Screening of oligonucleotide pools. (A, B) AlphaScreen®-based analysis of individual candidates issued from SELEX M1 against a mixed target population a, b and c (A) or from SELEX M2 against the single target × (B). Error bars (horizontal bars in Figure 5 A, B) represent the mean ± SD values of three distinct AlphaScreen® signal measurement for each SELEX population. For M2 the 75 percentile above and below the average is shown. (C) SPR analysis of twelve RNA candidates (corresponding to the red dots in Figure 5A) binding to a premiR target from SELEX M1. 400 RU of the biotinylated target were immobilised on a streptavidin-coated sensor chip (see Methods). The experiments were performed in the SELEX buffer at 23°C and the sensorgrams were collected at a flow rate of 20 μl/min. Candidates were injected at a concentration of 500 nM.