Wound Healing Assay of Two Competing Cell Types with Dry Mass Measurement

Wound healing assay is a method for evaluating of cells migration rate in vitro. In this assay, a scratch is performed in a confluent cell monolayer that usually contains only one type of cells. Interferometric phase microscopy (IPM) is an imaging technique, by which the optical path difference (OPD) of a sample is extracted. The OPD equals to the thickness of the sample multiplied by its integral refractive index, and therefore provides us with quantitative information about the sample. Fluorescent probes are fluorescent compounds that can be attached to specific cells in order to provide ability of imaging the cells with specific contrast enhancement under fluorescence microscope. Using a fluorescent microscope combined with an interferometric phase microscope, wound healing assay of a cell confluent monolayer that contains two types of cells is performed, while one type of cells is labeled with fluorescent probes for differentiation purposes. This allows us to check which cell type closes the wound faster, and, for the first time, measure each cell population dry mass during this process.