Large-scale single-cell trapping and imaging using microwell arrays

High-throughput single-cell measurements of cellular responses are of great importance for a variety of applications including drug testing, toxicology, and basic cell biology. We present an optimization study for trapping single cells with high efficiency in large arrays of microwells. The method is compatible with standard fluorescence microscopy equipment and is not dependent on, but is compatible with, cell adherence. We have characterized microwell occupancy by cells for a range of microwell dimensions and seeding parameters and optimized it for fibroblasts (as a model of adherent cell) and rat basophilic leukemia cells (as a model of nonadherent cell). We have been able to obtain phase-contrast and fluorescence micrographs with more than 18 000 single cells per image using a 4x objective.