Nanopatterning of Vapor-deposited Aminosilane Film using EB Lithography for Ferritin Protein Adsorption

Abstract

High-density ferritin nanopatterning - the protein and core complex - on a silicon substrate was achieved using nanometric patterns of amino-group modification. These patterns were made through a combination of EB lithography and vapor-phase deposition of 3-aminopropyltriethoxysilane (APTES). An appropriate buffer solution, with respect to pH and Debye length, suppressed ferritin adsorption on the SiO₂ underlayer while ferritins were adsorbed with high density on a nanometer-size APTES layer. We obtained 50-nm patterned ferritins by using a solution with a 1000-nm Debye length (pH 7.0); with this solution, the attractive ferritin-APTES interaction seemed to be strong enough to overcome the repulsive ferritin-SiO₂ interaction.