polymer fibers Dotaz Zobrazit nápovědu
V článku věnujeme pozornost novému trendu v přípravě UHMWPE se zvýšenou odolností vůči otěru, obecně uváděnému jako síťování (crosslinking). Takto modifikovaný UHMWPE lze charakterizovat vyšším stupněm příčných vazeb a žádným, resp. minimálním počtem volných radikálů. Síťovaný UHMWPE se získává ve dvou krocích. Nejprve se UHMWPE za určitých, přesně daných podmínek ozáří ionizujícím zářením a následně prochází tepelnou úpravou, kterou se likvidují vzniklé zbytkové radikály. Správným způsobem modifikovaný polymer vykazuje výrazně vyšší odolnost vůči otěru.
In the article, we focus on a new trend in the preparation of UHMWPE, generally called cross-linking, that provides for a greater resistance to abrasion. UHMWPE thus modified features a higher degree of perpendicular fiber structure and none or rather minimal quantity of loose radicals. Cross-linked UHMWPE is produced in two steps. Firstly, UHMWPE is exposed to ionized radiation, under certain strictly controlled conditions and, subsequently, it undergoes thermal processing that liquidates any remaining loose radicals. Polymer properly modified in this manner possesses distinctly higher resistance to wear.
Electrospinning has garnered significant attention in view of its many advantages such as feasibility for various polymers, scalability required for mass production, and ease of processing. Extensive studies have been devoted to the use of electrospinning to fabricate various electrospun nanofibers derived from carbohydrate gum polymers in combination with synthetic polymers and/or additives of inorganic or organic materials with gums. In view of the versatility and the widespread choice of precursors that can be deployed for electrospinning, various gums from both, the plants and microbial-based gum carbohydrates are holistically and/or partially included in the electrospinning solution for the preparation of functional composite nanofibers. Moreover, our strategy encompasses a combination of natural gums with other polymers/inorganic or nanoparticles to ensue distinct properties. This early established milestone in functional carbohydrate gum polymer-based composite nanofibers may be deployed by specialized researchers in the field of nanoscience and technology, and especially for exploiting electrospinning of natural gums composites for diverse applications.
Combining different antimicrobial agents has emerged as a promising strategy to enhance efficacy and address resistance evolution. In this study, we investigated the synergistic antimicrobial effect of a cationic biobased polymer and the antimicrobial peptide (AMP) temporin L, with the goal of developing multifunctional electrospun fibers for potential biomedical applications, particularly in wound dressing. A clickable polymer with pendent alkyne groups was synthesized by using a biobased itaconic acid building block. Subsequently, the polymer was functionalized through click chemistry with thiazolium groups derived from vitamin B1 (PTTIQ), as well as a combination of thiazolium and AMP temporin L, resulting in a conjugate polymer-peptide (PTTIQ-AMP). The individual and combined effects of the cationic PTTIQ, Temporin L, and PTTIQ-AMP were evaluated against Gram-positive and Gram-negative bacteria as well as Candida species. The results demonstrated that most combinations exhibited an indifferent effect, whereas the covalently conjugated PTTIQ-AMP displayed an antagonistic effect, potentially attributed to the aggregation process. Both antimicrobial compounds, PTTIQ and temporin L, were incorporated into poly(lactic acid) electrospun fibers using the supercritical solvent impregnation method. This approach yielded fibers with improved antibacterial performance, as a result of the potent activity exerted by the AMP and the nonleaching nature of the cationic polymer, thereby enhancing long-term effectiveness.
Nanofibers of natural tree polysaccharides based on three gums namely Arabic (GA), karaya (GK) and kondagogu (KG) have been prepared for the first time using electrospinning. Electrospinning solutions were prepared by mixing gum solutions of GA, GK & KG with eco-friendly polymers such as polyvinyl alcohol (PVA) or polyethylene oxide (PEO). The present study focuses on the effect of electrospinning blended solutions of GA, GK or KG with PVA or PEO, additives which influence system parameters and process parameters. This has important effects on the electrospinning process and the resulting fibers whose morphology and physicochemical properties were evaluated. The mass ratios of 70:30 to 90:10 for PVA: GA, PVA: GK and PVA: KG were observed to establish an optimum blend solution ratio in order to fabricate uniform beadless nanofibers with an average diameter of 240±50, 220±40 and 210±30nm, respectively. Various structural and physicochemical properties of the electrospun fibers were investigated. Furthermore, the comparisons of various functionalities of the untreated and plasma treated electrospun fibers were assessed. The methane plasma treated nanofibers were shown to be of extremely specific surface area, improved water contact angle, high surface porosity and roughness and superior hydrophobic properties compared to untreated fibers.
