Properties Of Wound Dressings Research Articles

Antimicrobial and antihemolytic properties of a CNF/AgNP-chitosan film: A potential wound dressing material

Cellulose nanofibers (CNFs), chitosan, and silver nanoparticles (AgNPs) are widely used to enhance the active functions and antibacterial properties of wound dressings. This study was conducted to prepare CNF/AgNP-chitosan using a straight incorporation method and to assess its antimicrobial activity. CNFs were isolated from oil palm empty fruit bunches (OPEFBs) using the pulping method and acid hydrolysis. AgNPs were synthesized using a green synthesis method. The wound dressing was produced by mixing a 10% CNF solution in LiCl/DMAc and AgNP-chitosan in a glass plate with various ratios of CNF/AgNP-chitosan, i.e., 100:0, 80:20, 60:40, and 50:50. UV-visible and TEM analyses were conducted to confirm the formation of AgNPs and CNFs at the nanoscale. The results showed particles with an absorption wavelength of 435 nm and spherical shapes. Based on the calculation using ImageJ software, the diameters of CNFs were approximately 50 nm, and the lengths were several micrometers. FTIR was used to analyze the chemical bonding of AgNP-chitosan and the incorporated AgNP-chitosan in CNFs. Based on the XRD analysis, the presence of AgNPs did not affect the crystallinity of the CNFs. SEM images showed that the addition of AgNPs resulted in the stretching of CNF pores on the pads. Thermal degradation of the film increased with the addition of AgNP-chitosan by up to 40%. Antimicrobial tests and hemocompatibility tests showed that the formed CNF/AgNP-chitosan film successfully inhibited bacterial growth and was classified as a nonhemolytic material; thus, its potential as a wound dressing should be further studied.

Development of a methodology for the study of polymer wound coatings for application characteristics

This paper reports a research methodology for characterizing wound dressings in order to assess the application properties of medical devices as a whole. Wound dressing was based on grafting polymerization of N-vinyl caprolactam and 2-hydoxyethyl acrylate on polyvinyl alcohol. The obtained copolymer was characterized by FTIR. Cross-linked films of wound dressings were obtained by radiation treatment of the copolymers. The physico-mechemical properties of wound dressings were investigated. Testing included degree of swelling, elastic modulus, tensile strength and elongation at break. The radiation doses of the reaction affected physico-mechanical properties of wound dressings. As the dose of radiation increased, the yield of gel increased, degree of swilling and tensile strength decreased. Also, the results indicated that the yield of the crosslinked fraction increases, and the swelling capacity of polymer mesh decreases with increasing 2-hydroxyethyl acrylate content in the graft copolymer

Photodegradable Hydrogels for Cell Encapsulation and Tissue Adhesion

Hydrogels for wound management and tissue gluing applications have to adhere to tissues for a given time scale and then disappear, either by removal from the skin or by slow degradation for applications inside the body. Advanced wound management materials also envision the encapsulation of therapeutic drugs or cells to support the natural healing process. The design of hydrogels that can fulfill all of these properties with minimal chemical complexity, a stringent condition to favor transfer into a real medical device, is challenging. Herein, we present a hydrogel design with a moderate structural complexity that fulfills a number of relevant properties for wound dressing: it can form in situ and encapsulate cells, it can adhere to tissues, and it can be degraded on demand by light exposure under cytocompatible conditions. The hydrogels are based on starPEG macromers terminated with catechol groups as cross-linking units and contain intercalated photocleavable nitrobenzyl triazole groups. Hydrogels are formed under mild conditions (N-(2-hydroxyethyl)piperazine-N'-ethanesulfonic acid (HEPES) buffer with 9-18 mM sodium periodate as the oxidant) and are compatible with encapsulated cells. Upon light irradiation, the cleavage of the nitrobenzyl group mediates depolymerization, which enables the on-demand release of cells and debonding from tissues. The molecular design and obtained properties reported here are interesting for the development of advanced wound dressings and cell therapies and expand the range of functionality of current alternatives.

Natural Inorganic Ingredients in Wound Healing.

