جستجوی مقالات مرتبط با کلیدواژه « زخم پوش » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Hydrogels are three-dimensional networks of hydrophilic polymers capable of absorbing and retaining significant amounts of fluids, which are also widely applied in wound healing, cartilage tissue engineering, bone tissue engineering, release of proteins, growth factors, and antibiotics. In the past decades, a lot of research has been done to accelerate wound healing. Hydrogel-based scaffolds have been a recurring solution in both cases, although their mechanical stability remains a challenge, some of which have already reached the market. To overcome this limitation, the reinforcement of hydrogels with fibers has been investigated. The structural similarity of hydrogel fiber composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel formation techniques and fiber spinning methods has been very important in the development of scaffold systems with improved mechanical strength and medicinal properties. Hydrogel has the ability to absorb secretions and maintain moisture balance in the wound. In turn, the fibers follow the structure of the extracellular matrix (ECM). The combination of these two structures (fiber and hydrogel ) in a scaffold is expected to facilitate healing by creating a suitable environment by identifying and connecting cells with the moist and breathing space required for healthy tissue formation. Modifying the surface of fibers by physical and chemical methods improves the performance of hydrogel composites containing

The skin, as the first defense barrier against the entry of pathogens into the body, helps to heal the wounds through four stages including homeostasis, inflammation, proliferation, and regeneration. Today, various wound dressings have been introduced to help the body's immune system to improve the speed and quality of wound healing. Conventional wound dressings include polyurethane foams and elastomers, hydrocolloids, hydrogels, semipermeable films, alginate wound dressings, and electrospun polymer nanofibers. Wound dressings based on polymer nanofibers have received a lot of attention for reasons such as similarity to the extracellular matrix (ECM), the desired cell adhesion, high surface-to-volume ratio, gas exchange capability, nutrient supply, and fluid evaporation control. So far, the use of electrospun polyurethanes for the preparation of wound dressings has been reported in various studies. However, the results of studies on a wide range of wound dressings have shown that almost no polymer alone can heal different wounds, effectively. For this reason, many efforts have been made recently to develop polyurethane wound dressings to heal various types of wounds. In this regard, natural polymers have been used due to properties such as biological activity, biocompatibility, and biodegradability along with polyurethanes with desirable physical and mechanical properties. In this article, after introducing the the mechanism of wound healing and describing the characteristics of an ideal wound dressing, the polyurethane/natural polymer blends nanofibers for use as electrospun wound dressings will be discussed.

In-situ forming systems are liquid or viscous injectable materials that after being injected into the body, due to mixing with reactive substances or in response to new conditions (temperature, pH, presence of special molecules or ions, visible or ultraviolet light radiation), they formed a semi-solid material or gel. In the recent years, due to the unique characteristics of in situ forming systems, preparation and investigation of these systems for wound healing have gained increasing attentions. In addition to easy and non-invasive injection of in situ forming systems, these materials can completely fill irregular wound defects and adhere to the wound edge tissues. Also these materials can simultaneously act as a controlled drug delivery system, cell carrier/tissue scaffold, hemostatic agent and tissue-adhesive. Until now, several physical, chemical and enzymatically cross-linking methods have been used to prepare in situ forming systems/hydrogels. In this review, various emerging and innovative approaches being developed and utilized for the preparation of in situ forming systems/hydrogels for wound dressing are reviewed. Also challenges and future prospects of these systems are discussed.

Improvement and development of extraction, purification and modification of keratin proteins which are extracted from hair, wool, feathers, hooves, horns and nails has led to increase in this protein utilization for biomaterial constructions. Having had properties such as biocompatibility, biodegradation,existence of RGD and LDV amino acid sequences ,which are critical elements in cell attachment, and self- assembling to different forms including fibers, films, gels and sponges, keratin has used for many variable medical applications: drug delivery, tissue engineering and wound healing. This article takes keratin’s structure, its extraction methods, keratin- based biomaterials that have been made till today and some of keratin’s medical applications into consideration. Finally at the end of the article we have pointed some of keratin’s merits in comparison with some proteins namely gelatin, cellulose, aliginate, collagen and chitosan, breifly. Based on keratin’s properties, it can be projected that this protein will find its state among biomaterials.

