Biomaterial-based blood clot formation is one of the biggest drawbacks of blood-contacting devices. To avoid blood clot formation, their surface must be tailored to increase hemocompatibility. Most synthetic polymeric biomaterials are inert and lack bonding sites for chemical agents to bond or tailor to the surface. In this study, polyethylene terephthalate was subjected to direct current air plasma treatment to enhance its surface energy and to bring oxidative functional binding sites. Marine-sourced anticoagulant sulphated polysaccharide fucoidan from Fucus vesiculosus was then immobilized onto the treated polyethylene terephthalate (PET) surface at different pH values to optimize chemical bonding behavior and therefore anticoagulant performance. Surface properties of samples were monitored using the water contact angle; chemical analyses were performed by FTIR and X-ray photoelectron spectroscopy (XPS) and their anticoagulant activity was tested by means of prothrombin time, activated partial thromboplastin time and thrombin time. On each of the fucoidan-immobilized surfaces, anticoagulation activity was performed by extending the thrombin time threshold and their pH 5 counterpart performed the best result compared to others.
Polylactic acid (PLA) is one of the most produced polymeric materials, due to its exceptional chemical and mechanical properties. Some of them, such as biodegradability and biocompatibility, make them attractive for biomedical applications. Conversely, the major drawback of PLA in the biomedical field is their vulnerability to bacterial contamination. This study focuses on the immobilization of saccharides onto the PLA surface by a multistep approach, with the aim of providing antibacterial features and evaluting the synergistic effect of these saccharides. In this approach, after poly (acrylic acid) (PAA) brushes attached non-covalently to the PLA surface via plasma post-irradiation grafting technique, immobilization of glucosamine (GlcN) and chondroitin sulfate (ChS) to the PAA brushes was carried out. To understand the changes in surface properties, such as chemical composition, surface topography and hydrophilicity, the untreated and treated PLA films were analyzed using various characterization techniques (contact angle, scanning electron microscopy, X-ray photoelectron spectroscopy). In vitro cytotoxicity assays were investigated by the methyl tetrazolium test. The antibacterial activity of the PLA samples was tested against Escherichia coli and Staphylococcus aureus bacteria strains. Plasma-treated films immobilized with ChS and GlcN, separately and in combination, demonstrated bactericidal effect against the both bacteria strains and also the results revealed that the combination has no synergistic effect on antibacterial action.
More than half of the hospital-associated infections worldwide are related to the adhesion of bacteria cells to biomedical devices and implants. To prevent these infections, it is crucial to modify biomaterial surfaces to develop the antibacterial property. In this study, chitosan (CS) and chondroitin sulfate (ChS) were chosen as antibacterial coating materials on polylactic acid (PLA) surfaces. Plasma-treated PLA surfaces were coated with CS either direct coating method or the carbodiimide coupling method. As a next step for the combined saccharide coating, CS grafted samples were immersed in ChS solution, which resulted in the polyelectrolyte complex (PEC) formation. Also in this experiment, to test the drug loading and releasing efficiency of the thin film coatings, CS grafted samples were immersed into lomefloxacin-containing ChS solution. The successful modifications were confirmed by elemental composition analysis (XPS), surface topography images (SEM), and hydrophilicity change (contact angle measurements). The carbodiimide coupling resulted in higher CS grafting on the PLA surface. The coatings with the PEC formation between CS-ChS showed improved activity against the bacteria strains than the separate coatings. Moreover, these interactions increased the lomefloxacin amount adhered to the film coatings and extended the drug release profile. Finally, the zone of inhibition test confirmed that the CS-ChS coating showed a contact killing mechanism while drug-loaded films have a dual killing mechanism, which includes contact, and release killing.
Cabbage plant (Brassica oleracea 𝐿. var. capitata) contains compounds such as polyphenols, minerals, and ascorbic acid, as well as some amino acids such as glutamine, which has anti-inflammatory properties. In addition, its nutrient contains the component of vitamin 𝑈 (𝑆-methylmethionine) which is effective in the treatment and prevention of peptic ulcer disease. The aim of this study is to perform microencapsulation of Brassica oleracea L. var. capitata extract for controlled release of vitamin 𝑈 for peptic ulcer treatment. Within this scope, vitamin U and some amino acids (L-methionine, L-glutamine, 𝐿-histidine, 𝐿-lysine, 𝐿-aspartic acid) were extracted from a cabbage by extraction methods and microencapsulated. The gelatin/gum Arabic and gelatin/sodium alginate polymer complexes were used as wall materials. Morphological analysis of the microcapsules showed that the microcapsules had a homogeneous, spherical shell structure. The results of HPLC analysis confirmed that vitamin 𝑈 and amino acid compounds in cabbage extract are also present in the structure of microcapsules. 𝐹𝑇𝐼𝑅 analysis confirmed the interaction between shell materials and microcapsules, and the similarities in the bands of the plant extract and microcapsules indicated microencapsulation of the plant extract successfully. In vitro release testing of the microcapsules was studied in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) for 48 h. The maximum encapsulation efficiency and release were obtained as 86.92% and 93.6% for the gum Arabic-contained microcapsule, respectively.
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