Chitosan coordination driven self-assembly for effective delivery of curcumin.

Self-assembly of metal-ligand coordination is of immense scientific interest in supramolecular construction of functional materials duo to their desirable functional properties. Herein, we investigated a designable coordination driven self-assembly to simultaneously enhance the water solubility and biological stability of curcumin (Cur). On the basis of amino group in chitosan (CS), it was chosen as the high-affinity anchors for coordination nanocomplexes, in which Cur were incorporated into the amino group by coordination bonding, forming a CS-metal-Cur architecture. The sizes of these nanocomplexes can be tuned by the feed concentrations of CS as well as the kind of metal ions. Time dependent absorption spectral measurements demonstrated the significant increase in hydrolytic stability of Cur after forming nanoparticles (NPs) especially for the CS-Cu-Cur NPs. Particularly, the formed CS-metal-Cur NPs can be efficiently triggered by pH, which was stable under physiological conditions while releasing encapsulated drugs under low pH conditions in a sustained manner. Based on cellular uptake study and cytotoxicity experiments, CS-metal-Cur NPs were shown to possess highly efficient internalization and an apparent cytotoxic effect. The high drug-loading capacities and responses to pH value, substantially enhanced antitumor activity of Cur provided this nanocomplex with promising properties for biomimetic and biomedical applications.