I'm trying to culture primary endothelial cells after isolation, but I'm struggling with adhesion. I've tried coating the glass with poly-L-lysine, gelatin, and fibronectin, but the cells still won’t attach well — they either float or detach during gentle washing steps.

If you’ve worked with primary endothelial cells (especially from resistance arteries or similar small vessels), I’d really appreciate any advice on:

• Coating strategies that worked for you
• Media supplements or additives that improve early adhesion
• Tricks to improve plating success

Thanks in advance!