- MeSH
- arabská guma chemie MeSH
- guma karaya chemie MeSH
- nanovlákna chemie ultrastruktura MeSH
- plazmové plyny chemie MeSH
- Publikační typ
- časopisecké články MeSH
The polymeric cytisine-enriched fibers based on poly(3-hydroxybutyrate) were obtained using electrospinning method. The biocompatibility study, advanced thermal analysis and release of cytisine from the poly(3-hydroxybutyrate) fibers were carried out. The nanofibers' morphology was evaluated by scanning electron microscopy. The formation and description of phases during the thermal processes of fibers by the advanced thermal analysis were examined. The new quantitative thermal analysis of polymeric fibers with cytisine phases based on vibrational, solid and liquid heat capacities was presented. The apparent heat capacity of fibers was measured using the standard differential scanning calorimetry. The quantitative analysis allowed for the study of the glass transition and melting/crystallization process. The mobile amorphous fraction, degree of crystallinity and rigid amorphous fraction were determined depending on the thermal history of semicrystalline polymeric fibers. Furthermore, the cytisine dissolution behaviour was studied. It was observed that the kinetic of the release from polymeric nanofiber is delayed than for the marketed product. The immunosafety of the tested polymeric nanofibers with cytisine was confirmed by the Food and Drug Agency Guidance as well as the European Medicines Agency. The polymeric matrix with cytisine seems to be a promising candidate for the prolonged release formulation.
This review summarizes and broadly classifies all of the major sustainable natural carbohydrate bio-macromolecular manifestations in nature - from botanical (cellulose, starch, and pectin), seaweed (alginate, carrageenan, and agar), microbial (bacterial cellulose, dextran, and pullulan), and animal (hyaluronan, heparin, chitin, and chitosan) sources - that have been contrived into electrospun fibers. Furthermore, a relative study of these biomaterials for the fabrication of nanofibers by electrospinning and their characteristics viz. solution behavior, blending nature, as well as rheological and fiber attributes are discussed. The potential multidimensional applications of nanofibers (filtration, antimicrobial, biosensor, gas sensor, energy storage, catalytic, and tissue engineering) originating from these polysaccharides and their major impacts on the properties, functionalities, and uses of these electrospun fibers are compared and critically examined.
- MeSH
- agar chemie MeSH
- algináty chemie MeSH
- biokompatibilní materiály chemie MeSH
- celulosa chemie MeSH
- chitin chemie MeSH
- chitosan chemie MeSH
- dextrany chemie MeSH
- elektrochemické techniky MeSH
- glukany chemie MeSH
- heparin chemie MeSH
- karagenan chemie MeSH
- kyselina hyaluronová chemie MeSH
- lidé MeSH
- nanotechnologie metody MeSH
- nanovlákna chemie ultrastruktura MeSH
- pektiny chemie MeSH
- škrob chemie MeSH
- tkáňové inženýrství metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Polyacrylonitrile (PAN) membranes have been prepared using needleless electrospinning with wire electrode and characterized by a series of methods HRSEM, XRD, air permeability and area weight measurements in dependence of high voltage and electrode distance. HRSEM analysis revealed the tendency to longitudinal rolling of strip-shaped PAN fibers forming hollow fibers. Combination of XRD analysis and molecular modeling explains this phenomenon as the consequence of the specific crystal structure of PAN fibers, where the isotactic PAN chains are arranged in layers forming belt shaped nanofibers with the strong tendency to roll up longitudinally forming hollow fibers. This effect offers the possibility to create hollow nanofibers by electrospinning with the appropriate choice of structure of polymer chains.
Orally dispersible films (ODFs) prepared by an electrospinning are a novel type of pharmaceutical formulation. This dosage form has the potential to be beneficial for small children and the elderly, who can have problems with administration of classical tablets due to the increased risk of choking and difficulty with swallowing. Due to the highly porous nanofiber morphology, the ODFs examined in this study achieve rapid disintegration into drug microparticles when in contact with saliva. The suspension is then easier to swallow. In this study, we focus on the impact of film composition (polymer matrix composition) on the properties of electrospun membranes. In particular, we prepared ODFs composed of a mixture of PEG 100 000 with HPMC E5 and PVP k90 with HPMC E5. We found significant differences in the structure of electrospinned membranes, where samples containing PEG 100 000 and HPMC E5 exhibited much narrower distribution of fibers. Furthermore, nanofibers containing PVP k90 exhibit a faster disintegration rate, while dissolution of the drug was faster in the case of PEG 100 000 containing ODFs. The improvement was caused by both the structure and composition of the membranes.
