Selective removal of endotoxin from a DNA solution by cross-linked cyclodextrin beads.

The removal of lipopolysaccharide (LPS) from a contaminated DNA solution was achieved using cross-linked cyclodextrin (CyD polymer) beads as LPS adsorbents. The LPS-removing activity of the β- and γ-CyD polymer beads was compared with that of common cationic LPS adsorbents. The γ-CyD polymer beads selectively removed LPS from a DNA solution (50 μg mL−1, pH 6, ionic strength μ = 0.2) containing natural LPS (15 EU mL−1), without the adsorption of DNA. The adsorptions of LPS and DNA were 85% and <1%, respectively.