I am currently using transwell inserts with the addition of 50 uL of matrigel for an invasion assay with various osteosarcoma cell lines.
I have tried various dilutions of matrigel and all result in the cells clumping into a spheroid on top of the matrigel within under 24 hours. Originally I thought this was not a problem, but it makes for very inconsistent results.
I am wondering if there is a coating or method of cell seeding that allows cells to invade in a more uniform way through the matrigel towards the well below the transwell insert.