Adsorption of bovine serum albumin protein onto amino‐containing thermosensitive core‐shell latexes

Adsorption of bovine serum albumin (BSA) onto positively charged core‐shell latex particles with a polystyrene core and a rich poly(N‐isopropylacrylamide) (NIPAM)) shell layer was investigated as a function of pH, ionic strength and temperature. Adsorption of BSA protein onto such cationic and thermosensitive particles was found negligible below the LCST of poly(NIPAM), whereas it was much higher above it. In addition, the pH and the salinity dependence of the adsorbed amount at the plateau reflected the role of electrostatic interactions. Protein adsorption behaviour was discussed by taking into account the changes in the interfacial properties of polymer particles (structure of the shell, hydrophilic–hydrophobic balance, charge density) versus temperature, suggesting that coulombic forces are mostly operating in this process. A desorption study showed that the BSA release efficiency was dependent upon the incubation time of the preliminary adsorbed step, and the effect of pH and ionic strength confirmed the contribution of electrostatic interactions. Copyright © 2004 Society of Chemical Industry