Photocatalytic inactivation of bacteriophages by TiO2-coated glass plates under low-intensity, long-wavelength UV irradiation

Abstract

The International Organization for Standardization (ISO) was used to evaluate antibacterial activity by titanium dioxide (TiO(2)) photocatalysis since 2006. We evaluated photocatalytic inactivation of Qβ and T4 bacteriophages induced by low-intensity, long-wavelength ultraviolet A (UVA; 0.1 mW cm(-2) and 0.001 mW cm(-2)) irradiation on a TiO(2)-coated glass plate using the ISO methodology. The results indicated that both bacteriophages were inactivated at 0.001 mW cm(-2) UVA. The intensity of UV light, including long-wavelength light (UVA), is very low in an actual indoor environment. Thus, TiO(2) photocatalysis can be beneficial for inactivating viruses in an indoor environment. Experiments using qPCR and bovine serum albumin degradation assume that viral inactivation is caused by outer viral protein disorder and not by viral RNA reduction by reactive oxygen species produced during TiO(2) photocatalysis. Furthermore, we showed that the ISO methodology for standard testing of antibacterial activity by TiO(2) photocatalysis can be applied to assess antiviral activity.

Highly efficient antiviral and antibacterial activities of solid-state cuprous compounds

“…The sample substrate carrying the bacteriophage suspension was set on a U-shaped glass rod in a dish having a wet filter paper at the bottom to keep humidity ( Fig. 1) [13]. After incubation at room temperature under dark conditions, bacteriophages were harvested in 10 mL SM buffer.…”

Photocatalytic activity of Cu2+/TiO2-coated cordierite foam inactivates bacteriophages and Legionella pneumophila

“…Titanium dioxide (TiO 2 ) is an attractive material for the reduction of viral and bacterial infection ratios. TiO 2 undergoes strong oxidization under ultraviolet (UV) irradiation, [8] which can inactivate bacteria and viruses [9][10][11][12][13][14][15][16]. Photocatalysis using TiO 2 is effective in the elimination of toxic substances in water and air [17][18][19].…”

Broad Spectrum Microbicidal Activity of Photocatalysis by TiO2

“…For example, TiO 2 -coated tiles have been used as self-cleaning and antibacterial materials [30]. While we have reported the virucidal activity of photocatalysis for IFV [31] and bacteriophages [32,33], few studies have addressed viruses [34]. Recently non-TiO 2 photocatalysts (i.e., ZnO and ZnS) reported as significant progress archived in development were also observed their antimicrobial activity [35,36].…”