Bridging the Gap between the Nanostructural Organization and Macroscopic Interfacial Rheology of Amyloid Fibrils at Liquid Interfaces

Abstract

The interfacial behavior of proteins and protein aggregates such as fibrils influences the bulk behavior of multiphase systems in foods, pharmaceuticals, and other technological applications. Additionally, it is an important factor in some biological processes such as the accumulation of amyloid fibrils at biological membranes in neurodegenerative diseases. Here, using β-lactoglobulin fibrils as a model system, we cover a large range of characteristic measuring length scales by combining atomic force microscopy, passive probe particle tracking, tensiometry, interfacial shear, and dilatational rheology in order to correlate the intricate structure of fibril-laden interfaces with their macroscopic adsorption kinetics and viscoelasticity. A subtle change in solution pH provokes pronounced changes in interfacial properties such as alignment, entanglement, multilayer formation, and fibril fracture, which can be resolved and linked across the various length scales involved.