Dear Chandra

I have worked very little on ATC, but of what experience I have, you can use trypsin to make sure disassociate the cells, but in your case as you want to study the cell-matrix association, this would not be a good idea. Lysis of cells directly will be a better option for your study as this is the only way to get a total protein extract for western blot. A simple option can be to take a cell count once placed in the lysis solution and quantify the protein content to make sure you have a total protein extract.

Hope this helps. Best of Luck

Hello

I with " Yash Gupte " in his suggestion , The lysis of cells directly it's a good choice

Good Luck