Diameter of the vial plays a crucial role in the amyloid fibril formation: Role of interface area between hydrophilic-hydrophobic surfaces.

Number of incurable diseases associated with neurodegenerative syndromes like Alzheimer's, and Parkinson's, are owing to protein aggregation which leads to amyloid fibril formation. In vitro, such fibrillation depends on concentration, temperature, pH, ionic strength, organic solvents, agitation, and stirring, which play a crucial role in understanding the mechanism of fibrillation as well as to identify potential inhibitors for fibrillation. Although these parameters were considered, the precise repeatability of amyloid fibrillation kinetics between laboratories remains challenging. Herein, we have demonstrated that another important parameter such as diameter of the vial in which protein undergoes fibrillation play a key role in the amyloid fibrillation. The various biophysical analyses indicated that the lag time, elongation, and the amount of fibril formation was significantly reduced with decreasing the diameter of the reaction vial from 24 to 15mm. Further, the minimum amount of protein required for fibrillation was determined by the diameter of the vial. The observed fibrillation difference in different vials is most likely due to the variation in the interface area between hydrophobic (air) and hydrophilic (water) surfaces as the diameter of the vial changes. The current results have a major role in the design of drug screening assays for amyloid inhibition.