Inspection into the Interaction of Bovine Serum Albumin with Gold Nanoparticles by Capillary Electrophoresis

A capillary electrophoretic method was developed to study the interaction of gold nanoparticles (GNPs) with bovine serum albumin(BSA), capable of determining the binding constant and binding capacity. For demonstration citric acid-protected GNPs were tried, the measured bonding constant was 28.6 L/mu mol and the saturated binding capacity was 24 BSA molecules per GNP, corresponding to a surface concentration of 4.5 x 10(12) BSA/cm(2). The determination was shown to depend on the incubating pH value and the concentration of run buffer which should be optimized accordingly. It was found that the peaks of the citric acid-protected GNPs were commonly broad, overlaid with irreproducible bars, but could easily be improved by addition of a small amount of BSA. The established method is expected to be extendable to inspecting the interaction of GNPs with other biomolecules.