Selective adsorption of acidic protein of bovine serum albumin onto sheet-like calcium hydroxyapatite particles produced by microreactor

Abstract The protein adsorption behavior onto sheet-like calcium hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 (Hap) particles produced by microreactor was examined by using typical acidic bovine serum albumin (BSA) and basic lysozyme (LSZ). Since the sheet-like Hap particles were highly growth through b - (or a -) and c -axes, the particles had larger fraction of bc (or ac ) crystal face. The saturated amounts of adsorbed BSA ( n s BSA ) for the sheet-like Hap nanoparticles were increased with increase in the particle size; i.e., n s BSA showed a good linear relationship with the total surface area of bc and ac faces of each particle. This result strongly suggested that the sheet-like Hap particles progressed in b - and c -axes with large fraction of C sites on bc and ac particle faces and exhibit a high selective adsorption of BSA. On the contrary, very few LSZ molecules adsorbed onto sheet-like Hap particles. Hence the present study developed that the amounts of adsorbed protein, especially for BSA, can be controlled optimally by altering the size of sheet-like Hap particles. It was also found that the sheet-like Hap particles can be applied to separate completely BSA molecules from BSA–LSZ mixed solution.