Harnessing designer biotemplates for biomineralization of TiO₂ with tunable photocatalytic activity

Biomineralization is a promising material synthesis strategy for environmentally benign production of nanostructured metal oxides. An important question is whether biomineralization can be used in the biomimetic synthesis of TiO₂ with tunable photocatalytic properties that are conducive to diverse solar energy conversion applications. Here, we report the biomineralization of energy-state-modified TiO₂ nanoparticles, where the critical properties closely related to their photocatalytic activity can be manipulated by tailoring the nature of the designer biotemplates. For this purpose, STB1 heptapeptide was employed as a nucleation center to induce TiO₂ biomineralization. Three distinctive types of biomolecules (peptide, protein, and phage) were deliberately designed to contain the STB1 nucleation core at different local densities and intermolecular distances. The degree of substitutional nitrogen-doping and the morphology are all subject to the context-dependent differential availability of STB1 in the biomineralization milieu. Phage-induced biomineralization results in TiO₂ with modified energy state and wire-like network morphology, which account for significantly enhanced charge dissociation/transport performance and high photocatalytic activity. This is the first study to report that a specific peptide with biomineralizing activity exerts differential impacts on the properties of resulting biomineralization products in a context-dependent manner, and will provide a powerful new strategy for tailoring of material properties via biomineralization.