Current experimental techniques for estimation of the cell surface tension by contact angle measurements were reviewed.
It is shown that in the process of measuring the contact angles of drops of water or air bubbles at biological surfaces, transfer of natural surface active materials to the air/water interface occurs with a consequent reduction in the surface tension. The estimation of cell surface tensions from contact angles based on theoretical calculations in which the air/water tension of pure water is used are in error.
The adhering bubble method is preferable for contact angle determinations in biological systems.