Using live cells to generate aptamers for cancer study.

Aptamers are ssDNA, RNA, or modified nucleic acids, usually consisting of short strands of oligonucleotides. Aptamers have the ability to bind specifically to a range of targets, from small organic molecules to proteins. However, by using cell-based aptamer selection, we have developed a strategy to identify the molecular signatures on the surface of targeted cells by exploiting the differences at the molecular level between any two given cell types. By applying this method, we have generated a panel of aptamers for the specific recognition of leukemia cells, and we report the results in this study. The selected aptamers were found to bind to target cells with an equilibrium dissociation constant (K (d)) in the nanomolar-to-picomolar range. Overall, the cell-based selection process is simple, fast, straightforward, and reproducible. Most importantly, since this strategy can be implemented without prior knowledge of a target's specific molecular signature, cell-based aptamer selection holds great promise for the development of specific molecular probes for cancer diagnosis and cancer biomarker discovery.