Cyclodextrin embedded covalently crosslinked networks: synthesis and applications of hydrogels with nano-containers

Recent advancements in the synthesis of hydrogels containing cyclodextrin (CD) units within the gel network have been reviewed. These cyclic polysaccharides augment the properties of hydrogels, an indispensable class of polymeric materials that find applications in various areas of materials and biomedical sciences. CDs are of great interest in biomedical applications due to their versatile characteristics including low toxicity, bioavailability, biodegradability and most importantly their capability of non-covalent functionalization through inclusion complexation with hydrophobic molecules. Strategies for incorporation of CDs into hydrogel networks include chemical or physical methods to yield either chemically or physically crosslinked networks. The current manuscript focuses on hydrogels where CD moieties are covalently incorporated into the hydrogel matrix. Various crosslinking methodologies explored to date are summarized with a brief explanation of intended application of the obtained hydrogels. Overall, the review intends to highlight the evolution of synthetic approaches to fabricate such materials by highlighting the prominent advantages and associated limitations of preferred methods. Unique attributes that the CD motifs impart to these materials were also highlighted to instigate readers to imagine new approaches in both fabrication and application of CD-containing hydrogels.