Antimicrobial Wound Dressings as Potential Materials for Skin Tissue Regeneration

Electrospun Antimicrobial Drug Delivery Systems and Hydrogels Used for Wound Dressings

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

Composites based on alginate containing formylphosphazene-crosslinked chitosan and its Cu(II) complex as an antibiotic-free antibacterial hydrogel dressing with enhanced cytocompatibility

Hydrogels based on chitosan or alginate biopolymers are believed to be desirable for covering skin lesions. In this research, we explored the potential of a new composite hydrogels series of sodium alginate (Alg) filled with cross-linked chitosan to use as hydrogel wound dressings. Cross-linked chitosan (CSPN) was synthesized by Schiff-base reaction with aldehydated cyclophosphazene, and its Cu(II) complex was manufactured and identified. Then, their powder suspension and Alg were transformed into hydrogel via ion-crosslinking with Ca2+. The hydrogel constituents were investigated by using FTIR, XRD, rheological techniques, and thermal analysis including TGA (DTG) and DSC. Moreover, structure optimization calculations were performed with the Material Studio 2017 program based on DFT-D per Dmol3 module. Examination of Alg's interactions with CSPN and CSPN-Cu using this module demonstrated that Alg molecules can be well adsorbed to the particle's surface. By changing the dosage of CSPN and CSPN-Cu, the number and size of pores, swelling rate, degradation behavior, protein absorption rate, cytotoxicity and blood compatibility were changed significantly. Subsequently, we employed erythromycin as a model drug to assess the entrapment efficiency, loading capacity, and drug release rate. FITC staining was selected to verify the hydrogels' intracellular uptake. Assuring the cytocompatibility of Alg-based hydrogels was approved by assessing the survival rate of fibroblast cells using MTT assay. However, the presence of Cu(II) in the developed hydrogels caused a significant antibacterial effect, which was comparable to the antibiotic-containing hydrogels. Our findings predict these porous, biodegradable, and mechanically stable hydrogels potentially have a promising future in the wound healing as antibiotic-free antibacterial dressings.

Crosslinked carboxymethyl cellulose colloidal solution for cotton thread coating in wound dressing: A rheological study

Cotton thread therapeutic properties as a wound dressing can be enhanced by utilising carboxymethyl cellulose-nanoparticles (CMC/NPs) colloidal solution as a coating solution. Nanoparticles such as graphene oxide (GO), graphene quantum dots (GQD), and silver nanoparticles (AgNP) stability in CMC was investigated through the rheological analysis and UV-Vis spectroscopy of the colloidal solutions. Citric acid (CA) acted as a crosslinker and was utilised to crosslink the colloidal solution with cotton thread. These CMC/NPs coated threads were subjected to mechanical properties and antibacterial activity analysis. Results obtained indicate less nanoparticle agglomeration and were stable in the CMC-based nanofluid. CMC/NPs rheological study suggested that colloidal solutions exhibited shear thinning behaviour and behaved as non-Newtonian fluids with n < 1. Crosslinked CMC/NPs appeared in a gel-like state as the viscoelasticity of the solution increased. Among the colloidal solutions, CMC/AgNP showed the highest enhancement with a significant difference at p < 0.05 in terms of mechanical and antibacterial properties. Consequently, the rheological properties and stability of CMC/NPs might influence the coating solution's appearance and refine the cotton thread's microstructure for a functional wound dressing to be further utilised as a coating solution for antibacterial cotton thread wound dressing material.

Antibacterial and hemostatic polyvinyl alcohol/microcrystalline cellulose reinforced sodium alginate breathable dressing containing Euphorbia humifusa extract based on microfluidic spinning technology

Antibacterial hemostatic medical dressings have become feasible solutions in response to the challenging wound-healing process. In this study, a novel fiber-type medical dressing with excellent breathable, antibacterial, and hemostatic qualities was created using sodium alginate (SA), microcrystalline cellulose (MCC), polyvinyl alcohol (PVA), and Euphorbia humifusa Willd (EHW) based on microfluidic spinning technology, and the properties of the dressing were characterized. The orthogonal test demonstrates that PVA and MCC can enhance the mechanical properties of the fiber, which is a crucial requirement for fiber assembly to form the dressing. Moreover, the presence of EHW enhances the dressing's antibacterial and hemostatic qualities. The dressings have been proven to have potent antibacterial and hemostatic properties as well as the ability to considerably speed up wound healing and skin tissue regeneration in the in-vitro and in-vivo tests. In conclusion, this innovative fiber-type medical dressing containing SA, MCC, PVA, and EHW has enormous potential for managing wounds caused by bacteria.

