soft agar assay - cells in the top agar cells adhere to the plates unexpectedly. (Aug/31/2010 )

Hi, everybdy!
I've done soft agar assay for several times. However, I've got a trouble that cells in the top agar cells adhered to the plate unexpectedly a few days after I seeded the cells .

The following was My protocol.
1. Prepare 0.5% base agar layer and store the plate at 4°C.let it sit at room temp for 30 min before using.
2. Prepare 0.6% top agarose solution
3. Harvest and count cells
4. Respend the appropriate number of cells in top agar . Final concentration of top agarose solution was 0.3%.
5. Incubate for 10-30 days and feed cells 2 times a week.

Did anybody have experiences?
What's the reason for the phenomenon that cells in the top agar cells adhered to the plate unexpectedly?

Nobody konw?

what sort of cells you are using?

Thanks for your reply.
I use murine barrow marrow mesenchymal stem cell.
Do you have any suggestions?

Hello Zhu, now I am experiencing similar problem i.e. cells in the top agar cells adhered to the plate. Did you find out the solution? Please let me know