Добірка наукової літератури з теми "Lyophilized wound dressings"

A rise in the incidence of skin burns and chronic wounds present a first health care problem. Hence collagen – chitosan-based wound dressing has been seen as a way to heal wounds without leaving a scar. Collagen is the most ubiquitous protein found in marine organisms. Here, chitosan plays a vital role in improving the stability of the collagen. The Collagen-chitosan films comprised of collagen derived from skins of Catla catla which were pretreated and lyophilized and confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Thus, in this new approach collagen has been hybridized with the naturally occurring bioactive material chitosan to improve the mechanical properties with enhanced stability, and it can be effectively utilized for the wound dressing in clinical application. Physico-chemical properties and surface morphology of the films were analyzed through SEM and FTIR. Mechanical stability of collagen – chitosan film showed increased tensile strength and elongation at break. The Anti-bacterial and Anti-inflammatory activity of collagen - chitosan films were performed. Also, the in vitro biocompatibility of collagen chitosan films was confirmed by wound scratch assay on fibroblast cells. It was concluded that this present study reveals that the preparation of collagen-chitosan films from a new source of natural collagen could be suitable for the application of wound dressings.

Background. Wound healing as soon as possible is an ultimate goal of treating patients with burns. European guidelines of recent years state that a humid environment is optimal for the treatment of burns. Objective. To describe the modern approach to the treatment of burns. Materials and methods. Analysis of literature sources on this topic. Results and discussion. Over the last 15 years, there has been a significant breakthrough in the armamentarium of wound dressings (WD). The main advantages of modern WD include simplification of the dressing procedure, control of infection, removal of secretions from the wound, creating a favorable environment for healing, and accelerating the cleansing or healing of wounds. Such WD include skin substitutes and interactive dressings. Skin substitutes are divided into synthetic, biological and combined, as well as in temporary and permanent. Dressings, in turn, can be super-absorbent, spongy, hydrocolloid, gel, atraumatic mesh, semi-permeable, etc. After treating wounds with an aqueous antiseptic, such as Dekasan (“Yuria-Pharm”), the exfoliated epidermis is removed and an atraumatic dressing is applied. Sometimes a single application is sufficient for epithelialization of superficial wounds. Dermal burns affecting the epidermis and dermis are burns with incomplete injury depth and can heal on their own. After dermabrasion, the lyophilized xenoskin is soaked in saline with the addition of Dekasan and instantly fixed to the wound surface. Subsequently, the wound is healed by primary tension. Dermabrasion of the wound can be performed mechanically (dry napkin, wet napkin with Dekasan, brush or metal sponge) or surgically (scalpel, dermatome, Water Jet device). Nowadays, it is believed that the creation of a moist environment above the surface of the burn allows epithelial cells to spread horizontally on a thin layer of wound exudate, accelerating wound healing. Hydrogel dressings and shape-resistant hydrogel coatings are widely used in the treatment of limited superficial and border burns. In the exudation phase, a wound coating with nanosilicon is used, which actively absorbs the wound exudate. There are also hydrogel face masks, which have a prolonged effect, cool the damaged area in 60 seconds, eliminate pain, prevent blisters, reduce the likelihood of infection and the spread of burns deep into the tissues. The process of tissue repair and wound healing consists of three phases, which are interrelated and may coincide in time: the inflammatory phase, the proliferation phase and the remodeling phase. Wound healing is affected by the pH of the environment, as many processes, namely, activity of matrix metalloproteinases and their tissue inhibitors, activity of fibroblasts, microbial proliferation, depend on this factor. Interactive WD change the pH of the wound. Conclusions. 1. WD, which support wounds in a humid environment, are an effective means of regulating the wound process. 2. Low pH of wounds changes the qualitative and quantitative composition of the microflora, reduces the microbial contamination of wounds in 100 times. 3. Keeping wounds under modern WD does not increase the level of endogenous intoxication, but on the contrary, improves the course of burn disease. 4. Humid environment promotes the penetration of neutrophilic granulocytes with high enzymatic activity.

Fire and burns represent the fourth cause of death in the world. Numerous options for dressings exist, but their selection should be based on several factors such as burn severity, wound location and water retention. Collagen (COLL) is the most common protein in the human body and, due to its biocompatibility, is the main component in biomaterials development. Mefenamic acid (MA) is a non-steroidal anti-inflammatory drug with analgesic properties, and carboxymethylcellulose (NaCMC) is a biocompatible and biodegradable polymer that is commonly used in biomedical field. Collagen - carboxymethylcellulose - mefenamic acid hydrogels, developed in order to be used in burn treatments were lyophilized and the corresponding spongious matrices were investigated by optical microscopy, FT-IR spectroscopy, water absorption, enzymatic degradation and drug release kinetics studies. All tests revealed proper morphological structure, favourable release patterns, convenient swelling capacity and degradation profiles, indicating the possibility of their use for medical applications.

