Direct measurement of interaction forces between a yeast cell and a microbubble using atomic force microscopy

Abstract

The removal of adhered cells on surfaces is an important issue in every industrial process. Although bubbles are increasingly being considered for use in cleaning technology due to their positive properties, the cleaning effects of using bubbles and their mechanisms related to interaction forces remain poorly understood. Atomic force microscopy (AFM) is capable of nanoscale force resolution and has been increasingly applied to measure the interaction forces targeting bubbles or biological surfaces. However, few studies have reported on the quantitative measurement of interaction forces between a single microbial cell and a hydrophobic bubble surface. In this study, we attempted to conduct direct measurement of the interaction forces between a yeast cell and a microbubble (MB) using AFM. We demonstrated that the strong adhesive force is attributed to the capillary and hydrophobic forces between a yeast cell and a MB. This force was found to be larger than that between a yeast cell and a stainless-steel substrate. These findings provide useful information for various applications using MBs, including cleaning technology for industrial processes.