US Patent 7803619 Embryoid body-based screen

Disclosed are embryoid bodies having a uniform size of approximately 415 nm and comprising genetically modified embryonic stem cells, and methods of making same. The genetically uniform embryoid bodies can be multiplexed as one embryoid body per well in a multiwell format, and used as a high to medium throughput screen for test agents that affect the development and homeostasis of animals, including humans. The genetic modification of the embryonic stem cells is a promoter-report-selection construct that enables the selection and detection of cells of a particular lineage in the EB, to determine the effects of a test agent.