I3-Cyclodextrinapolyurethane copolymer adsorbent for selective removal of endotoxin from DNA solution

Copolymer particles for removal of endotoxins (lipopolysaccharides, LPSs) were prepared by suspension copolymerization of I3-cyclodextrin (CyD) and 1,6-hexamethylenediisocyanate. The LPS-removing activity of the copolymer particles was compared with that of poly(Im-lysine)-immobilized Cellufine (cationic adsorbent) or polystyrene particles (hydrophobic adsorbent) by a batch method. When DNA was present in solution with LPSs under physiological conditions (pH 6.0, ionic strength of mu = 0.05a0.8), LPS-removing activity of the cationic or hydrophobic adsorbent was unsatisfactory because both the DNA and the LPSs were adsorbed onto each adsorbent. By contrast, the copolymer particles with I3-CyD cavity (CyD content: 14a20 mol%) could selectively remove LPSs from a DNA solution (50 mu g mla1, pH 6.0, and mu = 0.05a0.2) containing LPSs (15 EU mla1) without the adsorption of DNA. The residual concentration of LPSs in the treated DNA solution was below 0.1 EU mla1, and the recovery of DNA was 99%.