Silver nanoparticles modified hFGF2-linking camelina oil bodies accelerate infected wound healing

Bacterial infection wounds are common in life. At present, although various wound materials have shown antibacterial activity, there is a lack of overall strategy to promote wound healing. Therefore, it is necessary to develop multifunctional wound materials. In this study, silver nanoparticles (Ag NPs) modified camelina oil bodies (OB) which surface covalently bonded human fibroblast growth factor 2 (Ag NPs-hFGF2-OB) were designed for the treatment of bacterial infection wounds. The prepared Ag NPs-hFGF2-OB not only act as an antibacterial agent to realize sterilization, but also act as a tissue repair agent that effectively promotes wound healing. Ag⁺ was reduced in situ to Ag NPs by ascorbic acid, and the activity of hFGF2 protein was not affected after hFGF2-OB was modified by Ag NPs, which displaying broad apectrum antibacterial ability for both S. aureus and E. coli, with an antibacterial rate of more than 70 % (the concentration of Ag NPs was 20 μg/mL, the hFGF2 protein concentration was 20 µg/mL). Ag NPs-hFGF2-OB can effectively promote the migration of NIH/3T3 cells, showing good biocompatibility. The mouse bacterial infection wound model experiments proved that the wound healing rate of Ag NPs-hFGF2-OB group (the concentration of Ag NPs was 20 μg/mL, the hFGF2 protein concentration was 20 µg/mL) was much higher than other treatment groups, especially on the 7th day after treatment, the wound healing rate reached 71.71 ± 2.38 %, while the healing rate of other treatment groups were only 34.54 ± 1.10 %, 37.08 ± 2.85 % and 47.99 ± 2.01 %. Therefore, Ag NPs-hFGF2-OB, which can inhibit bacterial growth, promotes collagen deposition, granulation tissue regeneration and angiogenesis without any significant toxicity, shows good potential for application in the repair of bacterial infection wounds.

Thermally Treated Berberine-Loaded SA/PVA/PEO Electrospun Microfiber Membranes for Antibacterial Wound Dressings

This study aimed to develop a safe and advanced antibacterial material of electrospun microfiber membranes (MFMs) for wound dressings. Combinations of several materials were investigated; thermal treatment and electrospinning techniques were used to form the best quality of MFMs to suit its end applications. By comparing the fiber morphology, diameter changes, and fracture strength, the suitable ratio of raw materials and thermal treatment were obtained before and after adding Trition X-100 as a surfactant for MFMs of sodium alginate/polyvinyl alcohol/polyethylene oxide (SA/PVA/PEO). The electrospinning solution was mixed with berberine as an antibacterial substance; meanwhile, calcium chloride (CaCl₂) was used as the crosslinking agent. The antibacterial properties, water dissolution resistance, water content, and fracture strength were thoroughly investigated. The results showed that the antibacterial rates of MFMs with different mass fractions of berberine (0, 3, and 5 wt.%) to Escherichia coli (E. coli) were 14.7, 92.9, and 97.2%, respectively. The moisture content and fracture strength of MFMs containing 5 wt.% berberine were 72.0% and 7.8 MPa, respectively. In addition, the produced MFMs embodied great water dissolution resistance. Berberine-loaded SA/PVA/PEO MFMs could potentially serve as an antibacterial wound dressing substrate with low cost and small side effects.

