Unveiling the Forces Behind BSA Aggregation in a Microfluidic Chip

Abstract Microfluidic chips are powerful tools for investigating protein aggregation. They can be used to study the effects of various variables on protein aggregation, including chemical and physical properties. This study investigated the aggregation of bovine serum albumin (BSA) in two different systems: a bulk system (vial) and a microfluidic chip in which BSA aggregation was induced successfully. Since BSA aggregation in bulk has been thoroughly investigated elsewhere, this study focused on elucidating the forces that drive BSA aggregation in a microfluidic chip designed explicitly for this purpose. This investigation employed a combination of experimental approaches, including biophysical and microscopic methods, and computational simulations using MATLAB and COMSOL Multiphysics. Obtained results revealed that heating provided the necessary energy for BSA's partial thermal unfolding from the onset. In the following, Brownian movement, space restriction, and a high molecular density within the microchannel cross-section contributed to forming clusters akin to the native BSA in the first few seconds. Subsequently, due to the further Brownian movement, intermolecular interactions, and hydrodynamic forces (including shear force), these clusters formed larger aggregates that deposited on the channel sidewalls and underwent a structural conversion, forming amyloid-like fibrillary aggregates within a few seconds.