Hydrophobization of bovine serum albumin with cationic surfactants with different hydrophobic chain length.

The interaction between bovine serum albumin (BSA) and cationic surfactants with different chain length was investigated. The hydrodynamic diameters, electrokinetic potentials, as well as the fluorescence emission properties of the protein-surfactant complexes with different hydrophobic character were studied. Dynamic light scattering was applied to determine how the size and electrokinetic potential of the protein aggregates changes due to surfactant loading. It was found that by increasing the chain length of the surfactant the required amount of the surfactant for total aggregation of the system is decreased dramatically, which means that in the course on the aggregation process hydrophobic effects should be considered and it was further proved with fluorescence emission intensity measurements. By changing the pH of the protein solution the contribution of the electrostatic interactions to the aggregation processes was studied. It was showed that both hydrophobic and electrostatic interactions are present in the protein-cationic surfactant interaction.