Preparation of La2Sn2O7, Mg2SnO4, and MgSn(OH)6 and their antiviral/antibacterial activities.

In order to develop inorganic antibacterial and antiviral materials that function in the dark, we synthesized La₂Sn₂O₇, Mg₂SnO₄, and MgSn(OH)₆, which are compounds of La₂O₃ and MgO, which have solid basicity, and SnO₂, which has the Mars-van Krevelen (MvK) mechanism. After obtaining each sample as a single-phase white powder through hydrothermal or coprecipitation method, their antibacterial and antiviral activities were evaluated with reference to ISO procedures in the dark for bacteria and viruses with different characteristics. The dependence of activity on the evaluation method suggested that, except for Mg₂SnO₄, the proximity or contact of the viruses or bacteria to the sample surface played an important role in activity. Comparison of the activity of each sample with those of the simple oxides of constituent elements, La₂O₃, MgO, and SnO₂, clarified that pH, solid basicity, phosphate affinity, and the MvK mechanism contribute to antibacterial and antiviral activity. The extent of these contributions varied depending on the sample. The study results revealed that La₂Sn₂O₇ not only exhibits high antibacterial and antiviral activity against bacteria and viruses in the dark; it also has the ability to decompose organic dyes under UV irradiation. This material might be used as a newly developed environmental purification material providing continuous antibacterial and antiviral effects day and night, able to clean surfaces during UV light exposure.