| 1. |
- 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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| 2. |
- Ålander, Eva M., et al.
(författare)
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Agglomeration of paracetamol during crystallization in pure and mixed solvents
- 2004
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 43:2, s. 629-637
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Tidskriftsartikel (refereegranskat)abstract
- The agglomeration of paracetamol during crystallization has been investigated. It is shown that the agglomeration behavior depends on the solvent composition. The following solvent systems were used in isothermal desupersaturation experiments: five different acetone-toluene-water mixtures and the pure solvents acetone, 2-propanol, acetic acid, and ethylene glycol. Sieving, image analysis processed by principal component analysis, and agglomerate strength measurements were used to characterize the product particles. Mixtures with a high concentration of acetone were found to produce a highly agglomerated product with strong agglomerates. In contrast, products from crystallization in ethylene glycol, 2-propanol, acetic acid, and acetone-toluene-water mixtures having a high concentration of water contained not only agglomerates but also a significant fraction of single crystals. Furthermore, the agglomerates formed in these solvents were much weaker than those produced in mixtures with a high content of acetone. The results were correlated with the polarity and the viscosity of the solvents.
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