Physicochemical perspective of cyclodextrin nano and microaggregates

'Chemistry beyond the molecule' is the nickname for supramolecular chemistry. This branch of study is based on molecular recognition that is host-guest chemistry. A number of potential hosts have been defined and applied in scores of studies. Among all potential hosts, cyclodextrins occupy a high position due to their characteristic solubilisation capability and biocompatibility. In the present article we are revisiting the host-guest aspects of cyclodextrins from a physicochemical perspective. We present details of formation and applications of cyclodextrin nanoaggregates induced by guest molecules, the concerned thermodynamics behind the process and also the effect of concentration of the guest molecules on the morphology of the aggregates. This article reviews the topic mainly from the spectroscopic point of view.