The recent progress in the preparation of chitosan 6-OH immobilized cyclodextrin and its application

Chitosan is an ideal biomaterial due to its excellent comprehensive properties. Cyclodextrins bearing the cavity structure and amphiphilic properties have become the focus of supramolecular chemistry. The chemical immobilization of cyclodextrin on the chitosan skeleton can be a feasible means to generate supramolecular host material. However, cyclodextrin is usually immobilized on the 2-NH₂ group of chitosan, which suppresses the activities of the amino group such as physiological activities, functionalization, modification, and so on. Therefore, efforts have been made to immobilize cyclodextrin at the 6-OH position of chitosan to maintain the functions of the 2-NH₂ group, and thus to achieve materials with the excellent supramolecular inclusion properties of cyclodextrin and the remarkable advantages of chitosan in membrane formation, immobilization, functionalization and biochemical properties, especially the prominent bioactivity derived from its 2-NH₂. In the present paper, various recently reported synthesis routes for chitosan 6-OH immobilized cyclodextrin derivatives (CTS-6-CD) were introduced in detail. The applications of CTS-6-CD in drug delivery, absorbents, the corrosion inhibition of metal and biosensor due to the unique properties of CTS-6-CD was reviewed. The perspectives on the developing of particular derivatives were also discussed.