4-potential characterization of collagen and bovine serum albumin modified silica nanoparticles: a comparative study

摘要

In this study, bovine serum albumin (BSA) and collagen (COLL) were adsorbed independent of one another, onto the surface of silica nanoparticles (SNPs) at pH's where the -potential of the proteins were equal in magnitude, but opposite to the SNP surface to ascertain the differences in surface coverage and conformation in the adsorbed layer. In both systems, increasing the concentra_tion of free protein resulted in an increase in protein surface coverage and values, with values approaching that of native protein at high surface coverage. However, a lower critical charge reversal concentration range was measured for COLL relative to BSA (COLL: 0-25 μg/mL, BSA: 25_90 _g/mL). Additionally, a considerable difference in for adsorbed protein versus free protein was observed. These results when interpreted in terms of the theory of Ottewill and Watanabe indicate a higher Gibbs energy of associa_tion for COLL versus BSA on SNP surfaces, accompanied by perturbation in protein structure.