Advances in intelligent response and nano-enhanced polysaccharide-based hydrogels: Material properties, response types, action mechanisms, applications

Hydrogels have been widely recognized for their favorable biological adhesion, flexible structure design, high water absorption, and water retention. Hydrogels made of cellulose, chitosan, starch, sodium alginate and other natural polysaccharides as raw materials are biocompatible, biodegradable and non-toxic, and are often used in food, medicine and other fields. However, due to the wide distribution of molecular chain length, an uneven cross-linking mode, poor mechanical strength, and strong brittleness, many functional properties of prepared food-grade hydrogels are not currently suitable for commercial application. In addition, some functional components are not released in specific sites, rendering them limited functionally. The antibacterial effect of hydrogel as antibacterial material is poor. Therefore, it is necessary to develop hydrogels with special functions, good mechanical properties, and stimulation response. This review focuses on the latest research on the classification, properties, functional and beneficial effects of polysaccharide-based hydrogels. It presents summaries on the different types of intelligent responses, response mechanisms, and applications of polysaccharide-based hydrogels. Furthermore, it also reviews the properties and applications of nano-enhanced polysaccharide-based hydrogels.