The development of stimuli-responsive polymers has become an important research topic in material science. These polymers can respond to external stimuli, such as light, molecules, redox, pH, temperature and so on. They can undergo physical or chemical changes, for example, gel-sol transition and change of volume. Therefore, they can be widely applied in controlled drug release and biosensors. Bile acids are natural biological molecules in the steroid family bearing hydroxyl and carboxyl functional groups, which can be modified easily and they also have amphiphilic and rigid structure and excellent biocompatibility. The incorporation of bile acids can enrich the structures and functions of the stimuli responsive polymers. On one hand, bile acids or modified ones can either act as monomers for polymerization or be modified to functional groups in polymers. Therefore, different structures of polymers, with bile acids as the main chain, side groups, end groups and core of the star polymers, can be achieved. On the other hand, the introduction of bile acids can not only improve the biocompatibility of the materials, but also change the chemical property of polymers, thus broadening their functions in applications as shape memory materials, chiral separation and drug delivery systems. This paper reviews the recent related work, including the molecular design, structural construction and properties of these polymers. The prospect of future development of polymers containing bile acids is also discussed.

Contents
1 Introduction
2 Polymer containing bile acids on the main chain
2.1 Polyesters
2.2 1,2,3-Triazole-containing polymers
2.3 Polymer based on polycondensation of bile acids
3 Polymers with bile acid moieties as side groups
3.1 N-Isopropylacrylamide copolymers
3.2 Polycations
3.3 Norbornene-based polymers
3.4 Comb-like polymers
3.5 Copolymers for host-guest interactions
3.6 Self-assembly of bile acid-containing polymers
3.7 Oligomers
4 Polymers end-capped with bile acids
5 Star polymers with a bile acid core
6 Conclusion and outlook