Extraction of Lipopolysaccaride Using Thermoresponsive Polymer

聚N-异丙基丙烯酰胺(PNIPAAm)是一种水溶性聚合物，在较低的临界溶液温度(约32℃)以上变得不溶于水，形成体积分数很小的胶状聚集体(聚合物相)。具有疏水性脂类部分和亲水性多糖的脂多糖的萃取率低于脂类，但可以很好地浓缩到少量聚集的聚合物沉淀物(聚合物相)。相比之下，包括糖、尿素、肌酸、血清蛋白和无机离子在内的亲水性化合物几乎不能进入聚合物相。通过LPS的PNIPAAm水溶液，可以将校正后的LPS回收到KURIMOVER(壳聚糖珠)柱上。聚合物介导法的应用将极大地拓展该方法在痕量LPS预浓缩中的应用潜力。

A water-soluble polymer, poly(N-isopropylacrylamide), PNIPAAm, become waterinsoluble above a lower critical solution temperature(ca.32℃)and forms gum-like aggregates(polymer phase) having very small volume fraction.Lipopolysaccharide(LPS) was successfully extracted by polymer-mediated extraction based on the thermoresponsive precipitation of water-soluble polymer PNIPAAm in aqueous solutions. LPS having hydrophobic lipid moiety and hydrophilic polysaccharides was less extractive than lipids but well concentrated to small volume of aggregated polymer precipitates (polymer phase). In contrast, hydrophilic compounds including saccharides, urea, creatine, serum proteins and inorganic ions hardly incorporated into the polymer phase. Corrected LPS could be recovered to KURIMOVER(chitosan beads) column by passing though the aqueous PNIPAAm solution of LPS.The application of the polymer-mediated extraction will greatly extend the potential of this method in the pre-concentration of traces of LPS.