I'm working on sandwich-type ELISA for virus detection (capture antibody captures virus, probe antibody then binds to captured virus, signal molecule then binds to probe antibody, then plate is read) and am having trouble finding the right blocking agent to use.
So far, we've tried combinations of casein, PVP, and gelatin and none seem to give us a signal to noise ratio we can work with. Have any of you used any blocking agents or combinations of blocking agents that I'm missing, beyond simply BSA or something of the like?
I think it may be an issue of insufficient washing, as we only do three wash steps after incubating the virus and two after incubating the probe antibody. However, I'm afraid more washing could disrupt antibody binding to the virus or the walls.
Any suggestions? Thanks in advance!
Edited by PipetteTip, 06 July 2010 - 03:43 PM.