FIG. 4.

Saturation binding of selected aptamer clones on immobilized bio-ABA. Binding of clone 2 and of clone 9 to bio-ABA was assessed by enzyme-linked oligonucleotide assay (ELONA), as described under Materials and Methods. A fixed concentration (6 μM) of bio-ABA immobilized on streptavidin-coated magnetic beads was incubated with increasing concentrations (0.1–8 μM) of digoxigenin-labeled aptamers. Anti-digoxigenin-HRP antibodies were then added and revealed with ABTS® solution at 405 nm. All experiments were performed in triplicate and each point is the average of three determinations. R² values were 0.9997 for clone 2 and 0.9999 for clone 9.