Effect of Substrate Surface Wettability on the Adsorption of Magnetic Carrier/Protein Nanocomposites

Hydrophobic ZnO seed layer and superhydrophobic ZnO nanowire array were grown on glass substrate, respectively. The adsorption of the magnetic carrier/bovine serum albumin(BSA) nanocomposites could reach a maximum saturation level upon applying an external magnetic field. The magnetic separation efficiencies using the ZnO nanowire array as the separation substrate were proved to be much higher than those using glass or the ZnO seed layer as the separation substrate. And the difference became large with the decrease of the nanocomposite concentrations. It might be attributed to the small solid. liquid contact area of the superhydrophobic substrate and its strong flow shear. The target protein was then further expanded to the other two typical proteins with different properties, i.e., hemoglobin and lysozyme. And the results proved that the effect rule of the substrate surface wettability on protein adsorption was universal. The superhydrophobic sub- strate has a more obvious advantage in improving the magnetic separation efficiency than commercial glass, polypropy-lene and hydrophobic substrate, and exhibited outstanding magnetic separation efficiencies for "hard" proteins. The present work could contribute to a better understanding of the effect of the interfacial property on protein adsorption behavior, and open up a new avenue to fabricate highly efficient protein separation platform.