Based on the electrochemiluminescence and magnetic suspension immunoassay strategy, a new magnetic graphene and paper-based screen-printed electrode ( SPE ) electrochemiluminescence sandwich immunoassay was developed by combination of the unique physical and chemical properties of magnetic graphene and the advantages such as low cost and low-volume sample consumption of paper-based SPE. Taking human IgG as the model analyte, EDC/NHS method was used to couple capture antibody ( Ab1 ) and magnetic graphene, and direct labeling method was used to label signal antibody ( Ab2 ) with Ru NHS ester. Nonspecific adsorption was highly reduced by the magnetic suspension sandwich immunoassay strategy, and the concentration information of the analyte was obtained by paper-electrochemiluminescence detection. Experimental study of immobilization and labeling effect of Ab1 and Ab2 showed that the magnetic graphene not only improved the load of immune substances, but also promoted the electron transfer. The developed magnetic suspension and paper-based electrochemiluminescence immunoassay could realize the quantitative detection of IgG and had certain application prospect in low cost and rapid immune detection field.%基于电化学发光及磁悬浮免疫分析策略,结合磁性石墨烯独特的物理化学特性以及纸基电极价格低廉、样品用量少的优势,建立了一种新型免疫分析方法.以人免疫球蛋白G(IgG)为分析物,采用1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺/N-羟基硫代琥珀酰亚胺(EDC/NHS)法将一抗(Ab1,捕获抗体)固定在磁性石墨烯上,通过直接标记法进行二抗(Ab2,信号抗体)的电化学发光试剂标记,采用磁悬浮夹心免疫技术最大程度减少非特异性吸附,通过纸基电化学发光检测技术测定目标物的浓度.考察了捕获抗体及信号抗体的固定(标记)效果,发现采用的磁性石墨烯不仅提高了免疫物质的负载量,还可以促进电子传递,构建的磁悬浮纸基电化学发光夹心免疫分析法的电化学发光响应峰面积在0.32~1000 ng/mL浓度范围内,与IgG浓度对数值呈良好的线性关系,检出限为6.4 pg/mL.本方法可实现IgG的定量检测,在低成本、快速免疫检测领域有一定的应用前景.
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