- MeSH
- dítě MeSH
- lidé MeSH
- polymery * chemie MeSH
- příprava léků MeSH
- rozpustnost MeSH
- senioři MeSH
- systémy cílené aplikace léků * MeSH
- tablety MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
The microbial biofilms are ubiquitous in nature and represent important biological entities that affect various aspects of human life. As such, they attracted considerable attention during last decades, with the factors affecting the biofilm development being among the frequently studied topics. In our work, the biofilm was cultivated on the surface of polypropylene fibers in a nutrient medium inoculated by the suspension of two unsterile soils. The effects of ionic strength and valence of salt on the amount of the produced biofilm and on composition of biofilm microbial communities were investigated. The effect of valence was significant in some OTUs: Arthrobacter/Pseudarthrobacter/Paenarthrobacter and Bacillus with positive response to monovalent salt (KCl) and Streptomyces, Lysinibacillus, Pseudomonas, and Ensifer with positive response to divalent salt (MgSO4). The significant preference for a certain concentration of salts was observed in the case of OTUs Agrobacterium, Bacillus (both 100 mM), and Brevundimonas (30 mM). A new quantification method based on measuring of oxidizable organic carbon in biofilm biomass, based on dichromate oxidation, was used. We compared the results obtained using this method with results of crystal violet destaining and measuring of extracted DNA concentration as proxies of the biofilm biomass. The dichromate oxidation is simple, inexpensive, and fast, and our results show that it may be more sensitive than crystal violet destaining. The highest biomass values tended to associate with high concentrations of the divalent salt. This trend was not observed in treatments where the monovalent salt was added. Our data confirm the importance of inorganic ions for biofilm composition and biomass accumulation.
- MeSH
- Bacteria klasifikace účinky léků genetika izolace a purifikace MeSH
- bakteriologické techniky MeSH
- biofilmy účinky léků růst a vývoj MeSH
- biomasa MeSH
- kultivační média chemie MeSH
- mikrobiota účinky léků MeSH
- minerály analýza farmakologie MeSH
- polypropyleny MeSH
- půdní mikrobiologie MeSH
- soli analýza farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
This study presents an innovative multifunctional system in fabricating new functional wound dressing (FWD) products that could be used for skin regeneration, especially in cases of infected chronic wounds and ulcers. The innovation is based on the extraction, characterization, and application of collagen (CO)/chitosan-glucan complex hollow fibers (CSGC)/aloe vera (AV) as a novel FWS. For the first time, specific hollow fibers were extracted with controlled inner (500-900 nm)/outer (2-3 µm) diameters from mycelium of Schizophyllum commune. Further on, research and evaluation of morphology, hydrolytic stability, and swelling characteristics of CO/CSGC@AV were carried out. The obtained FWS showed high hydrolytic stability with enhanced swelling characteristics compared to native collagen. The hemostatic effect of FWS increased significantly in the presence of CSGC, compared to native CO and displayed excellent biocompatibility which was tested by using normal human dermal fibroblast (NHDF). The FWS showed high antibacterial activity against different types of bacteria (positive/negative grams). From in vivo measurements, the novel FWS increased the percentage of wound closure after one week of treatment. All these results imply that the new CO/CSGC@AV-FWD has the potential for clinical skin regeneration and applying for controlled drug release.
- MeSH
- Aloe * chemie MeSH
- antibakteriální látky chemie izolace a purifikace farmakologie MeSH
- Bacteria účinky léků růst a vývoj MeSH
- chitosan chemie izolace a purifikace farmakologie MeSH
- fibrilární kolageny chemie izolace a purifikace farmakologie MeSH
- glukany chemie izolace a purifikace farmakologie MeSH
- hojení ran účinky léků MeSH
- kultivované buňky MeSH
- kůže účinky léků zranění patologie MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- mycelium * chemie MeSH
- obvazy * MeSH
- potkani Wistar MeSH
- rány a poranění farmakoterapie patologie MeSH
- rostlinné extrakty chemie izolace a purifikace farmakologie MeSH
- Schizophyllum * chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
