chemist27 said:

I am currently seeding endothelial cells on Matrigel and hoping to analyze tube length (angiogenesis assay). I am having trouble with cell clumping. Any ideas on keeping a good, single cell suspension? Any other good tips on improving this assay? thanks!

Try reducing the % of matrigel you use when making the gel. In other words, dilute the matrigel with the media of your choice to 20-75%. I believe I've seen cell lines form abnormal aggregates on pure matrigel and that it can be stopped if the matrigel is diluted.