Hi

I'm using pluripotent stem cells to induce hematopoietic stem cells. We use APEL media containing 20ng/ml BMP4, 20ng/ml VEGF and 40ng/ml SCF. We seed around 10,000 cells/well in 96-well plate, then spin the plate to form embryoid body (EB). Sometimes we observed doughnut like EB with empty center after couple days induction in some cell lines. Does anyone know what this doughnut EB means?

We usually run FACS to check PDGFRa and CD34 to marker. It seems the doughnut EB dont't express PDGFRa marker. Could we conclude this doughnut as failed induction?

Thanks!