Dual Stimuli-Responsive Supramolecular Self-Assemblies Based on the Host-Guest Interaction between β-Cyclodextrin and Azobenzene for Cellular Drug Release.

Health has always been a hot topic of concern, whereas cancer is one of the largest security risks to human health. Although the existing drug delivery systems (DDSs) have been extensively reported and commercially applied, there are still some issues that have yet to be well-resolved, including the toxicity, side-effects, and targeted therapy efficiency of drugs. Consequently, it is still necessary to develop a novel, highly efficient, controlled and targeted DDS for cancer therapy. For this, a supramolecular polymer, β-CD-g-PDMAEMA@Azo-PCL, was designed and developed through the host-guest inclusion complexation interactions between a host polymer, β-cyclodextrin-graft-poly(2-(dimethylamino)ethyl methacrylate) (β-CD-g-PDMAEMA), and a guest polymer, azobenzene modified poly(ε-caprolactone) (Azo-PCL), and was characterized by various analysis techniques. The supramolecular assembly was examined in various pH environments and/or under UV-vis irradiation, showing the formation of supramolecular assemblies from regular spherical shapes to irregular aggregates with various hydrodynamic diameters. The 2D NOESY NMR studies showed the formation of inclusion complexation between Azo-PCL and β-CD-g-PDMAEMA and between β-CD and the side groups of PDMAEMA. The supramolecular assemblies could encapsulate doxorubicin to form spherical core-shell drug-carrying micelles with an entrapment efficiency of 66.1%. The effects of external environment stimuli on the in vitro drug release were investigated, showing light- and pH-modulated drug release properties. The cytotoxicity assessment indicated that the blank supramolecular micelles were nontoxic, whereas the drug-loaded micelles exhibited comparable or even superior anticancer activity to the anticancer activity of free DOX and inhibition of cancer cell proliferation. Therefore, the developed supramolecular assemblies can potentially be used as drug-controlled release carriers.