Ion-exchange chromatography is widely used for purification and separation of biomolecules. Traditionally, charged ligands are introduced into ion-exchange matrices by random chemical processes, producing a heterogeneous charge distribution. In previous work, we demonstrated improved selectivity and affinity of adsorbents in which charges are introduced in a clustered, rather than random fashion.
The current work establishes the enhanced DNA adsorption affinity and capacity of clustered pentaargininamide vs. equal-charge argininamide adsorbents. The effects of ligand density are explored, as well as mechanisms of maximizing DNA selectivity over RNA. Early results on the single-molecule monitoring of biomolecule adsorption in realistic agarose adsorbents also will be presented.