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- Ferraz, Natalia, et al.
(författare)
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Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification
- 2012
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Ingår i: Journal of the Royal Society Interface. - : The Royal Society. - 1742-5689 .- 1742-5662. ; 9:73, s. 1943-1955
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Tidskriftsartikel (refereegranskat)abstract
- Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility.
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- Hua, Kai, et al.
(författare)
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Translational study between structure and biological response of nanocellulose from wood and green algae
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:6, s. 2892-2903
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Tidskriftsartikel (refereegranskat)abstract
- The influence of nanostructure on the cytocompatibility of cellulose films is analyzed providing insight into how physicochemical properties of surface modified microfibrillated cellulose (MFC) and Cladophora nanocellulose (CC) affect the materials cytocompatibility. CC is modified through TEMPO-mediated oxidation and glycidyltrimethylammonium chloride (EPTMAC) condensation to obtain anionic and cationic nanocellulose samples respectively, while anionic and cationic MFC samples are obtained by carboxymethylation and EPTMAC condensation respectively. Films of unmodified, anionic and cationic MFC and CC are prepared by vacuum filtration and characterized in terms of specific surface area, pore size distribution, degree of crystallinity, surface charge and water content. Human dermal fibroblasts are exposed to culture medium extracts of the films in an indirect contact cytotoxicity test. Moreover, cell adhesion and viability are evaluated in a direct contact assay and the effects of the physicochemical properties on cell behavior are discussed. In the indirect cytotoxicity test no toxic leachables are detected, evidencing that the CC and MFC materials are non-cytotoxic, independently of the chemical treatment that they have been subjected to. The direct contact tests show that carboxymethylated-MFC presents a more cytocompatible profile than unmodified and trimethylammonium-MFC. TEMPO-CC promotes fibroblast adhesion and presents cell viability comparable to the results obtained with the tissue culture material Thermanox. We hypothesize that the distinct aligned nanofiber structure present in the TEMPO-CC films is responsible for the improved cell adhesion. Thus, by controlling the surface properties of cellulose nanofibers, such as chemistry, charge, and orientation, cell adhesion properties can be promoted.
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