Optimized antimicrobial and antiproliferative activities of titanate nanofibers containing silver

Figures & data

Figure 1 TEM images and digital camera photographs of protonated pentatitanate (H₂Ti₅O₁₁ · H₂O) (A and E), titanate after Ag⁺ cations exchange (B and F), partial reduction of Ag⁺ cations from the layered space with the UV light irradiation (C and G), and reduction of Ag⁺ cations with NaBH₄ agent (D and H).

Figure 2 High resolution TEM image of Ag/titanate nanocomposite formed by UV light irradiation (300 W Xe, 320–400 nm).

Figure 3 X-ray photoelectron spectroscopy spectra of Ag 3d: (A) titanate after Ag⁺ cation exchange, (B) partial reduction of Ag⁺ cations from the layered space with UV light irradiation, and (C) reduction of Ag⁺ cations with NaBH₄ agent.

Abbreviation: au, arbitrary units.

Figure 4 UV-visible absorption spectra of (A) protonated pentatitanate (H₂Ti₅O₁₁ · H₂O), (B) titanate after Ag⁺ cations exchange, (C) partial reduction of Ag⁺ cations from the layered space with the UV light irradiation, and (D) reduction of Ag⁺ cations with NaBH₄ agent.

Figure 5 Comparison of the inhibition zone test for the titanate-based compounds: Ag/titanate by NaBH₄ reduction (A), Ag/titanate by UV light irradiation (B), Ag₂Ti₅O₁₁ · xH₂O (C), and pure H₂Ti₅O₁₁ · H₂O (D).

Figure 6 Antifungal (A) and antiproliferative (B) activities of titanate-based compounds, which are Ag/titanate by NaBH₄ reduction, Ag/titanate by UV light irradiation, Ag₂Ti₅O₁₁ · xH₂O, and pure H₂Ti₅O₁₁ · H₂O.

Scheme 1 Schematic representations of “nutrients from galleries” principle to generate Ag/titanate nanocomposites: (A) represents the pristine protonated pentatitanate (H₂Ti₅O₁₁ · H₂O); (B) silver titanate (Ag₂Ti₅O₁₁ · xH₂O) prepared by exchange of protons with Ag⁺ cations; partial (C) or fully (D) Ag⁺ cations exchange with protons in the layered space and the formation of the silver nanoparticles on titanate substrates with the redox process. The unit cell (a–d; enclosed by dotted lines) are C-based centered monoclinic, which is projected along [010] direction.

Note: Open and filled circles indicate the locations at y = 0 and ½, respectively.