Immobilization of bovine serum albumin onto spherical polyelectrolyte brushes in aqueous solution

The adsorption of bovine serum albumin (BSA) in spherical poly(acrylic acid) brushes (SPB) was observed by the methods of turbidimetric titration, rheology, dynamic light scattering (DLS), Zeta potential measurement, and UV spectroscopy. Turbidimetric titration and DLS were used to examine the binding boundaries of protein-polyelectrolyte. The critical pH values where adsorption was initiated (pH_c) and aggregation occurred (pHφ) were determined by turbidimetric titration and DLS, respectively. Adsorption of BSA by SPB occurred at range of 4.6 <; pH <; 7.0 as observed by both turbidimetric titration and DLS. High ionic strength can damage the binding between BSA and SPB. Upon decreasing pH value, the viscosity, the elastic modulus G´ and viscous modulus G” of SPB binding of BSA increased significantly. The binding amount of BSA in SPB was determined by UV spectroscopy.