One of the major clinical challenges is to achieve a rapid and efficient treatment of complex chronic wounds. Nowadays, most wound dressings currently available are unable to find a solution to the challenges of resistance to bacterial infection, protein adsorption and increased levels of exudates. Natural inorganic ingredients (clay minerals, metal cations, zeolites, etc.) could be the key to solve the problem satisfactorily. Some of these materials have shown biocompatibility and ability to enhance cell adhesion, proliferation and cellular differentiation and uptake. Besides, some natural inorganic ingredients effectively retain drugs, allowing the design of drug delivery matrices. Possibilities of natural inorganic ingredients in wound healing treatments have been reviewed, the following sections have been included: 1. Introduction 2. Functions of Inorganic Ingredients in wound healing 2.1. Antimicrobial effects 2.2. Hemostatic effects 3. Clay minerals for wound healing 3.1. Clay minerals 3.2. Clay mineral semisolid formulations 3.3. Clay/polymer composites and nanocomposites 3.4. Clay minerals in wound dressings 4. Other inorganic materials for wound healing 4.1. Zeolites 4.2. Silica and other silicates 4.3. Other minerals 4.4. Transition metals 5. Conclusion. Inorganic ingredients possess useful features for the development of chronic wounds advanced treatments. They improve physical (mechanical resistance and water vapor transmission), chemical (release of drugs, hemostasis and/or adsorption of exudates and moisture) and biological (antimicrobial effects and improvement of healing) properties of wound dressings. In summary, inorganic ingredients have proved to be a promising and easily accessible products in the treatment of wounds and, more importantly, chronic wounds.

First-Line Interactive Wound Dressing Update: A Comprehensive Review of the Evidence.

Wound management is a significant and growing issue worldwide. Knowledge of dressing products and clinical expertise in dressing selection are two major components in holistic wound management to ensure evidence-based wound care. With expanding global market of dressing products, there is need to update clinician knowledge of dressing properties in wound care. Optimal wound management depends on accurate patient assessment, wound diagnosis, clinicians’ knowledge of the wound healing process and properties of wound dressings. We conducted a comprehensive review of the physical properties of wound dressing products, including the advantages and disadvantages, indications and contraindications and effectiveness of first-line interactive/bioactive dressing groups commonly used in clinical practice. These include semipermeable films, foams, hydroactives, alginates, hydrofibers, hydrocolloids, and hydrogels. In making decisions regarding dressing product selection, clinicians need to ensure a holistic assessment of patient and wound etiology, and understand dressing properties when making clinical decisions using wound management guidelines to ensure optimal patient outcomes. This review has highlighted there is lack of high quality evidence and the need for future well designed trials.

Fabrication of Turmeric Powder-Loaded Silk Fibroin Film for Wound Healing Application

Background: Currently silk fibroin is used more and more in the biomedical researches, including a potential research direction in creating wound dressing. Turmeric powder is a natural drug with many properties suitable for treatment of burns such as anti-inflammatory, anti-bacterial, anti-fungal, especially reducing formation of scars. Methods: In this study, sericin is removed from the silk to obtain fibroin fiber. Fibroin fiber and turmeric powder are dissolved by formic acid adding calcium chloride (CaCl2). Created fibroin films (FF) are then evaluated in some characteristics such as surface structure, chemical structure, tensile strength, absorbency, dehydration rate, biodegradation ability, pH determination, preventing bacteria ability and cytotoxicity test. Results: All results indicated that created FF is fulfilled with all the required properties of wound dressings. Conclusions: This study is the first step to creating foundation and orientation for the development of commercial wound dressings.

Modern Wound Dressings and their Application

Introdution: Wound healing is a complex and dynamic process, which requires to be prepared a suitable environment to promote healing process. Wound dressing is one of the most important external factors affecting the wound healing process. With the advancement in technology, more than 1000 types of modern wound dressings have been developed. Wound dressings are either based on natural materials or on the basis of synthetic and chemical materials. In addition to the protective and covering role, which modern wound dressings play, they have a chemical and physical interaction with wound bed addition. They carry antibiotics, drugs and nanoparticles and play an important role in maintaining moisture or hydration the wound; all of these factors can facilitate the wound healing process. In this study, the wound healing process and the properties of wound dressings were presented first and then the types of wound dressings and their applications were investigated. This study, with comprehensive information on the types of modern wound dressings and their advantages and drawbacks, will help a physician in the proper selection of an appropriate wound dressing.

Incorporation of Silver Sulfadiazine into An Electrospun Composite of Polycaprolactone as An Antibacterial Scaffold for Wound Healing in Rats.

