Thermodynamic characterization of amyloid polymorphism by microfluidic transient incomplete separation
Azad Farzadfard, Antonín Kunka, Thomas O. Mason, Jacob Aunstrup Larsen, Rasmus K. Norrild, Elisa Torrescasana Dominguez, Soumik Ray, Alexander K. Buell
Abstract
separation of these species based on their different diffusivity inside a microfluidic capillary. The method is highly sample economical, using much less than a microliter of sample per data point and its only requirement is the presence of aromatic residues (W, Y) because of its label-free nature, which makes it widely applicable. Using this method, we investigate the differences in thermodynamic stability between different fibril polymorphs of α-synuclein and quantify these differences for the first time. Importantly, we show that fibril formation can be under kinetic or thermodynamic control and that a change in solution conditions can both stabilise and destabilise amyloid fibrils. Taken together, our results establish the thermodynamic stability as a well-defined and key parameter that can contribute towards a better understanding of the physiological roles of amyloid fibril polymorphism.