Mesoporous TiO2 synthesis using a semi-hard biological template

The bacteriophage M13, a rod-shaped virus, was used as a semi-rigid template to synthesize crystalline mesoporous TiO2. This strategy allowed us to modulate sol-gel reactions on the virus surface without the need of chemical or genetic manipulation. Important parameters as pH influence and concentration were investigated. The studies by which the pH was varied were the principal route to obtain materials with pores of around 6.1 and 8.2 nm. When an M13 phage concentration of 0.1 mg/mL was employed, anatase mesopores presented specific surface areas from 80 to 130 m2/g and pore volumes from 0.18 to 0.21 cm3/g. It should be mentioned that surface area is due exclusively to mesopores, and from N2 adsorption/desorption experiments, no evidence of micropores was detected. This absence of micropores results from the stable protein arrangement on M13 phage, which contrasts with the disruption of micellar assemblies of soft templates. These results show that anatase mesophases are obtained in an easy and rapid route at room temperature and could be expanded to synthesize other metal oxide mesostructures tuning M13 phage properties.