Adsorption and Aggregation Dynamics of Bovine Serum Albumin at the Air-Water Interface

Protein denaturation and aggregation present significant challenges in the development and stability of biological and pharmaceutical products. Due to the presence of amino acids and their amphiphilic nature, proteins exhibit a propensity to interact and aggregate. These molecules experience pronounced conformational changes at fluid-fluid interfaces, leading to aggregate formation that affects their properties and functionality. Interfacial rheology is a valuable technique to probe these intermolecular interactions, providing insights into the strength and temporal evolution of molecular networks. In this study, we investigated the interfacial properties of Bovine Serum Albumin (BSA) at the air-water interface across various concentrations using a rotational rheometer equipped with double-wall ring (DWR) geometry. This setup effectively differentiates interfacial stresses from bulk stresses. Our findings demonstrate that the interfacial viscoelasticity of BSA solutions increases over time, which indicates the development of a molecular network and progressively stronger interactions at the interface. Moreover, a comparative analysis of the time-dependent viscoelasticity of BSA solutions across different concentrations revealed that the elastic modulus rises up to a certain concentration, beyond which it does not exhibit significant change. Additionally, we observed that while viscoelasticity reaches equilibrium over extended periods, at higher concentrations, it decreases after an initial stabilization phase.