8.2. Immuno-strip
Use of a different format like ELISA, using a nitrocellulose-strip rather
than microtiter wells,
led to the development of lateral flow strip/dipstick/immuno-strip technology.
Immobilized double antibodies,
specific to recognize expressed protein are conjugated to a color reactant (gold nano-particles) and incorporated into a nitrocellulose strip.
This nitrocellulose strip when dipped in the protein extract of plant tissue (e.g. GM cotton leaf) harboring a GM protein, leads to an antibody reaction releasing color.
This red colored gold conjugated complex flows to the other end of the strip through capillary movement to a porous membrane that has two captured antibody zones.
One zone is specific for the GM protein and the other one is specific for untreated antibodies coupled to the reagent (Fig. 10).
The immuno-strips can give results as either ‘Yes’ or ‘No’ within 5 to 10 min. The immuno-strip is an economical, easy and field tractable detection method.
These immuno-strips are commercially available to detect Cry1Ab, Cry1Ac,
Cry2Ab and CP4-EPSPS (Lipton et al., 2000; Fagan et al., 2001).