Binding measurements in CE.

(a) Electropherogram of A9 binding to the purified H9-HA. The purified HA was detected by a UV detector (280 nm) and had a migration time of 5.4 min. A₁, A₂, and A₃ represent the areas of peaks of the complexes (A₁), the aptamer dissociated from the complex during electrophoretic separation (A₂) and the free aptamer (A₃) respectively. (b) CE detection of the aptamer-virus interaction. The purified H9N2 AIV was detected by a UV detector (280 nm) and had a peak at the migration time of 7.4 min. The arrows showed the aptamer-virus complex at the migration time of 9.1 min. LIF detector was used for all FAM labeled aptamers. K_d values were determined with a previously developed CE-based method (see reference [32]).