*2.3. Deposited-Drop Experiment*

To avoid damage by UV irradiation alone [49], the maximum UV intensity was maintained at 2.5 W/m2 . Previous tests with higher UV intensity had shown total drying of the inoculum during the experiment and led to the inactivation of bacteria in control samples. The light intensity was measured on the samples using a UV-A radiometer (Gigahertz-Optik, GmbH Türkenfeld, Germany) in the 310–400 nm range.

Various configurations were studied: samples under UV irradiation (TiO2-bearing samples and control specimen without TiO2) and samples kept in the dark (TiO2-bearing samples and control specimen without TiO2). All tests were carried out in triplicate. The data shown are the average of triplicates, with the corresponding standard errors.
