<p>This thesis describes the improvement of two radically different cellulose materials, paper and artificial blood vessels, constructed from two diverse cellulose sources, wood pulp and <em>Acetobacter xylinum</em>. The improvement of both materials was possible due to the natural affinity of the hemicellulose xyloglucan for cellulose.</p><p>Chemical and mechanical pulps were treated with xyloglucan in the wet-end prior to hand sheet formation or by spray application of dry hand sheets, loading a comparable amount of xyloglucan. The tensile strength increases for the wet-end treatment and spray application were 28% and 71% respectively for bleached soft wood, compared to untreated sheets (20.7 Nm/g). The corresponding strength increases for hand sheets made of thermo-mechanical pulp were 6% and 13% respectively compared to untreated sheets (42.4 Nm/g). The tendency for chemical pulp to be superior to mechanical pulp with respect to strength increase was valid even for tear strength and Scott-Bond. These results suggest, in agreement with other studies, that adhesion of xyloglucan to wood fibres is dependent on their degree of surface lignification.</p><p>Also, a method was developed to increase the blood compatibility of artificial blood vessels constructed of bacterial cellulose. Xyloglucan was covalently linked to the endothelial cell adhesion motif (Arg-Gly-Asp). To obtain this, new solid-phase coupling chemistry was developed. Xyloglucan oligosaccharides (XGO) were transformed into XGO-succinamic acid via the corresponding XGO--NH<sub>2 </sub>derivative prior to coupling with the N-terminus of the solid-phase synthesised Gly-Arg-Gly-Asp-Ser peptide. The resin-bound glyco-peptide was then cleaved and enzymatically re-incorporated into high molecular weight xyloglucan. The glyco-peptide was further adsorbed onto bacterial cellulose scaffolds, increasing the adhesion and proliferation of endothelial cells and therefore blood compatibility.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:kth-4437 |
| Date | January 2007 |
| Creators | Ahrenstedt, Lage |
| Publisher | KTH, School of Biotechnology (BIO), Stockholm : Bioteknologi |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Licentiate thesis, comprehensive summary, text |
| Relation | Trita-BIO-Report, 1654-2312 ; 2007:6 |
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