Carrier Surface Chemical Composition On Protein Adsorption Behavior

The adsorption behavior of protein, including the rate, amount, orientation, conformation and bio-activity of adsorbed protein, largely depends on the chemical composition of support surface. The interaction between the adsorbed proteins and the support surfaces involves hydrophobic, electrostatic, hydrogen bonding and van der Waals forces. It has become an important method to tailor the chemical groups on the support surface in controlling protein adsorption. In our work, carboxyl-terminated polystyrene (PS) was polymerized by atom transfer redical polymerization (ATRP), and then this carboxyl-terminated PS was modified to synthesized trifluoromethyl-termin -ated PS and hydroxy-terminated PS. End-group functionalized PS were blend with normal PS to obtain the support with carboxyl(-COOH), hydroxyl(-OH) and trifluoromethyl(-CF3) on its surface, respectively. The supports were hydrolysis under the acid solution condition to measure the surface -COOH, -OH and -CF3 group density, respectively. From the the aspects of support surface chemical composition, surface energy, as well as solution parameters, the adsorption behavior of bovine serum albumin(BSA) was studied. Further, the adsorption of enzyme (lipase) with high biological activity was studied. In our work, a method was established to study protein adsorption by quantitatively controlling the surface chemical composition of the support surface. The conclusions are as follows:1. A series supports with different functional groups were obtained, the functional groups density: 7.2×10^-4mmol/m²(-COOH(H, high dentisy)), 5.1×10^-4mmol/m²(-COOH(L, low dentisy)), 5.5×10^-4mmol/m²(-OH(H) ), 4.3×10^-4(-OH(L) ) and 6.5×10^-4mmol/m²(-CF₃).2. The adsorbed BSA on the support surface was monolayer. Equilibrium adsorption capacity: PS>-CF₃>-COOH(L)>-COOH(H)>-OH(L)>-OH(H). The ratio of support surface functional groups and adsorption amount of BSA is: 9.7(-CF₃), 9.5(-COOH(L)), 14.7(PS-COOH(H)), 9.1(-OH(L)), 13.2(-OH(L)). The hydrophobic interaction between BSA and the support played a major role in the adsorption. The introduction of hydrophilic groups on the support surface induced the decrease of surface adsorption capacity.3. The adsorption rate of BSA on the support: -CF₃(1.627)3). The catalytic activity of adsorbed lipase on the hydrophobic supports and were 12.7% (PS) and 20.5% (-CF₃) of free lipase, respectively, while on the hydrophilic support (-OH) it was the highest, 61.7%, -COOH followed with 36.8%.