Top-Down Grafting of Xyloglucan to Gold Monitored by QCM-D and AFM: Enzymatic Activity and Interactions with Cellulose
2008 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, no 3, 942-948 p.Article in journal (Refereed) Published
This study focuses on the manufacture and characterisation of model surfaces consisting of end grafted xyloglucan (XG), a naturally occurring polysaccharide, onto a gold substrate. The now well-established XET-technology was utilised for enzymatic incorporation of a thiol moiety at one end of the xyloglucan backbone. This functionalised macromolecule was subsequently top-down grafted to gold, forming a thiol-bonded xyloglucan brush-like layer. The grafting was monitored in-situ with QCM-D and a significant difference in the adsorbed/grafted amount between unmodified xyloglucan and the thiol-functionalised polymer was observed. The grafted surface was demonstrated to be accessible to enzyme digestion using the plant endo-xyloglucanase TmNXG1. The nanotribological properties towards cellulose of the untreated crystal, brush modified surface and enzyme exposed surfaces were compared with a view to understanding the role of xyloglucan in friction reduction. Friction coefficients obtained by the AFM colloidal probe technique using a cellulose functionalised probe on the xyloglucan brush showed an increase of a factor of two after the enzyme digestion and this result is interpreted in terms of surface roughness. Finally, the brush is shown to exhibit binding to cellulose despite its highly oriented nature.
Place, publisher, year, edition, pages
USA: American Chemical Society , 2008. Vol. 9, no 3, 942-948 p.
AFM, QCM-D, xyloglucan, enzymatic, graft, thiol, nanotribology, surface force, friction, colloidal probe, self assembly, model polysaccharide surface, brush layer, polysaccharide interactions
IdentifiersURN: urn:nbn:se:kth:diva-10999DOI: 10.1021/bm701214eISI: 000253926400026ScopusID: 2-s2.0-41949124066OAI: oai:DiVA.org:kth-10999DiVA: diva2:233864
QC 201008042009-09-022009-09-022010-11-15Bibliographically approved