Metal-Organic-Framework-Templated Polyelectrolyte Nanocapsules for the Encapsulation and Delivery of Small-Molecule-Polymer Conjugates

Herein, we report a strategy for exploiting nanoscale metal-organic frameworks (nano-MOFs) as templates for the layer-by-layer (LbL) assembly of polyelectrolytes. Because small-molecule drugs or imaging agents cannot be efficiently encapsulated by polyelectrolyte nanocapsules, we investigated two promising and biocompatible polymers (comb-shaped polyethylene glycol (PEG) and hyperbranched polyglycerol-based PEG) for the conjugation of model drugs and imaging agents, which were then encapsulated inside the nano-MOF-templated nanocapsules. Furthermore, we also systemically explored the release kinetics of the encapsulated conjugates, and examined how the encapsulation and/or release processes could be controlled by varying the composition and architecture of the polymers. We envision that our nano-MOFs-templated nanocapsules, through combining with small-molecule-polymer conjugates, will represent a new type of delivery system that could open up new opportunities for biomedical applications.