Quantitative measurement of cell migration using time-lapse videomicroscopy and non-linear system analysis.

Epithelial cells of the mammary gland possess the inherent capacity to form epithelial monolayers in vitro. This requires coordination of cell migration, cell-cell contact formation, and cell proliferation. Using time-lapse phase contrast videomicroscopy we have observed mammary gland epithelial cells over different time scales. We show the generation of a complete polarized epithelial monolayer in real-time, starting from a few cells. We subsequently concentrated on the early stages of this process by tracking epithelial cells during phases of polarized migration. We performed migration analysis using fractal measures. With this technology the structure of seemingly random processes not accessible to the usual methods of linear analysis can be measured. As a control and proof of principle approach we applied infection of cells with an adenoviral vector, which is used as a gene targeting vector for many applications. Infection markedly influenced the patterns of migratory behavior. We, therefore, believe that time-lapse videomicroscopy in combination with fractal analysis can contribute to differential characterization of distinct cellular migration patterns. This will be useful in situations of long-term alterations in cell culture systems.