Highly polar or ionisable chemical groups increase latex stability and facilitate covalent protein coupling to the microsphere surface.
The groups –COOH are produced by copolymerisation of the corresponding functional monomers. For carboxylated latexes, eliminating surfactant and lowering of the pH decreases latex stability and may trigger partial flocculation. In this case, we recommend diluting the latex further and slowing the stirring. If the result is still unsatisfactory, a non-ionic emulsifier may be added (0.1 to 0.5 g/L of TWEEN 20).