The skin is the largest organ of the body, with a total area of about 20 square feet. ... The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone.The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organ. WOUND IS an injury to living tissue caused by a cut, blow, or other impact, typically one in which the skin is cut or broken. Novel wound dressings have practiced incessant and noteworthy variations as the earliest periods. The expansion begins with the usage of natural-materials to merely covering the wounds to the materials of the existing period that could be particularly manufactured to display numerous unexpected purposes. The modern bandage-materials constructed via bio-polymeric nano-fibers holding several active-compounds that are useful for the healing of wounds. With the correct selections of bio-polymers using for production of these nano-fibrous materials, they could improve the healing of wounds expressively compared with the conventional dressing materials, such as gauze. The novel wound dressings could be completed such that they have bio-active ingredients, for instance anti-microbial, anti-bacterial, and anti-inflammatory agents, which could be released to the wounds improving their healing. This review offers an overview of various kinds of wounds, operational factors in wound healing and different forms of wound dressing materials with a superior highlighting to those manufactured of nanofibers.

Research Subject: 

One of the important methods in the treatment of skin wounds is the use of wound dressings. Recently, the use of polymer-based wound dressings has become increasingly common. The use of natural polymers is very important in wound dressings. The aim of the present study is to design and manufacture a polyvinyl alcohol/aloe vera wound dressing with the capability of healing skin wounds.

Research Approach:

 The electrospinning method was applied to prepare the samples. Aloe vera gel was first extracted, purified, and powdered by freeze-drying. In all samples, the amount of polyvinyl alcohol and aloe vera powder was fixed at 8 wt.%. This value was selected empirically based on the quality of the produced fibers. Different samples including different amounts of polyvinyl alcohol and aloe vera were produced and their properties including morphology, tensile strength, swelling, degradability, and antimicrobial properties were investigated.

The results showed that the dropless random oriented fibers with uniform diameter were produced. The diameter increased with increasing aloe vera contribution, which was attributed to an increase in viscosity due to the presence of aloe vera. With increasing aloe vera contribution in the samples, tensile strength decreased and the elongation percentage increased. The swelling behavior of the specimens was evaluated by measuring the weight of the specimens in a simulated skin environment and the results showed that the presence of aloe vera increased the hydrophilic properties of the specimens. Antimicrobial activity of the samples against two gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was investigated using the disk diffusion method and it was found that the presence of Aloe vera in the samples brought antimicrobial activity against Pseudomonas aeruginosa. Finally, the findings of this study confirm the feasibility of using polyvinyl alcohol /aloe vera for the production of the electrospun wound dressing.

Electrospinning, as a versatile nanofiber fabrication method, has evinced a lot ofattention due to its simplicity, efficiency and ability to produce continuous nanofibers.However, electrospinning of natural polymers such as proteins and polysaccharides seemsto be challenging for different reasons mainly in the absence of appropriate solvent, highviscosity or in some cases polyelectrolyte nature of solutions. Among natural polymers,alginate with its abundant algal source, structural and chemical resemblance to extracellularmatrix and desirable properties like biocompatibility and biodegradability, has attracted theattention of researchers extensively. Alginate has a great potential in many applications indifferent areas in medicine including tissue engineering, drug delivery and wound dressingfabrication. Also a vast number of studies in literature have focused on fabricating alginatenanofibers through electrospinning, no considerable success in achieving nanofibers withhigh alginate content has been reported. Through evaluating different studies and reports inthis regard, it becomes evident that part of the challenge is due to the lack of a comprehensivedescription focused on investigating and analyzing the conducted studies and underlyingstrategies. Hence, the aim of this review is to examine challenges and obstacles in alginateelectrospinning and to open discussions in literature, in order to pave the way for moreintended and successful research in this field.

Wound environment is susceptible to growth of microorganisms and infection. To prevent the infection and accelerate the process of wound healing, antibacterials are sometimes required. The purpose of this study is to develop a bacterial resistant wound dressing based on Henna , a natural bioactive agent. After separating impurity of Henna leaves, they were milled and dissolved in ethanol. In the next step, cotton or polyester fabrics were impregnated with filtered ethanol extract of Henna leaves using exhaustion method. The antimicrobial properties of cotton and polyester fabrics were quantitatively measured by the standard penetration test (AATCC 100-190) against Staphylococcus aureus as gram-positive and E. Coli as gram-negative bacteria. The findings show that the cotton fabric impregnated with Henna extract has an acceptable antibacterial properties against gram-positive bacteria with poor antibacterial effect against gram-negative bacteria. Moreover, the polyester fabric treated with Henna extract did not show any antibacterial properties against both gram negative and gram-positive bacteria. This was attributed to the high temperature which was used for treatment of polyester fabrics with Henna extract.

