We have recently developed the MicroColonyChip, a new cell survival platform that uses a novel metric: colony size (Cell Reports, 2019).
The ‘gold standard’ for quantification of cytotoxicity is the colony forming assay. This assay requires that colonies grow long enough to form visible colonies that are then counted manually. We have created a new approach that enables miniaturization and automation. Instead of waiting for visible colonies, microcolonies are grown in tiny micron scale wells in agarose. The resulting microcolony array is then imaged and the size distribution of the colonies is derived using automated image analysis software, greatly reducing labor associated with colony counting using the gold standard assay. Results from the MicroColonyChip are indistinguishable from results using the gold standard colony forming assay, which demonstrates that the MicroColonyChip is exquisitely sensitive.
The MicroColonyChip assay is also as sensitive as the Cell TiterGlo assay, yet is fully automated and robust to artifacts. For example, depending on the number of cells used to seed the Cell TiterGlo assay, results are highly variable. In contrast, the MicroColonyChip gives rise to consistent results over orders of magnitude differences in seeding density. Furthermore, Cell TiterGlo is a measure of metabolic activity, whereas the MicroColonyChip is measuring the actual number of cells, making the assay resistant to artifacts caused by conditions that impact cellular metabolism.