Sugar-induced self-assembly of curcumin-based polydopamine nanocapsules with high loading capacity for dual drug delivery

Many drug delivery carriers reported in the literature require multistep assembly or often have very low drug loading capacities. Here, we present a simple sugar-based strategy that feeds the increased interest in high-loading nanomedicine. The driving force of the supramolecular nanocapsule formation is the interaction between curcumin (CCM) and the monosaccharide fructose. Drug and sugar are simply mixed in an aqueous solution in an open vessel, followed by coating the nanocapsules with polydopamine (PDA) to maintain structural integrity. We show that nanocapsules can still be obtained when other drugs are added, producing dual-drug nanoparticles with sizes of around 150-200 nm and drug loading contents of around 90% depending on the thickness of the PDA shell. This concept is widely applicable for a broad variety of drugs, as long as the drug has similar polarities to CCM. The key to success is the interaction of CCM and the second drug as shown in computational studies. The drug was able to be released from the nanocapsule at a release rate that could be fine-tuned by adjusting the thickness of the PDA layer.