The Effect of PEG Crystallization on the Morphology of PEG/peptide Block Copolymers Containing Amyloid β-Peptide Fragments

Abstract

Ordered nanostructures are observed in the melt and solid state for a series of three peptide/PEG conjugates containing fragments of amyloid β-peptides. These are conjugated to PEG with equation image = 3 300 g · mol−1 and a melting temperature Tm = 45–50 °C. The morphology at room temperature is examined by AFM and POM. This shows spherulite formation for the weakly fibrillizing KLVFF-PEG sample but fibril formation for FFKLVFF-PEG. The fibrillization tendency of the latter is enhanced by multiple phenylalanine residues. Simultaneous SAXS and WAXS was used to investigate the morphology as a function of temperature. The secondary structure is probed by FTIR.