Fabrication of Poly(vinyl alcohol)/Chitosan Composite Films Strengthened with Titanium Dioxide and Polyphosphonate Additives for Packaging Applications

Eco-innovation through the development of intelligent materials for food packaging is evolving, and it still has huge potential to improve food product safety, quality, and control. The design of such materials by the combination of biodegradable semi-synthetic polymers with natural ones and with some additives, which may improve certain functionalities in the targeted material, is continuing to attract attention of researchers. To fabricate composite films via casting from solution, followed by drying in atmospheric conditions, certain mass ratios of poly(vinyl alcohol) and chitosan were used as polymeric matrix, whereas TiO2 nanoparticles and a polyphosphonate were used as reinforcing additives. The structural confirmation, surface properties, swelling behavior, and morphology of the xerogel composite films have been studied. The results confirmed the presence of all ingredients in the prepared fabrics, the contact angle of the formulation containing poly(vinyl alcohol), chitosan, and titanium dioxide in its composition exhibited the smallest value (87.67°), whereas the profilometry and scanning electron microscopy enlightened the good dispersion of the ingredients and the quality of all the composite films. Antimicrobial assay established successful antimicrobial potential of the poly(vinyl alcoohol)/chitosan-reinforced composites films against Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Cytotoxicity tests have revealed that the studied films are non-toxic, presented good compatibility, and they are attractive candidates for packaging applications.

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.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Bee-Derived Products: Chemical Composition and Applications in Skin Tissue Engineering

Skin tissue regeneration is one of the population's most common problems, and the complications that may appear in the healing process can have detrimental consequences. An alternative to conventional treatments could be represented by sustainable materials based on natural products, such as honey and its derivates (propolis, royal jelly, bee pollen, beeswax, and bee venom). They exhibit significant inhibitory activities against bacteria and have great potential in dermal tissue regeneration. Research in the pharmaceutical field demonstrates that conventional medication combined with bee products can deliver better results. The advantages include minimizing side effects and maintaining the same effectiveness by using low concentrations of antibiotic, anti-inflammatory, or chemotherapy drugs. Several studies suggested that bee products can replace the antimicrobial activity and efficiency of antibiotics, but further investigation is needed to establish a topical mixture's potential, including honey, royal jelly, and propolis. Bee products seem to complete each other's deficiencies, and their mixture may have a better impact on the wound healing process. The topic addressed in this paper highlights the usefulness of honey, propolis, royal jelly, bee pollen, beeswax, and bee venom in the re-epithelization process and against most common bacterial infections.

Chitosan nanofiber biocomposites for potential wound healing applications: Antioxidant activity with synergic antibacterial effect

Bacterial wound infection is one of the most common nosocomial infections. The unnecessary employment of antibiotics led to raising the growth of antibiotic-resistant bacteria. Accordingly, alternative armaments capable of accelerating wound healing along with bactericidal effects are urgently needed. Considering this, we fabricated chitosan (CS)/polyethylene oxide (PEO) nanofibers armed with antibacterial silver and zinc oxide nanoparticles. The nanocomposites exhibited a high antioxidant effect and antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Besides, based on the results of the cell viability assays, the optimum concentration of ZnONPs and AgNPs in the nanofibrous mats is 0.2% w/v and 0.08% w/v respectively and had no cytotoxicity on fibroblast cells. The scaffold also showed good blood compatibility according to the effects of coagulation time. As well as significant fibroblast migration and proliferation on the wound margin, according to wound-healing assay. All in all, the developed biocompatible, antioxidant, and antibacterial Ag-ZnO NPs incorporated CS/PEO nanofibrous mats showed their potential as an effective wound dressing.

Antimicrobial properties of a new polymeric material based on poly(2-hydroxyethyl methacrylate)

BACKGROUND AND AIM

Оne of the promising areas is the development of synthetic wound dressings with programmed release of active substances that can affect various elements in the pathogenesis of the wound process. The aim was to study the antimicrobial properties of a new polymeric material based on poly(2-hydroxyethyl methacrylate).

METHODS

2-hydroxyethyl methacrylate, dimethacrylate triethylene glycol as crosslinking agent, polymerization initiator of azobisizobutyronitrile along with a porogen and one of the antimicrobial agents, including decamethoxin, chlorhexidine bigluconate, silver nitrate, octenidine, furacilin, metronidazole, dioxidine, and gentamicin were used to synthesize a new material with antimicrobial activity. For comparison, polymer samples synthesized without adding antimicrobials were used, as well as known dressing materials: carbon material, porcine skin, which were immersed into 0.02% decamethoxin solution before use, as well as silver-containing dressing, hydrogel dressings, including those filled with silver. Determination of antibacterial properties was performed by diffusionmethod.

