Morphology and mechanical stability of amyloid-like peptide fibrils

Patrick Mesquida, Christian K. Riener, Cait E. MacPhee, Rachel A. McKendry

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Synthetic, amyloid-like peptide fibrils have recently attracted interest as a novel, potentially biocompatible material for applications in biotechnology and tissue-engineering. In this paper, we report atomic force microscopy (AFM) studies of the morphology and mechanical stability of fibrils self-assembled in vitro from the short peptide TTR105-115, which serves as a model system for amyloid fibrils. It forms predominantly straight rods of approximately 1 mu m in length and of diameters between 7 nm and 12 nm. We found polymorphism, with some fibrils exhibiting an unstructured morphology and others showing a regular, longitudinal surface pattern of 90 nm periodicity. Contact mode AFM-imaging in air was utilised to perform mechanical tests of individual fibrils on the nanometer scale with a defined, vertical force in the nN-range applied by the AFM-tip. Above 100 nN, all fibrils showed a permanent, mechanical deformation whereas below 40 nN, fibrils remained unaffected. Tapping-mode AFM-imaging in water led to fibril decomposition within 1.5 h whereas tapping-mode imaging in air left fibrils intact. Additional investigations by circular-dichroism spectroscopy showed that dispersed fibrils were structurally stable in aqueous solution between pH 3 and pH 8, and in sodium phosphate buffer of concentration between 50 mM and 1 M.

Original languageEnglish
Pages (from-to)1325-1331
Number of pages7
JournalJournal of Materials Science: Materials in Medicine
Issue number7
Publication statusPublished - Jul 2007



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