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Reduced bovine serum albumin adsorption by prephosphatation of powdered zirconium oxide

1997; Elsevier BV; Volume: 121; Issue: 1 Linguagem: Inglês

10.1016/s0927-7757(96)03978-7

1873-4359

Bruno Putman, Paul Van der Meeren, Danny Thierens,

Microfluidic and Capillary Electrophoresis Applications

Abstract The adsorption of phosphate anions to ZrO2 and its influence on protein adsorption have been studied. Phosphate adsorption experiments revealed that phosphate anions had a high affinity for zirconia: in appropriate conditions, a monomolecular layer was adsorbed. Using the electrophoretic light scattering technique, it was shown that the isoelectric point of the zirconium oxide was shifted from pH 6.4 down to pH 3.8. From this shift, it was concluded that specific interactions were responsible for the adsorption behaviour. In addition, the adsorption of bovine serum albumin (which was selected as a model protein) to both bare and phosphated zirconia was investigated: prephosphatation reduced the BSA adsorption by over 50%. Comparing the adsorption behaviour at pH 4.15 and 5.35, it was concluded that electrostatic interactions were of minor importance. From contact angle measurements, the different adsorption behaviour was shown to be due to the increased hydrophilicity of the phosphated adsorbent. On the basis of the present results, the observed effect of phosphate ions in ultrafiltration of proteins on ZrO2 ceramic ultrafiltration membranes may be explained.