Preparation and Drug Release Properties of pH/Redox-Responsive Hyperbranched Nano Micelles

Hyperbranched nano micelles with a multi-core-shell structure were prepared via the nucleophilic ring-opening reaction of poly(ethylene glycol) diglycidyl ether (PEGDGE) and cystamine (Cys) in aqueous solution.The drug methotrexate (MTX) was loaded into nano micelles through hydrophobic interactions between MTX and nano micelles to form drug-loaded micelles.The chemical structure and morphology of the micelles were characterized by FT-IR,¹H-NMR,DLS and SEM.The cytotoxicity of nano and MTX-loaded micelles were studied by Methyl Thiazolyl Tetrazolium(MTT) assays.Results showed that the hyperbranched nano micelles had spheric morphology with an average diameter of 100 nm and narrow dispersity.MTX-loaded micelles had drug loading content of 10.32%.The release of MTX was stimuli-responsive under an acidic and reductive condition which simulated the intracellular environment of tumors.MTT assays demonstrated that nano micelles were highly biocompatible in vivo,while MTX-loaded micelles caused pronounced cytotoxic effects to Hela tumor cells.