Cucurbit[8]uril-Based Giant Supramolecular Vesicles: Highly Stable, Versatile Carriers for Photoresponsive and Targeted Drug Delivery.

Highly stable giant supramolecular vesicles were constructed by hierarchical self-assembly of cucurbit[8]uril (CB[8])-based supra-amphiphiles for photoresponsive and targeted intracellular drug delivery. These smart vesicles can encapsulate the model drugs with high loading efficiencies and then release them by manipulating photoswitchable CB[8] heteroternary complexation to regulate the formation and dissociation of supra-amphiphiles that cause dramatic morphological changes of the assemblies to achieve remote optically controlled drug delivery. More importantly, the confocal microscopy analysis, cellular uptake experiment, and cell viability assay have shown that the giant vesicles are able to maintain the structural integrity and stability within actual cellular environments and exhibit obvious advantages for intracellular drug delivery such as low toxicity, easy surface modification for tumor-targeting selectivity, and rapid internalization into different human cancer cell lines. A synergistic mechanism that integrates multiple pathways including energy-dependent endocytosis, macropinocytosis, cholesterol-dependent endocytosis, and microtubule-related endocytosis was determined to facilitate the internalization process. Moreover, cytotoxicity experiments and flow cytometric analysis have demonstrated that the doxorubicin hydrochloride-loaded vesicles exhibited a significant therapeutic effect for tumor cells upon UV light irradiation, which makes the photoresponsive system more promising for potential applications in pharmaceutically relevant fields.