Figure 1.

Experimental design for tagging antibodies with metal-chelating polymers. The antibody of interest is subjected to selective reduction of -S—S-groups to produce reactive -SH groups, which are reacted with the terminal maleimide groups of a polymer bearing metal-chelating ligands along its backbone. The polymer-bearing antibodies are purified, treated with a given lanthanide ion, and then purified again. Each type of antibody is labeled with a different element.