Polyclonal antibody was immobilized on the NC
membrane by the following steps. First, the NC
membrane was saturated in 10% (v/v) methanol in water
for 45 min and left to dry. The membrane was then
treated in 0.5% (v/v) glutaraldehyde for 1 h. After
drying, 0.5 mg/ml of the polyclonal antibody was
pipetted on the membrane, and incubated at 378C for
1 h. Inactivation of residual functional groups and
blocking was carried out simultaneously by incubating
the membrane with 0.1 M tris buffer, pH 7.6, containing
0.1% Tween-20 for 45 min. The membrane was allowed
to air-dry.