PH responsive self-assembly and drug release behavior of aliphatic liquid crystal block polycarbonate with pendant cholesteryl groups

Abstract

An amphiphilic liquid crystal (LC) block copolymer based on aliphatic polycarbonate with pendant cholesteryl groups was synthesized by the coupling reaction. The structure and LC properties of the obtained block copolymer were characterized using FT-IR, 1H NMR, DSC, POM and XRD. The results showed the copolymer exhibited broken focal conic texture and fan-shaped texture of a smectic A phase during the heating and cooling process. Moreover, this copolymer showed mesophase state below body temperature, and it would be promising candidate as self-assembly material for applications in drug delivery. In addition, the self-assembly, drug loading and release behavior of the LC copolymer were investigated with UV–vis, DLS and SEM. It was found that the initial copolymer concentration and the pH value had a critical influence on the self-assembly behavior and the particle size of the micelles. What's more, the drug release also presented a pH response and the drug-loaded copolymer micelles were stable.