Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution

Biomacromolecules. 2018 Jan 8;19(1):167-177. doi: 10.1021/acs.biomac.7b01420. Epub 2017 Dec 19.

Abstract

We investigate the self-assembly of two telechelic star polymer-peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyrosine. 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 electron microscopy. In contrast to previous studies on linear telechelic PEO-oligotyrosine conjugates that show self-assembly into β-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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Chromatography, Gel
  • Circular Dichroism
  • Humans
  • Hydrogels / chemistry
  • Magnetic Resonance Spectroscopy
  • Microscopy, Electron, Transmission
  • Peptides / chemistry
  • Polyethylene Glycols / chemistry*
  • Polymerization
  • Scattering, Small Angle
  • Solutions
  • Spectroscopy, Fourier Transform Infrared
  • Tyrosine / chemistry*
  • Water / chemistry*
  • X-Ray Diffraction

Substances

  • Hydrogels
  • Peptides
  • Solutions
  • Water
  • Polyethylene Glycols
  • Tyrosine