Does anyone know exactly how the antibodies/antigen molecules are bound to the inside of the microtitre wells in the first step of the ELISA? I have done some research and can’t seem to find the mechanism by which they are attatched.
I think it is mostly non-specific, electrostatic interactions. Many proteins spontaneously stick to plastics like polystyrene, less so to polypropylene. This is how the indirect ELISA plate is set up, as chen.lie described. Once you’ve bound the reagent of interest, you usually then have to block as much of any remaining potential non-specific sites by washing, then adding an excess of some general protein like albumin or gelatin, and then washing again.