<正> The adsorption of protein on nanoparticles was studied by using dynamic light scattering tomeasure the hydrodynamic size of both pure protein and nanoparticles adsorbed with differentamounts of protein. The thickness of the adsorbed protein layer increases as proteinconcentration

but decreases as the initial size of nanoparticles. After properly scaling thethickness with the initial diameter

we are able to fit all experimental data with a single mastercurve. Our experimental results suggest that the adsorbed proteins form a monolayer on thenanoparticle surface and the adsorbed protein molecules are attached to the particle surface atmany points through a possible hydrogen-bonding. Our results also indicate that as proteinconcentration increases

the overall shape of the adsorbed protein molecule continuously changesfrom a flat layer on the particle surface to a stretched coil extended into water. During thechange

the hydrodynamic volume of the adsorbed protein increases linearly with proteinconcentration.