our experimental findings, are discussed in the paper. In addition, some studies of our team concerning the selected bacterial strains’ interaction with material involving different metallic NPs, such as AuNPs, AgNPs, Fe₃O₄NPs, and CuNPs, are presented. Furthermore, nanoparticles’ influence on selected eukaryotic cells is mentioned. The ideal, universal wound dressing still has not been obtained; thus, a new generation of products have been developed, represented by the nanocomposite materials with antibacterial, anti-inflammatory properties that can influence the wound-healing process.

Upcycling Biodegradable PVA/Starch Film to a Bacterial Biopigment and Biopolymer

Meeting the challenge of circularity for plastics requires amenability to repurposing post-use, as equivalent or upcycled products. In a compelling advancement, complete circularity for a biodegradable polyvinyl alcohol/thermoplastic starch (PVA/TPS) food packaging film was demonstrated by bioconversion to high-market-value biopigments and polyhydroxybutyrate (PHB) polyesters. The PVA/TPS film mechanical properties (tensile strength (σ_u), 22.2 ± 4.3 MPa; strain at break (ε_u), 325 ± 73%; and Young’s modulus (E), 53–250 MPa) compared closely with low-density polyethylene (LDPE) grades used for food packaging. Strong solubility of the PVA/TPS film in water was a pertinent feature, facilitating suitability as a carbon source for bioprocessing and microbial degradation. Biodegradability of the film with greater than 50% weight loss occurred within 30 days of incubation at 37 °C in a model compost. Up to 22% of the PVA/TPS film substrate conversion to biomass was achieved using three bacterial strains, Ralstonia eutropha H16 (Cupriavidus necator ATCC 17699), Streptomyces sp. JS520, and Bacillus subtilis ATCC6633. For the first time, production of the valuable biopigment (undecylprodigiosin) by Streptomyces sp. JS520 of 5.3 mg/mL and the production of PHB biopolymer at 7.8% of cell dry weight by Ralstonia eutropha H16 from this substrate were reported. This low-energy, low-carbon post-use PVA/TPS film upcycling model approach to plastic circularity demonstrates marked progress in the quest for sustainable and circular plastic solutions.

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

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

Therapeutic candidates for keloid scars identified by qualitative review of scratch assay research for wound healing

The scratch assay is an in vitro technique used to analyze cell migration, proliferation, and cell-to-cell interaction. In the assay, cells are grown to confluence and then ‘scratched’ with a sterile instrument. For the cells in the leading edge, the resulting polarity induces migration and proliferation in attempt to ‘heal’ the modeled wound. Keloid scars are known to have an accelerated wound closure phenotype in the scratch assay, representing an overactivation of wound healing. We performed a qualitative review of the recent literature searching for inhibitors of scratch assay activity that were already available in topical formulations under the hypothesis that such compounds may offer therapeutic potential in keloid treatment. Although several shortcomings in the scratch assay literature were identified, caffeine and allicin successfully inhibited the scratch assay closure and inflammatory abnormalities in the commercially available keloid fibroblast cell line. Caffeine and allicin also impacted ATP production in keloid cells, most notably with inhibition of non-mitochondrial oxygen consumption. The traditional Chinese medicine, shikonin, was also successful in inhibiting scratch closure but displayed less dramatic impacts on metabolism. Together, our results partially summarize the strengths and limitations of current scratch assay literature and suggest clinical assessment of the therapeutic potential for these identified compounds against keloid scars may be warranted.

Anthocyanin Hybrid Nanopigments from Pomegranate Waste: Colour, Thermomechanical Stability and Environmental Impact of Polyester-Based Bionanocomposites

In the present work, anthocyanin (ACN) hybrid nanopigments were synthetized by using a natural pomegranate dye (PD) and calcined hydrotalcite (HT) and montmorillonite (MMT) nanoclays. A wide colour gamut was obtained with MMT-based nanopigments ranging from reddish to bluish hues caused by structural transformations of ACNs at different pH values. However, a buffer effect was observed with HT obtaining samples a similar final colour regardless of the synthesis conditions. Nanopigments added with a biomordant extracted from pomegranate peels showed a different colour compared to the incorporation of a commercial mordant due to the intrinsic colouring properties of the pomegranate bioadditive. The developed nanopigments were incorporated at 7 wt% loading to produce novel polyester-based bionanocomposites which were characterized in terms of thermal, mechanical and colour properties. The encapsulation of PD into the nanoclays improved its thermal stability, in particular for MMT-based nanopigments. The pH changes observed during the nanofillers synthesis affected the final colour of the MMT-based nanocomposites, inducing a general increase in ∆E* and a decrease in gloss values. Slight improvements were obtained in terms of elastic modulus for MMT-based polymer samples confirming the applicability of the developed bionanocomposites as colouring and reinforcement materials. A very similar environmental profile was obtained for MMT and HT-based nanofillers showing MMT-based nanopigments a slightly better general behaviour. The results of the LCA study evidenced the suitability of the processes used in this work to the circular bioeconomy approach through sustainable food waste management and the production of bioplastics using waste substrates.

Characterization of a flavonol-rich antioxidant fraction from Spondias purpurea L. pulp and the effect of its incorporation on cellulose acetate-based film

BACKGROUND

Active packaging containing natural flavonoid has recently emerged as a result of its potential to inhibit the oxidation of foods by interacting with it and/or its surrounding environment, with the aim of counteracting oxidation reactions and extending the shelf-life of foods. The plant Spondias purpurea L. is widely found in northeastern Brazil and is known to contain bioactive flavonoids. The present study aimed to obtain a flavonoid-rich fraction from the pulp of S. purpurea L. and incorporate it into the cellulose acetate film to obtain biodegradable films with antioxidant properties.