Gleditsia triacanthos is an aggressive invasive species in Eastern Europe, producing a significant number of pods that could represent an inexhaustible resource of raw material for various applications. The aim of this study was to extract cellulose from the Gleditsia triacanthos pods, characterize it by spectrophotometric and UHPLC–DAD-ESI/MS analysis, and use it to fabricate a wound dressing that is multi-functionalized with phenolic compounds extracted from the leaves of the same species. The obtained cellulose microfibers (CM) were functionalized, lyophilized, and characterized by ATR-FTIR and SEM. The water absorption and retention capacity as well as the controlled release of phenolic compounds with antioxidant properties evaluated in temporal dynamics were also determined. The antimicrobial activity against reference and clinical multi-drug-resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae, Candida albicans, and Candida parapsilosis strains occurred immediately after the contact with the tested materials and was maintained for 24 h for all tested microbial strains. In conclusion, the multi-functionalized cellulose microfibers (MFCM) obtained from the reproductive organs of an invasive species can represent a promising alternative for the development of functional wound dressings with antioxidant and antimicrobial activity, as well as being a scalable example for designing cost-effective, circular bio-economy approaches to combat the accelerated spread of invasive species.

Our study presents a novel collagen wound dressing prepared from freshwater fish skin ( Cyprinus Carpio) collagen type I. Half of the sponges were cross-linked with carbodiimide. The cross-linked and non-cross-linked collagen sponges were subsequently impregnated with gentamicin and lyophilized thus allowing for the attainment of the appropriate gentamicin content without the removal thereof during the cross-linking stage. The structure was evaluated via micro-CT and infrared spectrometry and the structural stability and gentamicin release properties were evaluated in phosphate buffer solution. The sponges were further tested via a rat model of an infected wound with Pseudomonas aeruginosa inoculation and compared with a reference commercial product. The sponges thus prepared provided a degree of open porosity that was comparable to or higher than that of the reference commercial product. Spectrometry analysis revealed that the cross-linked collagen sponge and reference commercial product sponge preserved their secondary collagen structure after 168 h while early accelerated degradation was observed with respect to the non-cross-linked collagen sponge. Gentamicin was released rapidly from all the sponges. Compared to those animals with gentamicin-containing sponges or gentamicin administered intramuscularly, the animals with the cross-linked collagen sponge without gentamicin exhibited marked clinical and laboratory infection signs. Both the administration routes (intramuscular and via gentamicin-containing sponges) provided similar gentamicin plasma levels. The resulting highly homogeneous product which was characterized by excellent structural and clinical properties proved effective in terms of the treatment of a surgical wound infection in a rat model. We demonstrated that all the gentamicin was released from the sponge and was absorbed in the systemic circulation. This is the first time that Cyprinus Carpio collagen has been used in the preparation of wound dressings. Thus, gentamicin-containing sponges provide a promising tool for the treatment and prevention of surgical site infections.

Background A tissue-engineered skin substitute, based on gelatin (“G”), collagen (“C”), and poly(ε-caprolactone) (PCL; “P”), was developed. Method G/C/P biocomposites were fabricated by impregnation of lyophilized gelatin/collagen (GC) mats with PCL solutions, followed by solvent evaporation. Two different GC:PCL ratios (1:8 and 1:20) were used. Results Differential scanning calorimetry revealed that all G/C/P biocomposites had characteristic melting point of PCL at around 60 °C. Scanning electron microscopy showed that all biocomposites had similar fibrous structures. Good cytocompatibility was present in all G/C/P biocomposites when incubated with primary human epidermal keratinocytes (PHEK), human dermal fibroblasts (PHDF) and human adipose-derived stem cells (ASCs) in vitro. All G/C/P biocomposites exhibited similar cell growth and mechanical characteristics in comparison with C/P biocomposites. G/C/P biocomposites with a lower collagen content showed better cell proliferation than those with a higher collagen content in vitro. Due to reasonable mechanical strength and biocompatibility in vitro, G/C/P with a lower content of collagen and a higher content of PCL (GCLPH) was selected for animal wound healing studies. According to our data, a significant promotion in wound healing and skin regeneration could be observed in GCLPH seeded with adipose-derived stem cells by Gomori’s trichrome staining. Conclusion This study may provide an effective and low-cost wound dressings to assist skin regeneration for clinical use.

This diploma thesis is focused on the study of bioactive wound dressings. During the thesis, hydrogel, lyophilized and nanofiber wound dressings were prepared. Hydrogel and lyophilized wound dressings were prepared on basis of two polysaccharides – alginate and chitosan. Nanofiber wound dressings were prepared by spinning polyhydroxybutyrate. All prepared wound dressings were enriched with bioactive substances, which represented analgesics (ibuprofen), antibiotics (ampicillin) and enzymes (collagenase). Into hydrogel and lyophilized wound dressings were all the mentioned active substances incorporated, whereas nanofiber wound dressings were only with ibuprofen and ampicillin prepared. The theoretical part deals with the anatomy and function of human skin. There was explained the process of wound healing and also there were introduced available modern wound dressings. The next chapter of the theoretical part deals with materials for preparing wound dressings (alginate, chitosan, polyhydroxybutyrate) and with active substances, which were used during the experimental part of this thesis. In the theoretical part, the methods of preparation of nanofiber wound dressings and also the methods of cytotoxicity testing used in this work were presented. The first part of the experimental part of this thesis was focused on preparing already mentioned wound dressings. Then, their morphological changes over time and also the gradual release of incorporated active substances into the model environment were monitored. The gradual release of ampicillin was monitored not only spectrophotometrically, but also by ultra-high-performance chromatography. In wound dressings, in which collagenase was incorporated, was also the final proteolytic activity of this enzyme monitored. The effect of the active substances was observed on three selected microorganisms: Escherichia coli, Staphylococcus epidermidis and Candida glabrata. The cytotoxic effect of the active substances on the human keratinocyte cell line was monitored by MTT test and LDH test. A test for monitoring the rate of wound healing – a scratch test – was also performed.