Nano carriers

due to the enhanced osmotic blockade (EPR) effect

can highly enrich in the tumor site

which is conducive to enhancing the internal circulation time and drug stability

and thus become a powerful means to enhance the therapeutic and diagnostic effect of tumor. As a natural biological macromolecule

polysaccharide has good biocompatibility and biological function

which can achieve active targeting. For example

hyaluronic acid has the function of specific targeting to CD44 receptor. Therefore

the nano carrier prepared from polysaccharide is one of the excellent candidate materials for anticancer drug encapsulation and targeted controlled release. At present

dextran

chitosan

hyaluronic acid

alginate and other polysaccharides have been successfully used in the preparation of polysaccharide nano carriers and related biomedical applications. Among the different methods of preparing polysaccharide nano carriers

including emulsification and self-assembly

self-assembly has become the main way of preparing polysaccharide nano carriers because of its wide application and controllable performance. The self-assembly of polysaccharide nano carriers mainly includes polyelectrolyte adsorption self-assembly

two-step self-assembly based on polysaccharide polymer

and onestep polymerization/self-assembly. At present

the preparation of polysaccharide nano carriers is mainly through two steps: first

the modification of polysaccharide or the synthesis of polysaccharide copolymers

and then the self-assembly of polysaccharide copolymers induced by different driving forces. However

the complex modification methods of polysaccharides and the low solid content in the self-assembly of polysaccharide solution result in the low aging rate of the two-step preparation of polysaccharide nano carriers

which is difficult to meet the needs of practical application. In recent years

some research groups including us have proposed the "one-step "preparation of polysaccharide nano carriers by the" polymerization self-assembly" two in one way. From the point of view of polysaccharides

in the process of grafting copolymerization of monomers on the main chain of polysaccharides

the solution phase self-assembly of the copolymers is driven

and then the nano carrier of polysaccharide group is prepared in one step. In the "one-step" approach

the preparation efficiency of nano carriers can be significantly improved

and the nano carriers can be given specific functionality by introducing appropriate functional monomers. This approach provides a new way for the preparation of polysaccharide nano carriers. In this paper

the self-assembly methods for the preparation of polysaccharide nano carriers are introduced. Based on the induction of the driving force for the preparation of polysaccharide nano carriers by "two-step" method

the " one-step" method for the self-assembly induced by graft copolymerization is emphasized. In addition

based on the special biological functions of polysaccharides

such as cell recognition

this paper also introduces the active target drug transport and other biological applications of polysaccharide nano carriers

in order to provide reference for the efficient preparation of polysaccharide nano carriers with biological functions.