Synthesis Of Novel Endotoxin Adsorbent And Study Of Adsorption Capability

Endotoxin, represented lipopolysaccharides chemically, is an integral part of the outer cellular membrane of gram-negative bacteria. Endotoxin plays a pivotal role in sepsis and septic shock syndromes associated with serious Gram-negative infections. Removal of endotoxin duly from plasma of patient by adsorbents of blood purification is effectual in endotoxemia treatment in clinic. In order to improve the adsorption capacity for endotoxin in human plasma, Agarose 4FF gel is selected as matrix to prepare adsorbents, on which twelve functional groups are immobilized based on the structure of endotoxin molecule by hydrogen bonds, electrostatic forces and hydrophobic interaction. The conditions of synthesis of adsorbent are optimized and the adsorption characteristics are researched as well. Factors of effect on endotoxin adsorption in human plasma are also investigated. Experimental results show:(1) Among twelve functional molecules, 2, 3-epoxypropyltrimethylammonium chloride (EPTMAC) mainly to the electrostatic interaction, sulfamethoxypyridazine (SMPD) and cephalin mainly to the hydrophobic interation have stronger interacton with endotoxin.(2) The Agarose 4FF gel, actived with allyl bromide, coupled the branch ligand containing two different functional molecules, EPTMAC and SMPD; represent most excellent adsorption capacity for endotoxin. The denser the functional groups, the higher the adsorption capacity. With the increase of functional chains' length, the adsorption capacity increases slightly. The adsorption isotherms of endotoxin and human serum albumin show the adsorbent, coupled the branch ligand containing two functional molecules, EPTMAC and SMPD, have higher selectivity of endotoxin adsorption than that of single EPTMAC or SMPD ligand.(3) The adsorption capacity increases obviously with the rise of initial endotoxin concentration. The removal rate of endotoxin has positive correlation with the ratio of adsorbent to plasma. The equilibrium of adsorption can be reached within 0.5 hours. With the initial endotoxin concentration is 5.08 EU/mL, the ratio of adsorbent to plasma is 1:5, the removal percentage of endotoxin reached 56.31% and total protein lost only 6.57 %.