Compressive testing of single yeast cells in liquid environment using a nanoindentation system

Abstract

Due to their versatility and accuracy, nanoindentation systems are increasingly used for the characterization of micron-sized particles. Single microbial cells (e.g., yeast cells) can be regarded as micron-sized, liquid-filled biological particles. Applying a nanoindentation system for the compressive testing of those cells offers many options, such as testing in liquid environment. However, diverse experimental problems have to be resolved, especially the visualization of the cells in liquid and the alignment of the surfaces between which the cell is compressed. Single yeast cells were tested using a nanoindenter equipped with a flat punch tip. The deformation behavior of the cells during loading as well as the shape recovery behavior during unloading was investigated. A bursting force was determined as the cell wall was failing at higher deformations. Moreover, the influence of the compression speed on the cell mechanical behavior was characterized.