Preparations of hyperbranched polymer nano micelles and the pH/redox controlled drug release behaviors

•Hyperbranched polymer nano micelles (NMs) were prepared.•Doxorubicin loading rate in the NMs was as high as 15.38 wt%.•NMs showed pH and reduction sensitiveness.•The NMs were biodegradable and biocompatible.•The NMs had potential applications in drug controlled release.

Hyperbranched polymer nano micelles (NMs) were prepared through a nucleophilic ring opening polymerization between cystamine and polyethylene glycol diglycidyl ether, followed by a reaction of amino groups and dimethyl maleic anhydride. The NMs showed spheric morphologies with hydrodynamic diameters of 106-120 nm. Doxorubicin was loaded in the NMs with loading rate as high as 15.38 wt%; The NMs possessed negative zeta potentials in aqueous solutions of pH 7.4 due to the carboxyl ions on the particle surfaces, but the zeta potentials were converted to positive ones due to the hydrolysis of amide bonds at pH 5.0-6.5, leading to the leaving of carboxyl groups and remaining of amino groups. The disulfide bonds in cystamine were designed in the hyperbranched polymer structures of the NMs, and bonds could be broken by a reducing agent l-glutathione (GSH) (10 mM), resulting in a targeted drug release. The smart NMs displayed good biodegradability and biocompatibility, and they could be potentially used in drug controlled release field.

Graphical abstractThe preparation scheme of pH/Redox sensitive hyperbranched polymer nano micelles.Download high-res image (80KB)Download full-size image