Fig. 2.
Fluorescence measurements were used to determine dissociation constants (Kd) of the selected aptamer pools after each round of selection. The naïve initial library pool exhibited negligible binding to the PDGF-BB target. After R1, the average Kd of the enriched pool was 57.3 ± 12.0 nM. Subsequently, R2 yielded a pool with an average Kd of 32.1 ± 7.06 nM. Following two sets of negative selection against Tris-coated beads or PDGF-AA-coated beads, R3 positive selection resulted in a pool with an average Kd of 10.5 ± 2.63 nM.