Jun Ichi Kadokawa
Kagoshima University, Japan
Biography
Abstract
In this presentation, precision synthesis of polysaccharide-based functional polymeric materials by enzymatic approach is reported. The enzymatic approach has been identified as a useful tool to precisely synthesize functional polysaccharides, which have been interestingly much attention as new biomedical and tissue engineering materials. Phosphorylase is one of the enzymes that are practically used as the catalyst for synthesis of polysaccharides with well-defined structure. Phosphorylase-catalyzed enzymatic polymerization is progressed by using a-d-glucose 1-phosphate and maltooligosaccharide as monomer and primer, respectively, to produce amylose. As the polymerization is initiated from the primer, it can be conducted using primers covalently immobilized to other polymeric materials (immobilized primers), giving rise to amylose-grafted polymeric materials. By means of the property of the spontaneously formation of double helix from amyloses, the phosphorylase-catalyzed enzymatic polymerization using the immobilized primers produces network structures composed of the double helix cross-linking points (Figure 1). In most cases, furthermore, the enzymatic polymerization solutions turn into hydrogels (Figure 1). For example, the phosphorylase-catalyzed enzymatic polymerization using maltooligosaccharide-grafted chitin nanofibers produced amylose-grafted chitin nanofiber hydrogels. Moreover, microstructures, which were hierarchically constructed by lyophilization of the hydrogels, were changed from network to orous morphologies depending on the molecular weights of amylose graft chains.