RESULTS

Low antimicrobial activity of the studied existing wound dressings, which are widely used in medical practice, even under conditions of their saturation with antiseptic substances, has been established. Samples of the suggested polymeric material with the addition of antimicrobial substances showed the ability to inhibit the growth of the test strains of microorganisms at a sufficient level, especially with such fillers as decamethoxin, gentamicin, dioxidine. When metronidazole was added to the polymeric material, a reliable antimicrobial effect on the anaerobic microorganisms was established.

CONCLUSIONS

Modification of the polymeric material of poly(2-hydroxyethyl methacrylate) by adding antimicrobial substances allows to ensure its high antimicrobial properties against different microorganisms.

Bioactive Collagen Hydrolysate-Chitosan/Essential Oil Electrospun Nanofibers Designed for Medical Wound Dressings

In this study, lemon balm (Melissa officinalis L.) and dill (Anethum graveolens L.) essential oils (EOs) were encapsulated into collagen hydrolysates extracted from bovine tendons and rabbit skins, both mixed with chitosan (CS) by using the coaxial electrospinning technique for potential wound dressing applications. The morphology and chemical composition of the electrospun nanofibers were investigated using scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The antimicrobial activity of the dill EO and lemon EO, as well as the electrospun samples loaded with essential oils was determined by disk diffusion assay against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, and Salmonella typhimurium ATCC 14028 bacterial strains; Candida albicans ATCC 10231 and Candida glabrata ATCC 90028 yeast strains; and Aspergillus brasiliensis ATCC 9642 fungal strain. In vivo biocompatibility testing of the collagen hydrolysate-chitosan/essential oil electrospun nanofibers was based on the determination of the hematological, biochemical, and immunological profile and the evaluation of the influence produced on the oxidative stress in white Swiss mice. The synergetic effect of dill and lemon balm EOs can improve the antimicrobial activity of collagen hydrolysate-chitosan nanofibers against the most important bacterial strains. The in vivo test results suggested a good biocompatibility of electrospun samples based on collagen hydrolysate extracted from bovine tendons or rabbit skin mixed with chitosan and containing dill and/or lemon balm essential oils as encapsulated bioactive compounds.

A synergy between dopamine and electrostatically bound bactericide in a poly (vinyl alcohol) hybrid hydrogel for treating infected wounds

Antibacterial hydrogels have emerged as viable options for battling infections associated with impaired wound healing. It is challenging in developing antibacterial hydrogels that have sustained and stable bactericidal activity while avoiding the use of any agents that may adversely affect safety. In view of this concern, a multi-functional polyvinyl alcohol (PVA)/sodium alginate-dopamine (SA-DA) hydrogel matrix-based wound dressing embedding with bis-quaternary triphenyl-phosphonium salt (BTPP+), that would present long-term intrinsic antimicrobial properties was developed using freeze-thawing (F-T) method herein. DA endows the hydrogel with efficient bacteria capture ability and subsequently the captured bacterial pathogens were in situ killed by electrostatically bound BTPP+, and hence significantly augmented the antibacterial efficacy. Furthermore, DA, co-operating with BTPP+ could promote erythrocyte and platelet aggregation on hydrogels, which ensures hydrogels with improved hemostasis capacity. Thus, this investigation provides a feasible simple avenue for development of long-term intrinsic antimicrobial hydrogel dressings with efficient hemostasis efficacy for infected wounds.

Influence of Terbium Ions and Their Concentration on the Photoluminescence Properties of Hydroxyapatite for Biomedical Applications

A new generation of biomaterials with terbium-doped hydroxyapatite was obtained using a coprecipitation method. The synthesis of new materials with luminescent properties represents a challenging but important contribution due to their potential applications in biomedical science. The main objective of this study was to revel the influence of terbium ions on the design and structure of hydroxyapatite. Different concentrations of terbium, described by the chemical formula Ca_10−xTb_x(PO₄)₆(OH)₂, where x is in the range of 0 to 1, were considered. The consequence of ion concentration on hydroxyapatite morphology was also investigated. The morphology and structure, as well as the optical properties, of the obtained nanomaterials were characterized using X-ray powder diffraction analysis (XRD), Fourier Transform Infrared spectrometry (FTIR), SEM and TEM microscopy, UV-Vis and photoluminescence spectroscopies. The measurements revealed that terbium ions were integrated into the structure of hydroxyapatite within certain compositional limits. The biocompatibility and cytotoxicity of the obtained powders evaluated using MTT assay, oxidative stress assessment and fluorescent microscopy revealed the ability of the synthesized nanomaterials to be used for biological system imaging.

