I'm physicist by training, so please excuse me if I don't use the proper terminology.
I think there is a way to make a sensor that detects if a single antibody has caught something from the flow. So I'm trying to figure out if this would be a useful sensor, but this depends on how specific the antibodies really are.
When I ask biologists "How specific are antibodies?", they reply: "Very-very specific", but provide no values that I understand on microscopic level. But I am trying to make a quantitative estimation, e.g. for the following thought experiment:
Suppose I have attached an antibody to inorganic surface. It's an antibody for catching object X. And I flow blood over the surface, slowly. Suppose there's no X in this blood at all. But there are lots (maybe 1017, or some crazy number like that) of other stray particles flowing by this antibody every second, right? So, when one of these particles bumps into this one antibody, what is the probability that it would stick to this antibody? Is it really 10-17 ? Is it really so small?
And, in any case, how do I estimate this probability at least to 1-2 orders of magnitude?
Also, how do I estimate the "collision cross section area" through which an object has to fly to make an attempt to bind to an antibody? In other words, does it only have to touch it slightly, or bump into antibody in a hard and messy collision?
Does the probability of successful bind depend on the flow speed?
How would the values change if I take serum instead of blood?
Could you please point to some relevant papers, books or just keywords? I would very much appreciate any help.