Measuring accurately liquid and tissue surface tension with a compression plate tensiometer

TL;DR

This paper evaluates and improves methods for accurately measuring tissue surface tension with a compression plate tensiometer, highlighting the importance of contact angle measurement and introducing a new local polynomial fit method.

Contribution

It compares existing measurement methods, tests their assumptions, and proposes a novel LPF method that reduces dependence on contact angle accuracy.

Findings

Existing methods are sensitive to contact angle measurement errors.

The new LPF method provides more robust and accurate surface tension measurements.

Many reported tissue surface tension values may be inaccurate due to improper handling of contact angle.

Abstract

Apparent tissue surface tension allows the quantification of cell-cell cohesion and was reported to be a powerful indicator for the cellular rearrangements that take place during embryonic development or for cancer progression. The measurement is realized with a parallel compression plate tensiometer using the capillary laws. Although it was introduced more than a decade ago, it is based on various geometrical or physical approximations. Surprisingly, these approximations have never been tested. Using a novel tensiometer, we compare the two currently used methods to measure tissue surface tension and propose a third one, based on a local polynomial fit (LPF) of the profile of compressed droplets or cell aggregates. We show the importance of measuring the contact angle between the plate and the drop/aggregate to obtain real accurate measurement of surface tension when applying existing methods. We can suspect that many reported values of surface tension are greatly affected because of not handling this parameter properly. We show then the benefit of using the newly introduced LPF method, which is not dependent on this parameter. These findings are confirmed by generating numerically compressed droplet profiles and testing the robustness and the sensitivity to errors of the different methods.