pH-responsive Micelles from a Blend of PEG-b-PLA and PLA-b-PDPA Block Copolymers: Core Protection Against Enzymatic Degradation

Xu, YL (Xu, Yan-Ling)^[ 1,2 ] ; Qu, AT (Qu, Ao-Ting)^[ 1 ] ; Ma, RJ (Ma, Ru-Jiang)^[ 1 ] ; Li, A (Li, Ang)^[ 1 ] ; Zhang, ZK (Zhang, Zhen-Kun)^[ 1 ] ; Shang, ZQ (Shang, Zhi-Qiang)^[ 2 ] ; Zhang, YF (Zhang, Yao-Fang)^[ 1,2 ] ; Bu, LX (Bu, Lu-Xia)^[ 2 ] ; An, YL (An, Ying-Li)^[ 1 ]

CHINESE JOURNAL OF POLYMER SCIENCE, 2018, 36(11): 1262-1268

DOI: 10.1007/s10118-018-2149-0

 WOS:000445208000006

Abstract

pH-responsive micelles with a biodegradable PLA core and a mixed PEG/PDPA shell were prepared by self-assembly of poly(ethylene glycol)-b-poly(lactic acid) (PEG-b-PLA) and poly(2-(diisopropylamino)ethyl methacrylate)-b-poly(lactic acid) (PDPA-b-PLA). The micellization status with different pH and the enzyme degradation behavior were characterized by H-1-NMR spectroscopy, dynamic light scattering measurement and zeta potential test. The pH turning point of PDPA block was determined to be in the range of 5.5-7.0. While the pH was above 7.0, the PDPA block collapsed onto the PLA core and could protect the PLA core from invasion of enzyme, as a result, the micelle exhibited a resistance to the enzymatic degradation.