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 M̄n = 3300 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. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA,.