(391a) Selective Adsorption of Various Proteins By Cationic Spherical Polyelectrolyte Brushes

Cationic spherical polyelectrolyte brushes (SPBs) were synthesized by photo-emulsion polymerization, consisting of a polystyrene core with a diameter around 80 nm and a poly(2-aminoethylmethacrylate hydrochloride) (PAEMH) shell with a thickness from 10 to 50 nm densely grafted on the core surface. Adsorptions of three proteins bovine serum albumin (BSA), β-lactoglobulin (BLG), and papain onto SPBs were observed and compared by turbidimetric titration, dynamic light scattering (DLS), zeta potential measurement, and isothermal titration calorimetry (ITC). Adsorption, aggregation, and desorption of proteins by SPB can be tuned by modulating pH value. The pH regions of adsorption for proteins BSA, BLG, and papain onto SPBs are markedly different and tunable by changing ionic strength and stoichiometry between protein and SPB. The adsorption energetic, affinity, and amount of various proteins onto cationic SPBs were determined by ITC. These findings can lay the foundation for SPB applications in protein separation and selective adsorption of proteins with very similar structures.