Hydro 2000s unit

The above analyses were performed on cultures of bacteria suspended for 24 h in solutions containing the drug and saponins. The analysis of cell surface properties included evaluation of Congo red binding to microbial cells, according to Ambalam et al. (2012 (link)). Moreover, the cell membrane permeability test using crystal violet was performed, as well as an MTT enzymatic activity test, as described by Smulek et al. (2020 (link)). The zeta potential was calculated from the Smoluchowski equation after measurements of electrophoresis mobility using a Zetasizer Nano ZS instrument (Malvern Instruments Ltd. UK). Additionally, the cells’ sizes were measured using a Mastersizer 2000 instrument (Malvern Instruments Ltd.) equipped with a Hydro 2000S unit that enables the analysis of samples in the form of a wet dispersion. The cells diameters were measured in the range of 0.02–2000 μm. For this purpose, an appropriate quantity of the material was dispersed in a water medium, and after establishing the instrument background, appropriate measurements were made. An atomic force microscope Park NX10 from Park Systems (Suwon, South Korea) was used to analyze changes in the cell topography of the bacteria as described by Pacholak et al. (2023 (link)).