Amorphous TiO2 nanoparticles: Synthesis and antibacterial capacity

In this work, the sol-gel method was used to synthesize titanium dioxide (TiO2), a process that allowed elaboration of the different phases of TiO2, in a controlled manner through heat treatments, ensuring the purity of the oxide and the nanometric size of the particles. The results of X-ray diffraction (XRD) showed that the synthesized powders were amorphous up to a temperature T < 350 °C, with a particle size of ~ 100 nm, determined by electron microscopy (TEM and SEM). Considering the nature of the synthesis process used, a mechanism was put forward that would allow explanation of the formation of amorphous TiO2 nanoparticles (TiO2-ANPs). With the aim of studying the potential use of the synthesized TiO2-ANPs, their antibacterial capacity was studied. The inactivating effect on bacteria of synthesized amorphous TiO2 was analyzed by recording the effect of its presence on bacterial strains of Escherichia coli. As such, prior to the addition of amorphous TiO2 to the culture of E. coli, the oxide was activated by subjecting it to UV radiation for 1 h. The activated amorphous TiO2 was immediately then placed in contact with the culture, which was not irradiated with UV during the course of this test. The results indicate that in the first 30 min of exposure of the bacteria to the activated amorphous TiO2, the presence of E. coli colonies was significantly reduced, with no presence being detected in the culture.