Survival of Staphylococcus aureus exposed to UV radiation on the surface of ceramic tiles coated with TiO2

Abstract

The aim of this study was to determine and compare the antimicrobial activity of UV radiation of wavelength 253.7 nm (used in typical germicidal lamps) against Staphylococcus aureus on the surfaces of conventionally produced white ceramic wall tiles (matt and shiny) and the same tiles coated with TiO 2 using three different methods: RF diode sputtering, atmospheric pressure chemical vapour deposition (APCVD) and spray pyrolysis deposition (SPD). Results clearly indicate that the bactericidal action of UV radiation is much stronger on the surfaces of tiles coated with TiO 2 than on the tiles uncovered. The strongest bactericidal effect of UV radiation was found for film prepared by APCVD. Results of experiments for shiny and matt tiles did not differ statistically. The use of ceramic wall tiles coated with TiO 2 films in hospitals, veterinary clinics, laboratories, food processing plants and other places where UV radiation is applied for disinfection should greatly improve the efficiency of this treatment.

Chances and limitations of nanosized titanium dioxide practical application in view of its physicochemical properties

“…In recent years, numerous studies have been focused on the aspect of using the photocatalysis phenomenon in eradication of pathogenic microorganisms in ventilation systems [ 82 , 97 - 99 ], water supplies [ 27 , 29 , 32 , 82 , 100 - 103 ], sewage systems [ 104 , 105 ] and on work surfaces (e.g. tables and floors) in medical centres [ 15 , 16 , 106 ] or in food processing plants [ 107 , 108 ]. Among the photocatalytic processes that have been most studied in the context of microorganism inactivation and degradation of toxic compounds to human and animals is the TiO 2 /UV process where titanium dioxide (TiO 2 ), after it has been powdered to nanoparticles, performs as photocatalyst, and ultraviolet (UV) radiation is an agent generating reactive oxygen species [ 10 ].…”

“…According to Szczawiński et al [ 107 , 108 ] as well as Tomaszewski and Jach [ 62 ], the number of living cells of E. coli , P. aeruginosa , Salmonella Enteritidis and S. aureus on the floor and wall ceramic tiles (applied in production halls, hospital rooms or sanitary rooms) covered by a thin layer of nano-TiO 2 and exposed to UV radiation for 2 min was reduced by 6 to 7 logarithmic units, depending on the method of photocatalytical layer deposition and on the kind of tiles (shiny or matt). On control surfaces, the bacteria reduction rate amounted to around 1 logarithmic cycle.…”

Chances and limitations of nanosized titanium dioxide practical application in view of its physicochemical properties

“…As Szczawiński et al [107,108] report, the application of photocatalytic surfaces, such as of ceramic wall tiles covered by a thin layer of nano-TiO2, in food processing plants, veterinary clinics, hospitals, treatment rooms, laboratories and wherever the UV radiation to disinfect surfaces is put to use, should significantly increase the disinfection effectiveness and contribute to a dramatic improvement of hygiene conditions in those areas. It has been pointed out for many years that photocatalytic Unauthenticated Download Date | 6/7/19 1:40 AM processes can become a tool of a permanent surface disinfection of those items that people are in frequent contact with, e.g.…”

“…According to Szczawiński et al [107,108] as well as Tomaszewski and Jach [62], the number of living cells of E. coli, P. aeruginosa, Salmonella Enteritidis and S. aureus on the floor and wall ceramic tiles (applied in production halls, hospital rooms or sanitary rooms) covered by a thin layer of nano-TiO2 and exposed to UV radiation for 2 min was reduced by 6 to 7 logarithmic units, depending on the method of photocatalytical layer deposition and on the kind of tiles (shiny or matt). On control surfaces, the bacteria reduction rate amounted to around 1 logarithmic cycle.…”

“…In recent years, numerous studies have been focused on the aspect of using the photocatalysis phenomenon in eradication of pathogenic microorganisms in ventilation systems [82,[97][98][99], water supplies [ 27,29,32,82,[100][101][102][103], sewage systems [104,105] and on work surfaces (e.g. tables and floors) in medical centres [15,16,106] or in food processing plants [ 107,108]. Among the photocatalytic processes that have been most studied in the context of microorganism inactivation and degradation of toxic compounds to human and animals is the TiO2/UV process where titanium dioxide (TiO2), after it has been powdered to nanoparticles, performs as photocatalyst, and ultraviolet (UV) radiation is an agent generating reactive oxygen species [10].…”