Recent Advances in Amyloids Structural Studies and Thin Film Applications

Abstract

Amyloids are protein-based biomaterials composed of fibrils with cross-β cores. Previously only associated with degenerative diseases, such as Parkinson's disease, Alzheimer's disease, and diabetes, amyloids remain active and functional both in vivo and in vitro conditions, enabling a variety of applications in medicine, nanotechnology, and biotechnology. This review aims to review the most advanced methods for amyloid fibril structural studies, with special attention on amyloid thin films. Selected advances of biomedical and biotechnological relevance will be outlined, and perspectives for future studies in the context of ongoing methodological progress will be discussed.

Keywords: amyloid fibrils; amyloid thin film; cryo-electron microscopy; high brilliance X-ray diffraction.

Figure 1

Resolution scale, sample environment, and data collection conditions for different techniques for imaging and structural studies of amyloids.

Figure 2

Protein molecules are first assembled into amyloid fibrils, which are then stacked into thin films. Atomic force micrograph of the lysozyme fibrils is shown here (adapted from Knowles et al. [84]).

Figure 3

Amyloid fibrils obtained in the protein Langmuir–Blodgett multilayers, prepared by the Langmuir–Blodgett technique (A–C), followed by 150 °C thermal annealing (D), resulting in fibrillation (D1) evident on atomic force micrograph of the phycocyanin-annealed thin film (D2).

Figure 4

(A) Spherulitic structures appearing in PGA multilayered LB film after annealing at 150 °C. (B) Density map based on a composite of scanning nanoXRD patterns from a PGA spherulite with 500 nm (hxv) raster step-increments; The spherulitic core (dotted red rectangle) and filamentary arms extending from the core (dotted blue rectangle) are clearly distinguished. The resolution range of a pixel is shown in the inset. (C) Cryo-EM microED fiber texture pattern with annealed phycocyanin LB multilayers.