Thermosensitive magnetic particles as solid phase support in an immunoassay

The adsorption and the chemical grafting of an antibody (anti-Alpha-foeto p rotein) onto thermosensitive magnetic latex particles has been investigated as a function of pH, ionic strength and temperature. The hydrophilic magne tic latexes bearing surface carboxylated groups have been prepared on the b asis of an heterocoagulation concept. The adsorption of the antibody (anti- Alpha-foeto protein) was found to drastically decreased upon increasing the pH, whereas, the effect of ionic strength was found to be negligible in th e studied range. The covalent coupling of the antibody was performed using two cardodiimide and succinimide derivatives. The prepared conjugates (late x-antibody) were evaluated by performing the classical Enzyme Linked Immune Sorbent Assay (ELISA) for detecting the Alpha-foeto protein (AFP).