Natural amphiphilic proteins as tri-block Janus particles: Self-sorting into thermo-responsive gels

Physics and Physical Chemistry of Foods, Wageningen University - P.O. Box 17, 6700 AA Wageningen, The Netherlands and Top Institute Food and Nutrition - P.O. Box 557, 6700 AN Wageningen, The Netherlands

^(a) elke.scholten@wur.nl (corresponding author)

Received: 10 June 2014
Accepted: 11 August 2014

Abstract

Design of particles for controlled assembly into complex 3D structure has been extensively investigated. However, their use in the preparation of such 3D structures has received less attention due to low availability. Here, we use a Janus-type particle in the form of a tri-block of natural origin, the protein zein, to create such 3D structures in the form of a thermo-responsive gel. Assembly behaviour of the tri-blocks can be initiated onto spherical hydrophobic surfaces, which leads to stacking of the tri-blocks into a space-spanning network. Rheological behaviour is dependent on the interplay between the hydrophobic interactions between the tri-blocks and the solvent quality, and can be used to alter the temperature at which the network collapses and the gel strength decreases by two orders of magnitude, representing a more fluid-like behaviour.