Carboxymethylated hyperbranched polysaccharide: Synthesis, solution properties, and fabrication of hydrogel.

The periphery of hyperbranched polysaccharides has many end groups that can be functioned and used as sites to interact with their surroundings. A water-insoluble hyperbranched β-d-glucan, coded as TM3a, extracted from sclerotia of an edible fungus (Pleurotus tuber-regium), was fractionated and modified chemically to obtain carboxymethylated derivatives (CTM3a). The solution properties of the carboxymethylated polysaccharides were studied systematically in phosphate buffer saline at 37 °C. The results indicated that the carboxymethylated glucans still kept hyperbranched structure after carboxymethylation, and existed as a swollen sphere-like chain conformation. The introduction of carboxymethylated groups permitted the formation of hydrogels through crosslinking CTM3a and silk fibroin with carbodiimide chemistry. The resultant hydrogels with porous and interconnected structure displayed good mechanical and swelling properties. This work provides some valuable and fundamental information of the natural hyperbranched polysaccharide from mushroom for further application in biomedical devices and tissue engineering.