Interactions of serum proteins and alkaline phosphatase with poly(styrene/α-tert -butoxy-ω-vinylbenzyl-polyglycidol) microspheres with various surface concentrations of polyglycidol

Interactions of human serum albumin, gamma globulins and alkaline phosphatase with surface of hydrophilic microspheres are described. Relation between the composition of particles surface layer and adsorption/covalent immobilization and activity of proteins is elucidated. The set of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microspheres (poly(S/PGly)) was synthesized via emulsion copolymerization of styrene and α-tert-butoxy-ω-vinylbenzyl-polyglycidol (PGL) macromonomer (Mn = 3000, Mw/Mn = 1.08). The way of addition of PGL macromonomer was different in particular subsets of syntheses; however, the total concentration of all compounds added to the polymerization mixture was kept constant. Namely, PGL was continuously injected beginning injection at various stages of styrene conversion or it was added together with styrene at the beginning of the polymerization. The syntheses yielded microspheres with a number average diameter measured by SEM in a range from 300 to 564.7 nm, and dispersities (Dw/Dn) lower than 1.004, depending on the method of addition of PGL to the polymerization mixture. Studies of proteins' adsorption allowed for determination of relation between the surface concentration of adsorbed protein and chemical composition of the particles interfacial layer. Activation of hydroxyl groups in polyglycidol by 1,3,5-trichlorotriazine allowed for the controlled covalent immobilization of proteins onto particles. The accompanying physical adsorption was low. Studies of the activity of alkaline phosphatase covalently bonded to the surface of the poly(S/PGly) particles with the fraction of PGL in the particles' interfacial layer (fPGL = 20.6 mol% revealed that the activity of the covalently immobilized enzyme was 4.6 times higher than activity of the enzyme adsorbed on the surface of the polystyrene microspheres. Copyright © 2014 John Wiley & Sons, Ltd.