Antibacterial Biodegradable Films Based on Alginate with Silver Nanoparticles and Lemongrass Essential Oil-Innovative Packaging for Cheese

Replacing the petroleum-based materials in the food industry is one of the main objectives of the scientists and decision makers worldwide. Biodegradable packaging will help diminish the environmental impact of human activity. Improving such biodegradable packaging materials by adding antimicrobial activity will not only extend the shelf life of foodstuff, but will also eliminate some health hazards associated with food borne diseases, and by diminishing the food spoilage will decrease the food waste. The objective of this research was to obtain innovative antibacterial films based on a biodegradable polymer, namely alginate. Films were characterized by environmental scanning electron microscopy (ESEM), Fourier-transform infrared spectroscopy (FTIR) and microscopy, complex thermal analysis (TG-DSC-FTIR), UV-Vis and fluorescence spectroscopy. Water vapor permeability and swelling behavior were also determined. As antimicrobial agents, we used silver spherical nanoparticles (Ag NPs) and lemongrass essential oil (LGO), which were found to act in a synergic way. The obtained films exhibited strong antibacterial activity against tested strains, two Gram-positive (Bacillus cereus and Staphylococcus aureus) and two Gram-negative (Escherichia coli and Salmonella Typhi). Best results were obtained against Bacillus cereus. The tests indicate that the antimicrobial films can be used as packaging, preserving the color, surface texture, and softness of cheese for 14 days. At the same time, the color of the films changed (darkened) as a function of temperature and light presence, a feature that can be used to monitor the storage conditions for sensitive food.

Synthesis and Characterization of Photoluminescent Ce(III) and Ce(IV) Substituted Hydroxyapatite Nanomaterials by Co-Precipitation Method: Cytotoxicity and Biocompatibility Evaluation

Improved compounds of Ce(III) and Ce(IV)-doped hydroxyapatite (Ca_10-xCe_x(PO₄)₆(OH)₂) with different concentrations such as x = 0.5, 1, 2.5, 5, and 10%, obtained by the simple co-precipitation method were synthesized. The cerium (3⁺) and cerium (4⁺)-doped hydroxyapatite were evaluated for biocompatibility and fluorescence properties. It was found that the cerium-HAp powders were non-toxic, even at higher level of concentration. The synthesized powders were further characterized by FTIR spectrometry, UV-Vis spectroscopy, XRD diffraction, SEM and TEM analysis. Therefore, the present study proves that the developed cerium (3⁺) and cerium (4⁺)-doped hydroxyapatite, respectively can be widely used as luminescent labeling materials, with improved biological properties.

Biodegradable Alginate Films with ZnO Nanoparticles and Citronella Essential Oil-A Novel Antimicrobial Structure

The petroleum-based materials could be replaced, at least partially, by biodegradable packaging. Adding antimicrobial activity to the new packaging materials can also help improve the shelf life of food and diminish the spoilage. The objective of this research was to obtain a novel antibacterial packaging, based on alginate as biodegradable polymer. The antibacterial activity was induced to the alginate films by adding various amounts of ZnO nanoparticles loaded with citronella (lemongrass) essential oil (CEO). The obtained films were characterized, and antibacterial activity was tested against two Gram-negative (Escherichia coli and Salmonella Typhi) and two Gram-positive (Bacillus cereus and Staphylococcus aureus) bacterial strains. The results suggest the existence of synergy between antibacterial activities of ZnO and CEO against all tested bacterial strains. The obtained films have a good antibacterial coverage, being efficient against several pathogens, the best results being obtained against Bacillus cereus. In addition, the films presented better UV light barrier properties and lower water vapor permeability (WVP) when compared with a simple alginate film. The preliminary tests indicate that the alginate films with ZnO nanoparticles and CEO can be used to successfully preserve the cheese. Therefore, our research evidences the feasibility of using alginate/ZnO/CEO films as antibacterial packaging for cheese in order to extend its shelf life.