Objective Fabrication of an antibiotic-loaded scaffold with controlled release properties for wound dressing is one of tissue engineering challenges. The aim of this study was to evaluate the wound-healing effectiveness of 500-µm thick polycaprolactone (PCL) nanofibrous mat containing silver sulfadiazine (SSD) as an antibacterial agent. Materials and Methods In this experimental study, an electrospun membrane of PCL nanofibrous mat containing 0.3% weight SSD with 500 µm thickness, was prepared. Morphological and thermomechanical characteristics of nanofibers were evaluated. Drug content and drug release properties as well as the surface hydrophobicity of the nanofibrous membrane were determined. Antimicrobial properties and cellular viability of the scaffold were also examined. A full thickness wound of 400 mm2 was created in rats, to evaluate the wound-healing effects of PCL/SSD blend in comparison with PCL and vaseline gas used as the control group. Results SSD at a concentration of 0.3% improved physicochemical properties of PCL. This concentration of SSD did not inhibit the attachment of human dermal fibroblasts (HDFs) to nanofibers in vitro, but showed antibacterial activity against Gram-positive Staphylococcus aureus (ST) and Gram-negative Pseudomonas aeruginosa (PS). Overall, results showed that SSD improves characteristics of PCL nanofibrous film and improves wound-healing process in one-week earlier compared to control. ConclusionCytotoxicity of SSD in fabricated nanofibrous mat is a critical challenge in designing an effective wound dressing that neutralizes cellular toxicity and improves antimicrobial activity. The PCL/SSD nanofibrous membrane with 500- µm thickness and 0.3% (w/v) SSD showed applicable characteristics as a wound dressing and it accelerated wound healing process in vivo.

Biocompatibility Through Cell Attachment and Cell Proliferation Studies of Nylon 6/Chitosan/Ha Electrospun Mats

Novel cefixime loaded chitosan/HA/Nylon 6 electropsun mats were prepared with excellent swelling properties and were tested for cell attachment and cell proliferation. FTIR spectra shows that hydrogen bonding is developed between composite fibers, as pronounced shape change could be seen in amide I and II peaks. SEM analysis displayed completely different morphology (fiber diameters, general appearance, pore-size and shape) of composite fibers as compared to N6 fibers. Composite fibers showed high thermal stability in thermal gravimetric analysis. The ultimate tensile strength of fiber films was around 4.45 MPa. Both composite and Nylon 6 fibers demonstrated sustained drug release up to 24 h. Although the composite and control (Nylon 6) fibers, both, provided compatible favorable environment for the osteoblast cells, the composite fibers provided a better suited environment for the osteoblast cells differentiation and in parallel supporting cellular population also composite fibers exhibited superior swelling properties than the control which in turn complement the healing properties of wound dressings.

Design of Acacia Gum–Carbopol–Cross-Linked-Polyvinylimidazole Hydrogel Wound Dressings for Antibiotic/Anesthetic Drug Delivery

Keeping in view the antimicrobial nature of polyvinylimidazole, the antioxidant property of gum acacia, the mucoadhesive and gel-forming nature of Carbopol, the anesthetic action of lidocaine, and the antimicrobial action of gentamicin, in the present work, an attempt was made to prepare lidocaine and gentamicin loaded gum acacia–Carbopol–polyvinylimidazole based hydrogel wound dressings for better wound healing. These hydrogel dressings were characterized by 13C NMR, FTIR, SEM, cryo-SEM, AFM, XRD, DSC, swelling, and network parameter studies. Some properties of wound dressings were also determined which include the following: hemolysis, hemostatic potential, oxygen permeability, water vapor transmission rate, antioxidant activity, mucoadhesion, protein adsorption, degradation studies, antimicrobial properties (against Pseudomonas aeruginosa bacteria), microbial penetration, mechanical properties (tensile strength, burst strength, resilience, relaxation, folding endurance and gel strength) drug release, a...

Preparation and characterization of silver nanoparticles on silk fibroin/carboxymethylchitosan composite sponge as anti-bacterial wound dressing.

