The evaluation of antibacterial activity is performed by a procedure based on the international standard ISO 27447: 2019 "Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for antibacterial activity of semiconducting photocatalytic materials". According to the standard, photocatalytic surfaces that come in contact with a bacterial solution are exposed to ultraviolet irradiation and the decrease of survived colonies is recorded in comparison to non-irradiated and non-photocatalytic surfaces. A schematic illustration of sample arrangement, as well as a typical photograph of colonies, which survived on non-photocatalytic and photocatalytic surface after irradiation are shown in Figure 1.

Figure 1. Sample arrangement (a) and a photograph of viable colonies after irradiation of photocatalytic and non-photocatalytic surfaces (b).