Cyclodextrin Nanosponges: Present and Perspective

The facile synthesis and the broad applications range of cyclodextrin nanosponges (CDNS) are the pivotal features of these nanoporous, cross-linked polymers. In particular, the use of different cross-linking agents and of reaction conditions allows the obtainment of different families of polymers with tailored properties of swelling, polarity, absorption, adsorption etc. In this communication we point out two state-of-the-art aspects of CDNS: 1.The possible use of CDNS as nano-reactor for stereoselective reactions. Indeed, the the cyclodextrin units provide the chiral pool for asymmetric induction or for stereoselectivity. Examples taken from photocyclodimerization or photo-induced isomerization reactions are reported and discussed. 2.CDNS hydrogels as model systems for the study of water molecules confined into nano- to microscopic cavities. The achievements in this field are in turn beneficial for the design of systems for drug delivery, tissue engineering and regenerative medicine. Some preliminary results on the phase transitions of CDNS hydrogels will be presented. In all cases, the multidisciplinary approach to the characterization of CDNS will be emphasized, with paradigmatic examples taken from different physical methods: NMR, vibrational spectroscopies, optical methods, neutron scattering.