Studying Mechanical and Structural Properties of β-LG and β-CN Fibrils Using Atomic Force Microscopy

Amyloid fibrils from milk proteins have recently been the subject of extensive investigations in biophysics. The purpose of this thesis is to investigate the dynamics of fibrillation and the mechanical properties of β-LG and β-CN fibers using AFM-Quantitative Nanomechanical Mapping (QNM) and AFM-force spectroscopy. β-LG required one day of heating at 80 °C , pH 2 to fibrillate in solution; β-CN required three days. Using the AFM-QNM mode an average elastic modulus of 4.3 GPa was determined for the β-LG fibers and 3.1 GPa for β-casein fibers. A persistence length of 920 nm was determined using end to end distance and contour length data of β-LG fibers; for β-casein, a persistence length of 2200 nm was determined