Fabrication of supramolecular hyperbranched polyamidoamine-dextran conjugates and their self-assembly in the presence of EGCG

In this paper, a novel double-hydrophilic supramolecular hyperbranched polyamidoamine-dextran (HPAM-Dex) conjugate was synthesized via host-guest interactions of hyperbranched polyamidoamine containing β-cyclodextrin (HPAM-CD) and adamantyl-modified dextran (Dex-Ad). Then, supramolecular polymeric micelles, EGCG-HPAM-Dex, were prepared by directly mixing HPAM-Dex conjugates with hydrophilic (−)-epigallocatechin-3-gallate (EGCG) in aqueous solution. Variable factors on the self-assembly of the EGCG-HPAM-Dex micelles were investigated. Under optimal conditions, the obtained EGCG-HPAM-Dex micelles had an average diameter of 100-200 nm with controllable size and narrow distribution. ¹H NMR, TEM and SEM results indicated that the EGCG-HPAM-Dex micelles were spherical with a core-shell structure. The formation of EGCG-HPAM-Dex micelles is attributed to electrostatic interactions, hydrogen bonding and hydrophobic interactions. The MTT assay reveals that the HPAM-Dex conjugates have lower cytotoxicity than pristine HPAM owing to the introduction of dextran. The stability and the drug loading and release behaviors of the EGCG-HPAM-Dex micelles were also studied.