Synthesis of a novel nanocomposite containing chitosan as a three-dimensional printed wound dressing technique: Emphasis on gene expression

In this study, a highly porous three-dimensional (3D)-printed wound healing core/shell scaffold fabricated using poly-lactic acid (PLA). The core of scaffold was composed of hyaluronic acid (HA), copper carbon dots (Cu-CDs), rosmarinic acid, and chitosan hydrogel. Cu-CDs were synthesized using ammonium hydrogen citrate under hydrothermal conditions. Formulation containing 1 mg ml^-1 concentration of Cu-CDs showed an excellent antibacterial activity against gram bacteria. At 0.25 mg ml^-1 of Cu-CDs concentration, scaffold had a good biocompatibility as confirmed by cytotoxicity assay on L929 fibroblast stem cells. in vivo wound healing experiments on groups of rats revealed that after 15 days of treatment, the optimal formulation of composite scaffold significantly improves the wound healing process compared to the PLA scaffold. This finding was confirmed by histological analysis and the relative expression of PDGF, TGF-β, and MMP-1 genes. The biocompatible antibacterial CU-CDS/PLA/HA/chitosan/rosmarinic acid nanocomposite is a promising wound healing scaffold which highly accelerates the process of skin regeneration.

Nanofiller-Enhanced Soft Non-Gelatin Alginate Capsules for Modified Drug Delivery

Capsules are one of the major solid dosage forms available in a variety of compositions and shapes. Developments in this dosage form are not new, but the production of non-gelatin capsules is a recent trend. In pharmaceutical as well as other biomedical research, alginate has great versatility. On the other hand, the use of inorganic material to enhance material strength is a common research topic in tissue engineering. The research presented here is a combination of qualities of alginate and montmorillonite (MMT). These two materials were used in this research to produce a soft non-gelatin modified-release capsule. Moreover, the research describes a facile benchtop production of these capsules. The produced capsules were critically analyzed for their appearance confirming resemblance with marketed capsules, functionality in terms of drug encapsulation, as well as release and durability.

Collagen-Carboxymethylcellulose Biocomposite Wound-Dressings with Antimicrobial Activity

Microbial infections associated with skin diseases are frequently investigated since they impact on the progress of pathology and healing. The present work proposes the development of freeze-dried, glutaraldehyde cross-linked, and non-cross-linked biocomposite dressings with a porous structure, which may assist the reepithelization process through the presence of collagen and carboxymethylcellulose, along with a therapeutic antimicrobial effect, due to silver nanoparticles (AgNPs) addition. Phisyco-chemical characterization revealed the porous morphology of the obtained freeze-dried composites, the presence of high crystalline silver nanoparticles with truncated triangular and polyhedral morphologies, as well as the characteristic absorption bands of collagen, silver, and carboxymethylcellulose. In vitro tests also assessed the stability, functionality, and the degradability rate of the obtained wound-dressings. Antimicrobial assay performed on Gram-negative (Escherichia coli), Gram-positive (Staphyloccocus aureus) bacteria, and yeast (Candida albicans) models demonstrated that composite wound dressings based on collagen, carboxymethylcellulose, and AgNPs are suitable for skin lesions because they prevent the risk of infection and have prospective wound healing capacity. Moreover, the cell toxicity studies proved that the obtained materials can be used in long time treatments, with no cytotoxic effects.

Multifunctional mats by antimicrobial nanoparticles decoration for bioinspired smart wound dressing solutions

Developing advanced materials for wound dressings is a very challenging, yet unaddressed task. These systems are supposed to act as temporary skin substitutes, performing multiple functions, including fluid absorption and antimicrobial action, supporting cell proliferation and migration in order to promote the skin regeneration process. Following a global bioinspired approach, in this study, we developed a multifunctional textile for wound dressing applications. Biodegradable polyhydroxybutyrate/poly-3-caprolactone (PHB/PCL) mats were fabricated by electrospinning to mimic the extracellular matrix (ECM), thus providing structural and biochemical support to tissue regeneration. Furthermore, inspired by nature's strategy which exploits melanin as an effective weapon against pathogens infection, PHB/PCL mats were modified with hybrid Melanin-TiO₂ nanostructures. These were combined to PHB/PCL mats following two different strategies: in-situ incorporation during electrospinning process, alternately ex-post coating by electrospraying onto obtained mats. All samples revealed huge water uptake and poor cytotoxicity towards HaCat eukaryotic cells. Melanin-TiO₂ coating conferred PHB/PCL mats significant antimicrobial activity towards both Gram(+) and Gram(-) strains, marked hydrophilic properties as well as bioactivity which is expected to promote materials-cells interaction. This study is going to provide a novel paradigm for the design of active wound dressings for regenerative medicine.

