4.6. Optimization of Generic Immuno-Magnetic Bead-Based Enzyme-Linked Immunoassay

OD value of indirect noncompetitive ELSA was used to evaluate immunoassay performance and to reveal the influence of multiple factors on reaction of the antigen–antibody complex. Multiple factors were investigated such as time length of the activation (1, 2, and 4 h) and the conjugation (1, 2, 3, 4, 5, 6, 8, and 10 min) between the immunomagnetic beads and antibody, blocking regent (5% OVA, 5% BSA, and 5% skim milk powder), time length of competitive reaction (30, 45, and 60 min) in the immuno-magnetic bead enzyme-linked immunoassay procedures, and pH (5.0, 6.0, 7.0, 7.4, 8.0, 9.0, and 10.0) of the competitive reaction solution.

It should be noted that the only difference between immuno-magnetic bead-based ELISA and the traditional ELISA lay in that the generic antibody was used directly for the traditional ELISA, whereas the immunomagnetic beads were used for the immuno-magnetic bead-based ELISA.