화학공학소재연구정보센터
Biomacromolecules, Vol.19, No.1, 167-177, 2018
Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution
We investigate the self-assembly of two telechelic star polymer peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyr-osine. The conjugates were prepared via N-carboxy anhydride mediated ring-opening polymerization from PEO star polymer macroinitiators. Self-assembly occurs above a critical aggregation concentration determined via fluorescence probe assays. Peptide conformation was examined using circular dichroism spectroscopy. The structure of self-assembled aggregates was probed using small-angle X-ray scattering and cryogenic transmission electronmicroscopy. In contrast to previous studies on linear telechelic PEO oligotyrosine conjugates that show self-assembly into beta-sheet fibrils, the star architecture suppresses fibril formation and micelles are generally observed instead, a small population of fibrils only being observed upon pH adjustment. Hydrogelation is also suppressed by the polymer star architecture. These peptide-functionalized star polymer solutions are cytocompatible at sufficiently low concentration. These systems present tyrosine at high density and may be useful in the development of future enzyme or pH-responsive biomaterials.