Recent Advances in Zinc Oxide Nanostructures with Antimicrobial Activities

This article reviews the recent developments in the synthesis, antibacterial activity, and visible-light photocatalytic bacterial inactivation of nano-zinc oxide. Polycrystalline wurtzite ZnO nanostructures with a hexagonal lattice having different shapes can be synthesized by means of vapor-, liquid-, and solid-phase processing techniques. Among these, ZnO hierarchical nanostructures prepared from the liquid phase route are commonly used for antimicrobial activity. In particular, plant extract-mediated biosynthesis is a single step process for preparing nano-ZnO without using surfactants and toxic chemicals. The phytochemical molecules of natural plant extracts are attractive agents for reducing and stabilizing zinc ions of zinc salt precursors to form green ZnO nanostructures. The peel extracts of certain citrus fruits like grapefruits, lemons and oranges, acting as excellent chelating agents for zinc ions. Furthermore, phytochemicals of the plant extracts capped on ZnO nanomaterials are very effective for killing various bacterial strains, leading to low minimum inhibitory concentration (MIC) values. Bioactive phytocompounds from green ZnO also inhibit hemolysis of Staphylococcus aureus infected red blood cells and inflammatory activity of mammalian immune system. In general, three mechanisms have been adopted to explain bactericidal activity of ZnO nanomaterials, including direct contact killing, reactive oxygen species (ROS) production, and released zinc ion inactivation. These toxic effects lead to the destruction of bacterial membrane, denaturation of enzyme, inhibition of cellular respiration and deoxyribonucleic acid replication, causing leakage of the cytoplasmic content and eventual cell death. Meanwhile, antimicrobial activity of doped and modified ZnO nanomaterials under visible light can be attributed to photogeneration of ROS on their surfaces. Thus particular attention is paid to the design and synthesis of visible light-activated ZnO photocatalysts with antibacterial properties.

Recent trends on wound management: New therapeutic choices based on polymeric carriers

Wound healing is an unmet therapeutic challenge among medical society since wound assessment and management is a complex procedure including several factors playing major role in healing process. Wounds can mainly be categorized as acute or chronic. It is well referred that the acute wound displays normal wound physiology while healing, in most cases, is seemed to progress through the normal phases of wound healing. On the other hand, a chronic wound is physiologically impaired. The main problem in wound management is that the majority of wounds are colonized with microbes, whereas this does not mean that all wounds will be infected. In this review, we address the problems that clinicians face to manage while treat acute and chronic wounds. Moreover, we demonstrate the pathophysiology, etiology, prognosis and microbiology of wounds. We further introduce the state of art in pharmaceutical technology field as part of wound management aiming to assist health professionals to overcome the current implications on wound assessment. In addition, authors review researches which included the use of gels and dermal films as wound healing agents. It can be said that natural and synthetic drugs or carriers provide promising solutions in order to meet the wound management standards. However, are the current strategies as desirable as medical society wish?

Regenerative Wound Dressings for Skin Cancer

Skin cancer is considered the most prevalent cancer type globally, with a continuously increasing prevalence and mortality growth rate. Additionally, the high risk of recurrence makes skin cancer treatment among the most expensive of all cancers, with average costs estimated to double within 5 years. Although tumor excision is the most effective approach among the available strategies, surgical interventions could be disfiguring, requiring additional skin grafts for covering the defects. In this context, post-surgery management should involve the application of wound dressings for promoting skin regeneration and preventing tumor recurrence and microbial infections, which still represents a considerable clinical challenge. Therefore, this paper aims to provide an up-to-date overview regarding the current status of regenerative wound dressings for skin cancer therapy. Specifically, the recent discoveries in natural biocompounds as anti-cancer agents for skin cancer treatment and the most intensively studied biomaterials for bioactive wound dressing development will be described.