The infection in burn wounds covered by biologic dressings leads to wound deepening and chronic wounds. The introduction of silver nanoparticles (AgNPs) into biologic dressings is a beneficial method to prevent wound infection and simultaneously promote wound healing. In this study, an AgNP-loaded silk fibroin (SF)/carboxymethylchitosan (CMC) composite sponge was fabricated. AgNPs with a mean diameter of 4.9 nm was synthesized in SF solution in situ. While CMC was incorporated and chemically crosslinked, SF was insolubilized by ethanol annealing. SEM imaging determined that the AgNP-loaded SF/CMC sponge was more porous than the pure SF sponge. Anti-bacterial results, measured by disk-diffusion and bacterial suspension assay, showed that the AgNP-loaded SF/CMC sponge demonstrated effective anti-bacterial activity against S. aureus and P. aeruginosa, and that its anti-P. aeruginosa activity was higher than that of AQUACEL®;Ag. The introduction of CMC improved the water absorption capacity, retention ability, and water vapor transmission rate of the sponge, which are all important properties of wound dressings.

Chitosan Based Dressings for Wound Care

Biopolymer researchers have advanced new strategies to improve the properties of wound dressings over the last decade which is becoming one of the most swiftly growing fields in the biomedical and pharmacy. The advantages of these biopolymers (particularly chitosan) is that, they can be easily processed into different forms which needs to be for different biomedical applications. Chitosan is the well-known natural biopolymer which is safe to be use, biocompatible and biodegradable in nature. This review provides an outline of the chitosan properties and its biomedical properties toward applications in anti-inflammatory and wound caring management.

The dependence of efficacy of cell growth on biosynthetic medicinal materials on the microstructure of their surface

The efficacy of the novel class of dressings was studied. The natural and synthetic polymeric components of them are arranged not in layers, but in a unified structure, i.e., form a new composite material. In particular, it was determined whether the interaction of a dressing surface with cells of injured tissue and/or culture grown in vitro depends on the microstructure of the surface. The efficiency of cell growth has been considered from the point of view of stimulation of cell growth. The microstructure of the surface was studied by the method of high-resolution electron microscopy. The results of the study showed that the structure of biosynthetic dressings depends on variations of the composition and ratio of components. The role of the microstructure of the dressing in the efficacy of its function was demonstrated. Factors producing the most significant effect on the regenerating properties of wound dressings were revealed.

Fabrication of New Chitosan-Based Composite Sponge Containing Silver Nanoparticles and Its Antibacterial Properties for Wound Dressing

The purpose of this research was to investigate chitosan-based composite sponge containing silver nanoparticles (Ag NPs) for wound dressing application. The composite sponge was prepared by a freeze-drying technique, and then immersed in AgNO3 solution with different concentration and autoclaved at 15 psi, 121 degrees C for 15 min for the formation of Ag NPs. The composite sponge containing Ag NPs was characterized by UV-vis spectra, XRD and SEM. The characteristic peaks of Ag in the UV-vis spectra and the XRD pattern revealed the formation of Ag-NPs. The SEM image showed that the silver particles homogeneously distributed on the surface of the composite sponge with an average particle diameter of about 60-80 nm. The contents of silver determined by ICP Single-channel scanning spectrometer were 0.032, 0.096 and 0.166 weight percentage, respectively, when the composite sponge was correspondingly treated with AgNO3 at concentrations of 0.1, 0.25 and 0.5 mM. The results of enzymic degradation in vitro indicated that the Ag-NPs could obviously promote the degradation of the composite sponge. The bacteriostatic and bactericidal properties of the new sponge were preliminarily studied in vitro by using S. aureus E. coli and P. aeruginosa as test microorganisms. The test results demonstrated that the new Ag NPs-loaded chitosan-based composite sponge possessed not only bacteriostatic, but also bactericidal activity against these test bacteria.

In Vitro Evaluation of the Antimicrobial Effectiveness and Moisture Binding Properties of Wound Dressings

