Synthesis And Application Of Low Density Lipoprotein Cholesterol Adsorption Medium

Atherosclerosis is usually be treated by two methods,which is called in vivo and in vitro treatment.For in vitro treatment,adsorbents are used to adsorb excessive amounts of low-density lipoprotein cholesterol(LDL)in blood,an index of atherosclerosis,to cure the disease.In this study,a new type of amphiphilic adsorbent containing both hydrophobic and hydrophilic groups at the surface was developed.Based on previous studies,we prepared the new absorbents using macroporous resin modified with affinity adsorption groups.The S-8 macroporous resin composed of hydroxylated polystyrene-divinyl benzene was modified with the hydrophobic group amino acid,and then grafted with hydrophilic sulfonic acid groups.The static and dynamic adsorption of this amphiphilic adsorbent were evaluated.Futhermore,a preliminary study on its hemo-compatibility was carried out.The main conclusions are as the follows:(1)Due to the similarity in the structure of sodium lignosulfonate with heparin which is a good at adsorbing LDL,we tried to graft sodium lignosulfonate to the macroporous resin instead of heparin.However,the adsorption experiments showed that the LDL adsorption selectivity is very poor with high adsorption of blood beneficial component such as high density lipoprotein cholesterol(HDL).The static adsorption efficiency of LDL and HDL is around 40%and 19%,respectively.(2)Amphiphilic adsorbent was prepared using S-8macroporousresin grafted with lauric acid and then sulfonated using acetyl sulfonate.The static adsorption efficiency of LDL and HDL were 57%and 11%,respectively.(3)A new type of amphiphilic adsorbent based on S-8 macroporous resin modified with hydrophobic amino acid and acetylsulfonate was further developed.The static adsorption efficiency for LDL and HDL is around 50%and about 5%,respectively.S-8macroporous resin grafted by peptides composed of three hydrophobic amino acid and sulfonated was produced.The static adsorption efficiency of LDL and HDL is around 89%and 59%,respectively.(4)The dynamic adsorption performance of the amphiphilic adsorbent based on S-8 macroporous resin modified with hydrophobic amino acid and sulfonation was evaluated at the different flow rates,600,1800 and 4200 cm/h.The adsorption efficiency of LDL gradually decreases with the increasing plasma flow rate while the adsorption efficiency of HDL increases gradually.At the flow rate of 600cm/h which is used under clinical condition,the adsorption efficiency of LDL and HDL is around 69%and 12%,respectively.(5)A preliminary study on hemo-compatibility of this new type absorbent was performed.The hemolysis rate is less than 5%.The prothrombin and thrombin time is longer than the initial value,but within the normal limit.All these experimental results indicates that the adsorbent has good anticoagulant performance without seeing a large number of blood platelets on the surface.