Hemicellulosic Polysaccharides Mimics: Synthesis of Tailored Bottlebrush-Like Xyloglucan Oligosaccharide Glycopolymers as Binders of Nanocrystalline Cellulose

• Published in: Biomacromolecules Vol. 18; no. 10; pp. 3410 - 3417
• Main Authors: Chen, Jing, Travelet, Christophe, Borsali, Redouane, Halila, Sami
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 09-10-2017
• Subjects: Biomimetic Materials - chemical synthesis; Cellulose - analogs & derivatives; Chemical Sciences; Glucans - chemistry; Nanoparticles - chemistry; Organic chemistry; Polymers; Xylans - chemistry
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/acs.biomac.7b01056

We report in this contribution that while low molecular weight hemicellulosic building blocks are known not to interact with cellulosic materials, their multivalent presentation on a polymeric scaffold significantly enhanced the binding interactions that are remarkably in the same range as those usually observed for lectin-carbohydrate interactions. We developed a poly­(propargyl methacrylate) scaffold on which we conjugated, by “post-click” reaction, a variety of azide reducing-end functionalized xyloglucan oligosaccharides with controlled enzymatic-mediated rate of degalactosylation. Bottlebrush-like xyloglucan oligosaccharide glycopolymers (poly­(XGO n )) were obtained and their self-assemblies in aqueous solution were investigated using dynamic light scattering (DLS). We demonstrated that increasing the extent of degalactosylation promoted self-association of poly­(XGO n ), which we attribute to the appearance of hydrophobic domains. A sharp thermoresponsiveness, which corresponds to a decrease in aggregate size with increasing temperature, was observed when the extent of degalactosylation was 30% or greater. Importantly, isothermal titration calorimetry (ITC) and polarized/depolarized DLS revealed that poly­(XGO n ) exhibit a significant capacity to interact with nanocrystalline cellulose (NCC) surfaces particularly for the nondegalactosylated form, emphasizing the important role of galactosyl residues in the binding mechanism and in the 3-dimensional structures of glycopolymers.