We have succeeded in aligning gold nanoparticles (Au NPs) in three-dimensions using tobacco mosaic virus (TMV) in
order to realize new optical properties. TMV is a tube-shaped plant virus about 300 nm in length with an outer- and
inner-diameter of 18 nm and 4 nm. We genetically fused material-binding peptides that can promote metal
crystallization, namely a gold-binding peptide (GBP) and a titanium-binding peptide (TBP), to the outer-surface of
TMV. By reducing potassium chloroaurate with sodium borohydride in the presence of the engineered viruses in 5%
acetic acid solution, Au NPs were deposited on the outer-surface of the viruses. Using TBP-fused TMV, NPs of 5 nm
were obtained, with a standard deviation smaller than those deposited on wild-type TMV. The diameter of the NPs on
GBP-fused TMV was 10 nm. These results indicate that genetically-modified TMVs are promising templates for the
construction of optical metamaterials.
The biology and semiconductor technology have progressed independently. There was a large distance between them and a substantial interdisciplinary research area was left untouched. Recently, this situation is changing. Some researchers are stimulating semiconductor technology to introduce bio-molecules into the nano-fabrication process. We proposed a new process for fabricating functional nano-structure on a solid surface using protein supramolecules, which is named “Bio Nano Process” (BNP). We employed a cage-shaped protein, apoferritin and synthesized several kinds of nanoparticles (NP) in the apoferritin cavity. A two-dimensional array of them was made on the silicon wafer and this array was heat treated or UV/ozone treated. These processes produced a two-dimensional inorganic NP array on the silicon surface. The size of NP is small enough as quantum dots and the floating nanodots memory using this NP array is now under development. We also proposed another process using the obtained nanodot array as the nanometric etching mask. This was realized by the neutral beam etching and 7nm Si nano columns with high aspect ratio were fabricated. These experimental results demonstrated that the BNP can fabricate the inorganic nanostructure using protein supramolecules and the BNP opened up a biological path to nanoelectronics devices.