一种用于抗体快速分离的嗜硫纳米粒子的制备及表征

Preparation and Characterization of PEGylated Thiophilic Nanoparticles for Rapid Antibody Separation

以二乙烯基砜为偶联试剂,将聚乙二醇(PEG)固定于氨基硅烷偶联剂改性的磁性纳米粒子上,制备了一种"磁性微核-砜基-聚乙二醇链"的核-壳纳米粒子,兼具砜基的嗜硫作用和PEG的抗非特异性吸附功能。采用~1H NMR和表面Zeta电位分析对制备过程进行了表征。分别以人免疫球蛋白G(人IgG)和牛血清白蛋白(BSA)为抗体和杂蛋白模型,采用静态吸附实验考察了PEG链长、偶联基团、溶液pH值和盐浓度因素对于材料抗体选择性吸附的影响。结果表明,在pH 7.45和0.15 mol/L NaCl溶液条件下,氨基聚乙二醇2000(m PEG2000-NH_2)修饰的磁性纳米粒子具有最优的抗体分离性能,IgG吸附量和选择性分别为132.8 mg/g和32.5(IgG吸附量/BSA吸附量)。在复杂生物样品抗体分离应用中,使用此纳米粒子一步分离可以分别从胎牛血清和无血清细胞培养基中得到纯度为96%的IgG和纯度为99%的奥马珠单抗。此外,采用生物膜层干涉传感技术(Bio-layer interferometer,BLI)对比了此纳米粒子对人、牛、兔和羊的IgG吸附性能的差异,并与传统Protein A配基进行了定量比较。结果表明,此纳米粒子对抗体的吸附具有物种选择性,且与Protein A的物种选择性不同,具有对比Protein A亲和性较差的物种的IgG的快速分离的潜力。

New core-shell structure based magnetic nanoparticles for immunoglobulin separation were prepared,in which thiophilic property of sulfone groups and protein resistance of poly(ethylene glycol)(PEG)moieties were displayed.The step-wise surface reactions on the nanoparticles were characterized by 1H nuclear magnetic resonance(NMR)and surface Zeta potential measurement.With human immunoglobulin G(human IgG)and bovine serum albumin(BSA)as model proteins,the effects of PEG chain length,conjugation group,solution pH and salt concentration on IgG selectivity were investigated using static adsorption experiments.The experiment results showed that mPEG2000-NH 2 modified magnetic nanoparticles had an adsorption capacity of 132.8 mg/g and selectivity of 32.5 towards IgG under the condition of pH 7.45 and 0.15 mol/L NaCl.In complex biochemical solutions,the PEG modified magnetic nanoparticles could separate IgG from fetal calf serum and Omalizumab from cell culture supernatant with purities of 96%and 99%,respectively.Moreover,the binding affinities of the core-shell structure towards IgG from four species(human,bovine,rabbit and goat)were quantified by bio-layer interferometer.The results showed that the selectivity of this structure towards IgG varied from traditional Protein A method,suggesting its potentials in rapid separation and purification of IgG with low affinity towards Protein A.