Reusable immunomagnetic beads in an enzyme immunoassay

Multiple antigen peptides (MAPs) were synthesized according to the epitope sequence of human cytomegalovirus phosphoprotein pp150 and used as antigens to coat the surface of Dynabeads M-450 Tosylactivated covalently. The coating efficiency peaked at 79% when the concentration of MAP8 was 100 mu g/ml. Based on the immunomagnetic beads, an enzyme immunoassay was established to detect anti-MAP8 immunoglobulin G in sera of Balb/c mice, which were immunized with MAP8. We showed in this study that, with optimized working conditions, the immunomagnetic beads could be regenerated after removal of the antibody complexes from their surface with 0.2 M citric acid buffer (pH 2.5) and reused at least 16 times without significantly influencing the antibody binding efficiency. The results suggest the possibility of developing reusable immuno-diagnostic kits in the near future.