Microcolony Size Distribution Assay Enables High-Throughput Cell Survival Quantitation

Abstract

Summary: Cell survival is a critical and ubiquitous endpoint in biology. The broadly accepted colony formation assay (CFA) directly measures a cell’s ability to divide; however, it takes weeks to perform and is incompatible with high-throughput screening (HTS) technologies. Here, we describe the MicroColonyChip, which exploits microwell array technology to create an array of colonies. Unlike the CFA, where visible colonies are counted by eye, using fluorescence microscopy, microcolonies can be analyzed in days rather than weeks. Using automated analysis of microcolony size distributions, the MicroColonyChip achieves comparable sensitivity to the CFA (and greater sensitivity than the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide [XTT] assay). Compared to CellTiter-Glo, the MicroColonyChip is as sensitive and also robust to artifacts caused by differences in initial cell seeding density. We demonstrate efficacy via studies of radiosensitivity and chemosensitivity and show that the approach is amenable to multiplexing. We conclude that the MicroColonyChip is a rapid and automated alternative for cell survival quantitation. : The gold standard for cytotoxicity testing is the colony formation assay (CFA), which requires visible colonies in large dishes. Ngo et al. describe the MicroColonyChip, which directly measures the ability of cells to divide. This automated miniaturized assay retains the sensitivity of the CFA and takes days instead of weeks. Keywords: colony formation assay, cell proliferation, miniaturization, fluorescence microscopy, high-throughput cytotoxicity assay, anti-cancer efficacy, drug safety, cytotoxicity, multiplex assay