A variety of silver-coated dressings and some impregnated with other chemicals are now available in the market; however, there have been few studies analyzing their comparative efficacies as antimicrobial agents. Moreover, their properties for retaining an appropriate level of moisture that is critical for effective wound healing have never been reported. Five commercially available silver-containing and chlorhexidine dressings, Urgotul SSD®, Bactigras®, Acticoat®, Askina Calgitrol Ag® and Aquacel Ag®, were tested to determine their comparative antimicrobial effectiveness in vitro against five common wound pathogens, namely methicillin-sensitive and -resistant Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. Mepitel®, a flexible polyamide net coated with soft silicone, was used as a control. The zones of inhibition and both the rapidity and the extent of killing of these pathogens were evaluated. All five antimicrobial dressings investigated exerted some bactericidal activity, particularly against E. coli. The spectrum and rapidity of action ranged widely for the different dressings. Acticoat® had a broad spectrum of action against both Gram-positive and -negative bacteria. Other dressings demonstrated a narrower range of bactericidal activities. Regarding the absorption and release of moisture, Askina Calgitrol Ag® absorbed and released the most moisture from the environment. Aquacel Ag® also exhibited good moisture absorption and moisture release, but to a lower degree. The other tested dressings absorbed or released very little moisture. Askina Calgitrol Ag® and Aquacel Ag® are good alternative dressings for treating wounds with high exudates and pus. An understanding of the characteristics of these dressings will be useful for utilizing them for specific requirements under specified conditions.

Carbon nanotube‐hybridized supramolecular hydrogel based on PEO‐b‐PPO‐b‐PEO/α‐cyclodextrin as a potential biomaterial

AbstractIn virtue of the potential biomedical application of carbon nanotube (CNT), the CNT was hybridized into a supramolecular hydrogel based on the selective inclusion of α‐cyclodextrin (α‐CD) onto poly(ethylene oxide) (PEO) segments of a triblock copolymer, i.e., PEO‐block‐poly(propylene oxide)‐block‐PEO. Different from the previous report, the content of α‐CD, in contrast to that of ethylene oxide unit, was decreased to decrease the network density in hydrogel and hence improve the diffusion of encapsulated substances. As a result, the modulus of the hydrogels climbed slightly after introducing CNT. Furthermore, as the essential properties for wound dressing, the antimicrobial activity, the skin‐adhesion, and water‐retention of such supramolecular hybrid hydrogels were also verified. On the other hand, the supramolecular hybrid hydrogels inherited the shear‐thinning property and are suitable as an injectable biomaterial. The cell viability assay confirmed the equivalent cytotoxicity of the supramolecular hybrid hydrogels to that of the native hydrogels without CNT. Consequently, such CNT‐hybridized supramolecular hydrogel shows a great potential in the biomedical application. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Irradiation of crosslinked, poly(vinyl alcohol) blended hydrogel for wound dressing

In order to obtain a more ideal hydrogel wound dressing, crosslinked hydrogel films blended with polyvinyl alcohol (PVA), polyvinyl pyrrolidone, kappa-carrageenan (KC), and powder silk were prepared by electron beam, and their physiochemical properties were investigated as a combination of function factors. The experimental results showed that the gel fraction of the hydrogel films depended mainly on irradiation dose and the monomer concentration of the polymers, the properties of hydrogel could be greatly extended or improved by blending homopolymers. The rate of gel formation of the hydrogel was raised, and the water evaporation from hydrogel could be retarded after mixing with KC, while the tensile strength of hydrogel films were obviously increased after mixing with silk. Toxicity and healing effect of PVA/PVP/KC/silk blended hydrogel films as wound dressings were evaluated. The irradiated blended hydrogel showed satisfactory properties for wound dressing, the hydrogel did not induceany acute general toxic effects, and it is effective for fast healing of wound.

Electron beam crosslinked PEO and PEO/PVA hydrogels for wound dressing

Abstract In order to prepare polyethylene oxide (PEO) hydrogel for wound dressing, different molecular weight PEO and PEO/poly(vinyl alcohol), PVA blend hydrogels were obtained with electron beam irradiation. Gel formation of PEO in aqueous solution was saturated at 40 kGy and the achieved gel fraction was 60–70%. The PEO hydrogel obtained was very fragile, hence PVA was added at 10–30% to give toughness to the PEO hydrogel. The PEO/PVA hydrogel blend showed satisfactory properties for wound dressing. To evaluate the healing effect of PEO/PVA hydrogel blend for dressing, the hydrogel covered a wound formed on the back of marmots. Healing under the wet environment of the hydrogel dressing had some advantages compared with that of gauze dressing which gives a dry environment: (1) the healing rate is faster, (2) easier to change the dressing, i.e. the hydrogel can be peeled off without any damage to the regenerated surface, and (3) no dressing material remains on the wound.