Enzyme-catalyzed propagation of cello-oligosaccharide chains from bifunctional oligomeric primers for the preparation of block co-oligomers and their crystalline assemblies

Block co-oligomers have gained increasing attention for fine and precise control of self-assembled nanostructures. Recently, we demonstrated that cellodextrin phosphorylase (CDP) catalyzed the propagation of cello-oligosaccharides from monofunctional oligo(ethylene glycol) (OEG) primers, namely, glycosyl acceptors, for the synthesis of diblock co-oligomers and their crystalline assemblies. Therefore, the application of appropriate oligomeric primers to the CDP-catalyzed synthetic system has the potential to further extend the synthesis of unique cellulosic block co-oligomers. In this study, we investigated the CDP-catalyzed propagation of cello-oligosaccharide chains from bifunctional oligomeric primers. Two types of primers (Glc-BiP and Cello-BiP) were synthesized by introducing d-glucose and cellobiose into both ends of OEG with five repeating units via a Huisgen cycloaddition reaction. It was plausible from systematic characterizations that cello-oligosaccharide chains were propagated from one end of Glc-BiP, whereas the chains were propagated from both ends of Cello-BiP. The findings will be significant to gain fundamental knowledge on the CDP-catalyzed synthesis of various cellulosic block co-oligomers and have the potential to produce novel cellulosic nano- to macroscale materials.