Synthesis, self-assembly, and pH-responsive drug release of PHMEMA-PEG-PHMEMA ABA triblock copolymers

Abstract

A series of tertiary amine containing PHMEMA-PEG-PHMEMA ABA triblock copolymers were synthesized by atom transfer radical polymerization (ATRP) using bromine-capped poly(ethylene glycol) (Br-PEG-Br) and 2-(hexamethyleneimino)ethyl methacrylate (HMEMA) as macro-initiator and monomers, respectively. The chemical structures and molecular weights of triblock copolymers were characterized by ¹H NMR and gel permeation chromatography (GPC). The self-assembly behaviors of copolymers in different pH conditions were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Triblock copolymers self-assembled into micelles in water (pH 7.4) and the micelles disassembled at acidic pH (pH 5.0). Anticancer drug doxorubicin (DOX) was used as a drug model and physically encapsulated into polymeric micelles. The drug release of DOX-loaded polymeric micelles was pH-responsive; the drug-loaded micelles that had higher contents of tertiary amine in polymer pendant groups showed faster release speed. In addition, the drug-loaded micelles showed excellent inhibition efficacy against HeLa cells in vitro.

KEYWORDS:

• pH-responsive
• self-assembly
• drug release
• triblock copolymers
• tertiary amine containing polymers

Acknowledgements

This research work was supported by Fundamental Research Funds for the central Universities, Undergraduate Training Programs for Innovation and Entrepreneurship (No. 201510367005), and Bengbu Medical College (No. BYKY1660 and BYKY1703ZD).

Additional information

Funding

This research work was supported by Undergraduate Training Programs for Innovation and Entrepreneurship (No. 201510367005) and Bengbu Medical College (No. BYKY1660).