RESULTS

The fractionation in SiO₂ open-column chromatography of the S. purpurea pulp crude extract furnished an antioxidant active fraction containing the flavonols quercetin 3-O-rutinoside and kaempferol 3-O-rutinoside as the major compounds. This active fraction was incorporated (10, 20 and 30 g kg^-1 ) into the substance produced with the casting method for cellulose acetate films. The films produced were characterized concerning mechanical properties, water vapor permeability (WVP) and antioxidant activity.

CONCLUSION

The incorporation of the active flavonoid fraction from S. purpurea in the cellulose acetate films decreases WVP and elongation at break, at the same time as increasing antioxidant activity, tensile strength and elastic modulus. Thus, the S. purpurea pulps may be an alternative as a source of antioxidants for use in cellulose acetate films. © 2020 Society of Chemical Industry.

Polymeric-based drug delivery systems for veterinary use: State of the art

One of the challenges to the success of veterinary pharmacotherapy is the limited number of drugs and dosage forms available exclusively to this market, due to the interspecies variability of animals, such as anatomy, physiology, pharmacokinetics, and pharmacodynamics. For this reason, studies in this area have become a highlight, since they are still scarce in comparison with those on human drug use. To overcome many limitations related to the bioavailability, efficacy, and safety of pharmacotherapy in animals, especially livestock and domestic animals, polymers-based drug delivery systems are promising tools if they guarantee greater selectivity and less toxicity in dosage forms. In addition, these tools may be developed according to the great interspecies variability. To contribute to these discussions, this paper provides an updated review of the major polymer-based drug delivery systems projected for veterinary use. Traditional and innovative drug delivery systems based on polymers are presented, with an emphasis on films, microparticles, micelles, nanogels, nanoparticles, tablets, implants and hydrogel-based drug delivery systems. We discuss important concepts for the veterinarian about the mechanisms of drug release and, for the pharmacist, the advantages in the development of pharmaceutical forms for the animal population. Finally, challenges and opportunities are presented in the field of pharmaceutical dosage forms for veterinary use in response to the interests of the pharmaceutical industry.

Two Fascinating Polysaccharides: Chitosan and Starch. Some Prominent Characterizations for Applying as Eco-Friendly Food Packaging and Pollutant Remover in Aqueous Medium. Progress in Recent Years: A Review

The call to use biodegradable, eco-friendly materials is urgent. The use of biopolymers as a replacement for the classic petroleum-based materials is increasing. Chitosan and starch have been widely studied with this purpose: to be part of this replacement. The importance of proper physical characterization of these biopolymers is essential for the intended application. This review focuses on characterizations of chitosan and starch, approximately from 2017 to date, in one of their most-used applications: food packaging for chitosan and as an adsorbent agent of pollutants in aqueous medium for starch.

Design and fabrication of electrospunMorinda citrifolia-based nanofibrous scaffold as skin wound dressing material:in vitroandin silicoanalysis

Wound healing is an urgent problem that impacts quality of life, and the need for biomaterials suitable for the treatment of skin wound healing disease is increasing annually. Innovative biomaterials and treatments for skin abrasions are being relentlessly researched and established in order to improve treatment efficacy. Here, we describe a novel electrospun polymeric nanofibrous scaffold enriched with pharmaceutical bioactive materials extracted fromMorinda citrifolia(MC), which demonstrated efficient skin wound healing therapy due to its excellent human skin keratinocyte proliferation and adhesion inin vitroanalysis. Surface morphological analysis was used to reveal the nano-architectural structure of the electrospun scaffolds. The fabricated nanofibers displayed good antibacterial efficacy by creating an inhibitory zone for the pathogenic microbes studied. MC supported active healing due to the presence of pharmaceuticals associated with wound healing, as revealed by the results of gas chromatography-mass spectrometry and the prediction of activity spectra for substances (PASS) analysis. Since MC is a multi-potential therapeutic herbal plant, it was found that the linoleic acid, olelic acid, and diethyl phthalate present in the extract supported the wound healing proteins glycogen-synthase-kinase-3-β-protein and Protein Data Bank-1Q5K with binding energies of -4.6, -5.2, and -5.9 kcal mol^-1, as established by the results ofin silicoanalysis. Thus, by being hydrophilic in nature, targeting wound proteins, increasing the proliferation and adhesion of keratinocytes and combating pathogens, the nanofibrous scaffolds endowed with MC extract proved to be an effective therapeutic material for skin wound dressing applications.

Aramid nanofibers reinforced polyvinyl alcohol/tannic acid hydrogel with improved mechanical and antibacterial properties for potential application as wound dressing

The poor mechanical properties and the lack of antibacterial ability of hydrogels limit their applications as wound dressing. In this work, a novel and high strength polyvinyl alcohol (PVA)/tannic acid (TA) hydrogel with aramid nanofibers (ANFs) as the reinforcement was successfully fabricated. The surface composition and microstructure of the hydrogel were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The mechanical properties, water content and swelling behaviors, as well as the antibacterial abilities and biocompatibility of the prepared hydrogel were systematically analyzed as well. The results indicated that the prepared hydrogel showed excellent mechanical properties. The tensile strength and elongation of the prepared hydrogel can respectively reach 2.06 MPa and 950% owing to the formation of the multiple H bonds among PVA, ANFs and TA. What's more, PVA/ANFs/TA (PAT) hydrogel possessed shape memory and broad-spectrum antibacterial properties against S. aureus, E. coli and P. aeruginosa (100% antibacterial rate) at the concentration of 12 mg/mL. PAT hydrogels also had low cytotoxicity, affirming its potential application as wound dressing.