Electrostatic Placement of Nanodots onto Silicon Substrate Using Ferritin Protein Supramolecules with Control of Electrostatic Interaction in Solution

The behavior of the electrostatic adsorption of a single ferritin protein supramolecule, which formed a nanodot in its inner cavity, on a nanometric 3-aminopropyltriethoxysilane (APTES) pattern made on an oxidized Si substrate was studied using a numerical calculation. The total interaction free energy of the system, which included a ferrin, a substrate with an APTES nanopattern and a buffer solution, was calculated. The obtained distribution of the interaction potential that ferritin experiences can be used to explain theoretically the ferritin adsorption onto a quadrilateral array of 15-nm-diameter APTES nanodisks placed at intervals of 100 nm under a Debye length of 14 nm. This numerical calculation method described here can be applied to the estimation of the electrostatic adsorption behavior of nanometer-sized material as well as proteins.