Dynamic selection of high-affinity aptamers using a magnetically activated continuous deflection microfluidic chip.

To accelerate the discovery of high-affinity aptamers, a magnetically activated continuous deflection (MACD) chip was designed. The MACD chip could achieve dynamic selection in a continuous flow, which meant that the binding and separation were carried out consecutively. Dynamic selection could make selection efficient. Low-affinity sequences could be eluted in time and high-affinity sequences could be enriched via dynamic selection. The stringency of the conditions could be further increased by lowering the target concentration in the dynamic selection. Finally, a C.al3 aptamer with high-affinity and high-specificity for Candida albicans ( C. albicans ) was obtained through six rounds of selection. Its dissociation constant ( K d ) was 7.9 nM. This demonstrated that dynamic selection using a MACD chip was an effective method for high-affinity aptamer selection.