Schematic illustration of DNA aptamer selection by SELEX.

In short, a 200-γ-coated magnetic beads at room temperature for 30 min. Salmon sperm DNA (0.1 mg/mL) and BSA (1 mg/mL) were used to reduce nonspecific binding. After washing, bound ssDNA on magnetic beads were eluted by heating at 95°C for 5 min, and subjected to PCR amplification with fluorescent tag to start the next cycle. After several cycles of selection, the enriched pool of ssDNA was cloned and sequenced for the identification of the individual aptamer.