Effect of moisture equilibration time and medium on contact angles of bacterial spores

- Contact angle measurement does depend on some critical points in preparation.
- The moisturizing medium lowers resulting water contact angles when glycerol is present.
- Without glycerol, time span for equilibration has no significant influence on results.

Contact angle measurement of microorganisms is often described in literature, either to investigate their hydrophobic characteristic or the adhesion behavior of cells. However, in some key aspects the preparation methods differ. Thus, it is difficult to compare results and to choose a procedure for repetition of measurements. The aim of this paper is to point out some critical points during microorganism film preparation that can alter the resulting contact angles. Depending on the moisturizing medium and equilibration time, contact angles differ significantly.