Chain Conformation Transition Induced Host-guest Assembly between Triple Helical Curdlan and β-CD for Drug Delivery
The unique conformation transition from triple helix to single coils for the triple helical β-D-glucans has pave the way to fabricate various functional nanocomposites through the denature-renature process. This study firstly reports a novel kind of naturally-derived supramolecular polymer micelles consisting of the single-stranded chains of Curdlan (CUR) and β-CDs. It is proposed that β-CDs as the host molecules were threaded onto the single β-glucan chains (denatured triplex CUR) via the host-guest interaction, thereby the formation of supramolecular micelles. The results from the 1H NMR, FT-IR, XRD and 2D 1H NOESY NMR confirmed the formation of inclusion complex and the existence of core-shell structure of the supramolecular assembly. TEM images and DLS revealed that the self-organized micelles displayed the regular spherical shape with an average diameter of ~27 nm. Furthermore, the hydrophobic anticancer drug camptothecin (CPT) was selected as a model drug and successfully encapsulated into the CUR/β-CD micelles. The drug-loaded micelles exhibited a steady sustained-release pattern regardless of the environmental pH. The flow cytometry and confocal laser scanning microscopy measurements confirmed that the CPT-loaded micelles could be well internalized into HepG 2 cells and continuously release the drug molecules inside the tumor cells. Furthermore, the in vivo experiments demonstrated that CPT-loaded micelles could effectively inhibit tumor growth by comparison to free drugs. This concept will give a favorable platform to construct intelligent drug delivery systems for potential use.