Effects of amino-group content and hydrophobicity of cross-linked N,N-dimethylaminopropylacrylamide adsorbents on selective removal of lipopolysaccharide

Cross-linked N,N-dimethylaminopropylacrylamide (DMP) spherical particles fo r the selective removal of lipopoly-saccharides (LPS) from protein solution were prepared. When N, N'-buthylene-bis-methacrylamide (BBMA) and divinylb enzene (DVB) were each used as a cross-linking agent and the amino-group co ntent was adjusted to 4.0 meg g(-1) adsorbent or more, the DMP/BBMA and the DMP/DVB adsorbents showed good LPS adsorption at pH 7.0 and an ionic stren gth of mu = 0.05 to 0.2. On the other hand, the adsorption of bovine serum albumin, an acidic protein, by each adsorbent increased with the increase i n the amino-group content to 4.5 mequiv. g(-1) adsorbent or larger, but dec reased with the increase in the ionic strength (mu) of the buffer to 0.2 or stronger. Only DMP/DVB specifically adsorbed aromatic proteins such as cyt ochrome c and myoglobin, over a wide ionic strength range of mu = 0.05 to 1 .0. As a result, when the DMP/BBMA adsorbent which had an amino-group conte nt of 4.0 meg gl was used in conditions of pH 7.0 and mu = 0.05, LPS was se lectively removed from various protein solutions, naturally contaminated wi th LPS.