Continuous Isotropic-Nematic Transition in Amyloid Fibril Suspensions Driven by Thermophoresis

Research output: Contribution to journalArticle

Authors

  • Jianguo Zhao
  • Stephan Handschin
  • Xiaobao Cao
  • Andrew J deMello
  • Raffaele Mezzenga

Colleges, School and Institutes

External organisations

  • Institute for Chemical and Bioengineering; Department of Chemistry and Applied Biosciences; ETH Zurich; Vladimir Prelog Weg 1 Zürich 8093 Switzerland
  • Department of Health Science & Technology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 9, Zurich, 8092, Switzerland.
  • Department of Health Science & Technology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 9, Zurich, 8092, Switzerland. raffaele.mezzenga@hest.ethz.ch.

Abstract

The isotropic and nematic (I + N) coexistence for rod-like colloids is a signature of the first-order thermodynamics nature of this phase transition. However, in the case of amyloid fibrils, the biphasic region is too small to be experimentally detected, due to their extremely high aspect ratio. Herein, we study the thermophoretic behaviour of fluorescently labelled β-lactoglobulin amyloid fibrils by inducing a temperature gradient across a microfluidic channel. We discover that fibrils accumulate towards the hot side of the channel at the temperature range studied, thus presenting a negative Soret coefficient. By exploiting this thermophoretic behaviour, we show that it becomes possible to induce a continuous I-N transition with the I and N phases at the extremities of the channel, starting from an initially single N phase, by generating an appropriate concentration gradient along the width of the microchannel. Accordingly, we introduce a new methodology to control liquid crystal phase transitions in anisotropic colloidal suspensions. Because the induced order-order transitions are achieved under stationary conditions, this may have important implications in both applied colloidal science, such as in separation and fractionation of colloids, as well as in fundamental soft condensed matter, by widening the accessibility of target regions in the phase diagrams.

Details

Original languageEnglish
Article number1211
JournalScientific Reports
Volume7
Issue number1
Publication statusPublished - 27 Apr 2017

Keywords

  • Journal Article