γ-Cyclodextrin/polyurethane Copolymer Adsorbent for Selective Removal of Endotoxin from DNA Solution

Abstract

Copolymer particles for removal of endotoxins (lipopolysaccharides; LPS) were prepared by suspension copolymerization of γ-cyclodextrin (CyD) and 1, 6-hexamethylenediisocyanate. The LPS-removing activity of the copolymer particles was compared with that of poly (ε-lysine) -Cellufine (cationic adsorbent) by a batch method. LPS-removing activity of the cationic adsorbent was unsatisfactory because both the DNA and the LPS were adsorbed at pH 6.0, ionic strength of μ=0.05-0.8. In contrast, the copolymer particles with γ-CyD cavity (CyD content: 14–20 mol%) could selectively remove LPS from a DNA solution (50 μg/ml, pH 6.0 and μ=0.05–0.2) containing LPS (15 EU/ml). The residual concentration of LPS in the treated DNA solution was below 0.1 EU/ml, and the recovery of DNA was 99%.