Large-scale time-lapse microscopy of Oct4 expression in human embryonic stem cell colonies

• Quantitative characterization of growth rate and other parameters over hundreds of stem cell colonies
• Tracking of Oct4 expression through green fluorescent protein over hundreds of colonies at close to cell resolution
• Identification of rare events that would be easily missed by visual inspection of a very large data set

Identification and quantification of the characteristics of stem cell preparations is critical for understanding stem cell biology and for the development and manufacturing of stem cell based therapies. We have developed image analysis and visualization software that allows effective use of time-lapse microscopy to provide spatial and dynamic information from large numbers of human embryonic stem cell colonies. To achieve statistically relevant sampling, we examined > 680 colonies from 3 different preparations of cells over 5 days each, generating a total experimental dataset of 0.9 terabyte (TB). The 0.5 Giga-pixel images at each time point were represented by multi-resolution pyramids and visualized using the Deep Zoom Javascript library extended to support viewing Giga-pixel images over time and extracting data on individual colonies. We present a methodology that enables quantification of variations in nominally-identical preparations and between colonies, correlation of colony characteristics with Oct4 expression, and identification of rare events.