Thank you Dr. Kiss, I would like share my idea with you.
my primary concern is to initiate the culture, after that I am going to seed into 96-well with/wihtout collagen-I coating (200ug/ml) and incubate for 4hrs. Then will be treating with Angiopoietin-1 (50ng/ml) and TNF-a (10ng/ml) to assess ROS generation.
So, for initiating the culture on 100mm dish or T25 flask do I really need to coat the bottom with gelatin?
What I can say from my personal experience, for this kind of experiment with HUVEC-ST cell line, it is not necessary to coat the bottom of culture dish and/or flask. I have successfully cultured these cells without it.
Gelatin is better for attachment than cell culture plastic is most cases (depending on FBS lot, for example). More importantly, check that your HUVEC haven't lost responsiveness to your stimuli due to high passage number. For some assays, HUVEC work well for about 7-8 passages. For other responses, maybe 4-5. Good luck!
Yes, indeed, Paulina is right: you can culture HUVECs without any coating but gelatin in any case will provide you with better results because it helps HUVECs against anoikis.