Effect of gallium and strontium salts on the characteristics and biological applications of Sr and Ga-modified titanate nanotubes

In this work, we report the synthesis of Na-TiNTs sodium titanate nanotubes prepared by the hydrothermal method in a highly alkaline subsequently modified by the substitution of Na+ ions present in the walls of the nanotubes by ions of Sr2+ and Ga3+ revealing the presence of phases such as SrOH2 and α-GaOOH through the analysis by X-ray diffraction. Raman spectroscopy showed the characteristic peaks of the vibrational modes of the titanate nanotube structure. UV–Vis analysis revealed a blueshift of absorption edge that leads to an increase in the bandgap with the insertion of Sr and Ga ions. The ion exchange causes a decrease in the Urbach energy, which suggests a certain attenuation in the concentration of structural defects.Through the SEM images it is observed the cluster of interwoven nanotubes it self is characteristic of titanate nanotubes and, the elemental mapping shows the complete efficiency of the reaction process of sodium ion exchange by strontium and gallium in the Sr-TiNT and Ga-TiNT samples respectively, showing the environment of the chemical composition of the surface with the presence of chemical elements such as Sr, Ga. The Na-TiNT, Sr-TiNT, and Ga-TiNT nanotubes did not show direct antibacterial activity against the tested strains. The Na, Ga, and Sr TiNTs of the ampicillin antibiotic exhibited significant values against the microorganism S. aureus 10 compared to the control antibiotic, thereby reducing its inhibitory concentration. The same was observed for gentamicin. The Na-TiNT, in combination with gentamicin, displayed a reduction in inhibitory concentration compared to the control for P. aeruginosa 24. In E. coli 06, the Na, Sr, and Ga TiNTs showed a reduction in concentration when combined with gentamicin, indicating a potential synergistic effect.