Multi-Parameter Particle Display (MPPD): A Quantitative Screening Method for Discovery of Highly Specific Aptamers

摘要

Aptamers are a promising class of affinity reagents because they are chemically synthesized, making them highly reproducible and distributable as sequence information rather than a physical entity. Although many high-quality aptamers have been previously reported, it is difficult to routinely generate aptamers that possess both high affinity and specificity. One of the reasons is because conventional aptamer selection can only be performed either for affinity (positive selection) or for specificity (negative selection), but not both simultaneously. In this work, we harness the ability of fluorescence activated cell sorting (FACS) to perform multi-color sorting to simultaneously screen for affinity and specificity at a throughput of 10⁷ aptamers per hour. As proof of principle, we generated DNA aptamers for three diverse proteins that exhibit picomolar to low nanomolar affinity in human serum, and show that these aptamers are capable of outperforming high-quality monoclonal antibodies in a standard ELISA detection assay.