Electrospun Nano-Fibers for Biomedical and Tissue Engineering Applications: A Comprehensive Review

Pharmaceutical nano-fibers have attracted widespread attention from researchers for reasons such as adaptability of the electro-spinning process and ease of production. As a flexible method for fabricating nano-fibers, electro-spinning is extensively used. An electro-spinning unit is composed of a pump or syringe, a high voltage current supplier, a metal plate collector and a spinneret. Optimization of the attained nano-fibers is undertaken through manipulation of the variables of the process and formulation, including concentration, viscosity, molecular mass, and physical phenomenon, as well as the environmental parameters including temperature and humidity. The nano-fibers achieved by electro-spinning can be utilized for drug loading. The mixing of two or more medicines can be performed via electro-spinning. Facilitation or inhibition of the burst release of a drug can be achieved by the use of the electro-spinning approach. This potential is anticipated to facilitate progression in applications of drug release modification and tissue engineering (TE). The present review aims to focus on electro-spinning, optimization parameters, pharmacological applications, biological characteristics, and in vivo analyses of the electro-spun nano-fibers. Furthermore, current developments and upcoming investigation directions are outlined for the advancement of electro-spun nano-fibers for TE. Moreover, the possible applications, complications and future developments of these nano-fibers are summarized in detail.

Biocompatible Ag/Fe-Enhanced TiO2 Nanoparticles as an Effective Compound in Sunscreens

In this work, valuable biocompatible Ag/Fe-enhanced TiO2 nanoparticles are comparatively prepared by a conventional wet chemistry method (sol-gel) and a rapid, efficient, hybrid unconventional method (microwave-assisted hydrothermal synthesis). In order to establish their application as effective compounds in sunscreens, the obtained powders were first structurally and morphologically characterized, analyses from which their nanodimensional character, crystalline structure and thermal behavior were highlighted. The evaluation of sunscreen effectiveness is based on the determination of the sun protection factor (SPF). It was observed that silver enhancing increases the SPF significantly, especially when compared to the pristine samples. The obtained Ag/Fe-enhanced TiO2 powders were also evaluated from the point of view of their biocompatibility on amniotic fluid stem cells, and the results indicated an enhance of cell proliferation when exposed to the synthesized nanostructures.

Antibiotic Delivery Strategies to Treat Skin Infections When Innate Antimicrobial Defense Fails

The epidermal skin barrier protects the body from a host of daily challenges, providing protection against mechanical insults and the absorption of chemicals and xenobiotics. In addition to the physical barrier, the epidermis also presents an innate defense against microbial overgrowth. This is achieved through the presence of a diverse collection of microorganisms on the skin (the "microbiota") that maintain a delicate balance with the host and play a significant role in overall human health. When the skin is wounded, the local tissue with a compromised barrier can become colonized and ultimately infected if bacterial growth overcomes the host response. Wound infections present an immense burden in healthcare costs and decreased quality of life for patients, and treatment becomes increasingly important because of the negative impact that infection has on slowing the rate of wound healing. In this review, we discuss specific challenges of treating wound infections and the advances in drug delivery platforms and formulations that are under development to improve topical delivery of antimicrobial treatments.

Antibacterial Activity and Biodegradation of Cellulose Fiber Blends with Incorporated ZnO

This research aimed to study the influence of lyocell with incorporated ZnO (CLY) for antibacterial activity and biodegradation of fiber blends composed of viscose (CV), flax (LI), and CLY. Fiber blended samples with an increased weight fraction of CLY fibers were composed, and single CLY, CV and LI fibers were also used for comparison. Antibacterial activity was determined for the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus bacteria. The biodegradation of fiber blends was investigated by the soil burial test. The results show that the single CLY fibers exhibited high antimicrobial activity against both E. coli and S. aureus bacteria and that the presence of LI fibers in the blended samples did not significantly affect antibacterial activity against E. coli, but drastically decreased the antibacterial activity against S. aureus. LI fibers strongly promoted the growth of S. aureus and, consequently, impaired the antimicrobial performance of ZnO against this bacterium. The presence of CLY fibers slowed down, but did not prevent, the biodegradation process of the fiber blends, even at the highest ZnO concentration. The soil that was in contact with the fiber blended samples during their burial was not contaminated to such an extent as to affect the growth of sprouts, confirming the sustainability of the fiber blends.