SECM的产生收集模式检测小鼠免疫球蛋白IgG

Detection of mouse IgG by generation/collection mode of SECM

基于扫描电化学显微镜(SECM)产生收集模式,开展小鼠免疫球蛋白IgG(作为抗原)检测研究.利用分子自组装的方式,以硫辛酸为媒介,利用金与硫的键合作用以及羧基与氨基的化学反应将羊抗鼠抗体修饰在金电极上,辣根过氧化氢酶(HRP)标记的小鼠抗原与未标记的小鼠抗原再通过竞争与有限的抗体位点结合,完成小鼠抗原检测平台的搭建.HRP与过氧化氢(H2O2)的催化反应使得对苯二酚(H2Q)被氧化为对苯醌(BQ),BQ在探针上被还原.利用逼近曲线,通过记录加入不同浓度比的小鼠抗原混合液时探针上还原电流的变化来进行待测物(小鼠抗原)的检测,结果表明,小鼠免疫球蛋白IgG在1~1000pg·mL^-1浓度范围内,探针电流与浓度的变化呈线性关系,检测限为0.1pg·mL^-1.

Scanning electrochemical microscopy(SECM)with immunological reaction was applied to detect the mouse IgG.In the way of molecular self-assembly,using lipoic acid as the medium,goat anti-mouse antibody was modified on the gold electrode by the bond between gold and sulfur and the chemical reaction of carboxyl group and amine group.The assay involved a competitive mode between HRP labeled mouse IgG and unlabeled mouse IgG and both antigens were captured by antibodies immobilized on the surface of gold substrate.The establishment of mouse antigen detection platform was completed.Interrogation of the modified substrate by SECM approach curve of substrate generation/tip collection mode was carried out after the catalytic reaction between HRP and H2O2 which resulted in the oxidation of H2Q to BQ,then BQ was reduced on the probe.The approach curve was used to detect the mouse antigen through the change of reducing current on the probe.This change was caused by the different concentration ratio between labeled and unlabeled mouse IgG in the mixture solution.The results showed that there was a linear relationship between the probe and concentration of mouse IgG in the range of 1-1000 pg·mL^-1,and the detection limit was as low as 0.1 pg·mL^-1.