Wound healing is important in medicine so that the development in this area can affect a major impact on quality of patient life. Using suitable dressing is one of the effective role in wound healing. In recent years, new generation of wound dressing with different formats like sponge, film, hydrocolloid, and so on are developed. However, fewer dressing has complete requirement of wound healing. Recently, electrospun polymeric nanofibers is widely considered due to their unique properties in wound dressing and healing. Electrospinning has been widely used as a nanofiber fabrication technique. Polymeric nanofibers with different morphologies and dimensions can be obtained from electrospinning method. These nanofibers show high surface area to volume ratio, tunable porosity and facile surface functionalization. These characterization lead to different application especially in medicine. This report gives us an overview of some recent advances of electrospinning, fabrication of polymeric nanofibers and their application in wound healing. First, we briefly discuss the wound healing process then the electrospinning process and fabrication of electrospun nanofibers are investigated. Finally, nanofibers in combination with others nanomaterials and their application in wound dressing and antibacterial properties are studied.

Advanced wound dresses are antimicrobial materials that can keep the wound surroundings moist and do not stick to wound. Therefore, in this research, the purpose is to coat a antimicrobial nanoemulsion on a polypropylene(PP) substrate to achieve the mentioned characteristics. non-woven samples of PP were coated with nanoemulsion (2g lipid, 0.3g carboxymethyl cellulose, 10 ml nanosilver) and drug containing nano emulsion (0.25g mupirocin, 0.25g lidocaine and 0.025g betamethasone). The specimens were characterized by infrared spectroscopy (FTIR), scanning electron microscopy to examine morphological structure, projectina microscopy, antimicrobial tests, water absorption and water maintenance teste. Scanning electron microscopy and projector microscopy and FTIR spectroscopy results confirmed the subsidence of nanoemulsion (EL-CS) and drug containing nano emulsion in the PP substrate, both coated samples ( EL-CS and EL-CSグ) completely inhibited growth of both gram-negative (E-Coli) and positive ( S-Areus) bacterias. The results of water absorption and water maintenance experiments showed that EL-CS coated samples had more absorbtion time (30 min) and water storage (60 min) comparing to non wrapped samples, but the EL-CSグ specimen did not show a significant difference in the two above-mentioned factors comparing to EL-CS. the prepared nanoemulsions and wound dresses obtained from them can have acceptable properties from use in medical appliations.

The skin is the largest organ in the body which protects the internal organs against external injury. When the skin is damaged, microorganisms attack easily and cause infection in humans. Many efforts have been made for development of new products to protect the skin from damage and dehydration. Because of the diversity in the wound dressing products, one may possibly be confused when choosing a suitable wound dressing. Although, protection of the wound from infection is one of the reasons for using a wound dressing, acceleration of wound healing process is the main goal. In this paper, we have reviewed several types of modern wound dressings regarding their efficiency in each stage of wound healing. Commercial wound dressings in the form of hydrogels, hydrocolloids, films, foams and nanofibers are introduced and their properties are discussed. Chitosan, alginate and honey are the main common polysaccharides which are usually used as wound dressing materials. The effect of these polysaccharides on wound healing is also described. Finally, the recently developed smart wound dressings which are able to detect the wound infection are presented.

The bed of an open wound is prone to infection because of good conditions for microorganisms to grow in a moist, warm and nutritious environment. Using an antibacterial wound dressing, the healing of the wound can be accelerated. Antibacterial properties of natural dyes have been studied by researchers in recent years. On the other hand, the efficiency of fine fibers in wound dressing has been demonstrated due to increasing its contact area with the skin and simulation of extracellular matrix. In this study, polyvinyl alcohol (PVA) microfibers were fabricated by electrospinning process and heat treatment was used to increase the stability of microfibers against aqueous solutions. It is notable to say that untreated PVA microfibers dissolve in aqueous solutions easily. XRD spectrum was used for structural characterization of PVA microfibers after heat treatment. The results showed an increase in the crystallinity of the microfibers after heat treatment. Antibacterial properties of some natural dyes (green walnut shells, Punicagranatum, Urticadioica) were investigated by dipping PVA microfibers in the natural dyes solutions extracted by different solvents such as water and ethanol. In the end, the antibacterial property of PVA microfibers dipped in Punicagranatum extract solution for both pathogenic strains of gram-positive (Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) was demonstrated. PVA microfibers dipped in aqueous solution of Punicagranatum showed stronger antibacterial property than those dipped in ethanolic Punicagranatum extract solution. The SEM images indicated that morphology of PVA microfibers preserved after dipping in the natural dyes solution extracted by water and ethanol, confirming stability of PVA microfibers after heat treatment.