Elemental composition control of gold-titania nanocomposites by site-specific mineralization using artificial peptides and DNA

Biomineralization, the precipitation of various inorganic compounds in biological systems, can be regulated in terms of the size, morphology, and crystal structure of these compounds by biomolecules such as proteins and peptides. However, it is difficult to construct complex inorganic nanostructures because they precipitate randomly in solution. Here, we report that the elemental composition of inorganic nanocomposites can be controlled by site-specific mineralization by changing the number of two inorganic-precipitating peptides bound to DNA. With a focus on gold and titania, we constructed a gold-titania photocatalyst that responds to visible light excitation. Both microscale and macroscale observations revealed that the elemental composition of this gold-titania nanocomposite can be controlled in several ten nm by changing the DNA length and the number of peptide binding sites on the DNA. Furthermore, photocatalytic activity and cell death induction effect under visible light (>450nm) irradiation of the manufactured gold-titania nanocomposite was higher than that of commercial gold-titania and titania. Thus, we have succeeded in forming titania precipitates on a DNA terminus and gold precipitates site-specifically on double-stranded DNA as intended. Such nanometer-scale control of biomineralization represent a powerful and efficient tool for use in nanotechnology, electronics, ecology, medical science, and biotechnology. Biomineralization allows for crystal structure, size, and morphology control over inorganic compounds, but precipitation at random compositions hinders the construction of complex nanostructures. Here, the elemental composition of a gold-titania nanocomposite photocatalyst is controlled through two inorganic precipitating peptides bound to DNA.

Automated summary

Biomineralization allows for control over crystal structure, size, and morphology of inorganic compounds, but random precipitation hinders the construction of complex nanostructures. The elemental composition of a gold-titania nanocomposite photocatalyst is controlled through two inorganic precipitating peptides bound to DNA.