hey thanks for the comments everyone. Yes this is trypan blue, which in hindsight, was not the best choice with the background... The flash was on camera, as I don't currently have an off-camera flash setup (I do agree that it makes it a bit too harsh).
A great idea, definitely appropriate for the challenge. The lighting could be a little less harsh, though. It appears to be taken with an on-camera flash, which looks really unnatural, and the dark tube blends right into the black background. It might work better if the angle were changed so that the tube was entirely in front of the fog, instead of the background.
shot is just sort of weird, and the right third just seem like wasted space. doesn't really say "biology" to me. mad scientist maybe, but not biology. ;) sorry - 3