Objectives To investigate the effect of irradiation on the detection result of the antifungal activity induced by photocatalytic materials and to provide supportive data to establish a standardized detection procedure and to determine a proper intensity and time of irradiation for the detection of the antifungal activity of photocatalytic materials.
Methods The antifungal activity of UV responsive photocatalytic materials was tested under three different levels of irradiation intensity (1.2, 0.8, 0.4 mW/cm2) within the same length of time by using a UV lamp with a wavelength of 365 nm. Three intervals (24, 38 and 48 h) were compared to determine the proper length of irradiation time. The repeatability and stability of this method was tested by independent tests performed by different personnel.
Results The irradiation intensity from 0.4 to 0.8 mW/cm2 had no significant influence on the growth of the test fungi, while the irradiation intensity at 1.2 mW/cm2 had certain harm to the strain. The best duration of discriminating antifungal activity and the most suitable test parameters was conducting the detection after 38 hours of light exposure under an irradiation intensity of (0.4~0.8) mW/cm2. The result tested by different personnel groups proved that this experimental method was simple and feasible, and the photocatalytic antifungal activity value could be repeated.
Conclusions A repeatable test method for the detection of the antifungal activity induced by photocatalytic materials could be established by using an irradiation intensity (of 0.4~0.8) mW/cm2 and irradiating for 38 h. It is the first time that a quantitative determination procedure for photocatalytic antifungal activity by using a film adhesion method was developed. It could effectively fill the blank of the detection method for the antifungal property of photocatalytic materials in China, also provide support data to establish a standard procedure and help to improve the technical level of photocatalytic industries.
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