Trouble transfecting HEK 293 T and HUH 7 cells - (Aug/08/2015 )

Greetings people

I am struggling with cell culture. It is my first time. Every time i seed my hek 293t cells for transfection they always clump in the middle, why? I do rock my plates in  "+" motion. My supervisor says it has to do with the vibrations in the hood and incubators. But it doesnt happen to every one in the lab. will it affect my transfections? with my huh 7s they seed proper no clumping, however after transfection the cells in the middle of the well are dead only the cells on the outskirts survive, why is this? 

Hello there, 

This is a very common problem among people who do cell culture. Personally, I notice more of this kind of clumping when my cells have been passaged many times so firstly, try taking out a fresh batch of cells from the freezer.

Secondly, watch your trypsinization before seeding and make sure your cells have been well-dissociated. Incomplete dissociation and seeding of cell-clumps naturally makes cells grow into packed islands after 24 hours.

Remember, happy cells make a homogenously distributed monolayer. A small amount of gathering in the middle of your coverslip is normal but dense packs with dying cells is not.