Fabrication of a two-dimensional array of nano-particles using ferritin molecule

A new process is proposed which exploits protein-supramolecules as scaffolds for producing inorganic, functional nano-structures on a flat surface, and its feasibility is studied. A two-dimensional array of iron-oxide loaded ferritin molecules formed by self-assembly at an air/water interface is transferred onto a hydrophobic Si surface and the protein shell of the ferritin molecule is eliminated by 1 h heat-treatment at 500 degreesC under nitrogen. Scanning electron microscopy (SEM) shows a well-ordered array of nanometer size dots on the Si surface. Atomic force microscopy (AFM) in contact mode indicates that the protein shell is eliminated by the heat-treatment, leaving only the iron cores. Fourier transform IR spectrophotometer (FTIR) analysis and weight measurements also indicate that the protein is selectively removed. From this result, together with the fact that ferritin molecules have the ability to accommodate various kinds of metals and metal complexes, it is feasible that nano-dot arrays suitable for quantum electronic devices can be fabricated by this method, which, in this paper, is called a 'Bio Nano Process'. This newly proposed method will provide more economic mass-production than any other method. (C) 2001 Elsevier Science B.V. All rights reserved.