Biologically derived polysaccharides have long been used as biomaterials for drug delivery systems (DDS) and regenerative medicine. Amphiphilic polymers, which introduce hydrophobic groups into water-soluble polysaccharides, have been found to form nanosized self-assembling gels (nanogels) in dilute aqueous solutions, using the hydrophobic group assembly area as a crosslinking point, and are used as novel carriers for biopharmaceuticals such as proteins and nucleic acids. In addition, various polysaccharide-based microspheres, porous gels, fibers, and sheets of microscale to millimeter scale have been developed by a bottom-up assembly method using nanogels as building blocks. These materials have a novel gel structure with nanogels as cross-linking points as nanomatrices and are used as functional extracellular matrices in regenerative medicine; for example, it has been shown to function as excellent bone regeneration scaffold materials (Fig. 155.1).