还原氧化石墨烯/纳米金非酶标记免疫传感器检测单核细胞增生李斯特氏菌

Detection of Listeria monocytogenes using reduced graphene oxide/AuNPs nanocomposites as non-enzymatic immunosensor

为构建用于快速检测单核细胞增生李斯特菌(L.monocytogenes)的非酶标记免疫传感器,本研究以还原氧化石墨烯为基板固定的Au NPs作为电化学标记,以免疫磁性纳米微球(IMNPS)为捕获探针。以修饰单核细胞增生李斯特菌抗体(Anti-L.monocytogenes)的还原氧化石墨烯/纳米金(r GO/Au NPs)作为非酶标记物与富集L.monocytogenes的IMNPS形成夹心结构,在外加磁场的作用下将夹心结构复合物吸附在丝网印刷碳电极(SPCE)表面,采用差分脉冲伏安法进行分析。该免疫传感器检测L.monocytogenes的DPV响应信号在10~3 cfu/m L^10~9 cfu/mL具有良好的线性关系,线性回归方程为y=0.02933x-0.01996,R^2=0.99367,检出限为1.8×10~4 cfu/mL(S/N=3),即在检测3μL的检测样品中54 cfu的L.monocytogenes即可被检出。本研究所制备的电化学免疫传感器,成本低,操作简便,在实际应用中具有良好的前景。

In order to construct a non-enzyme immunosensor for detecting Listeria monocytogenes. In this method, the gold nanoparticle （AuNPs） were immobilized on the substrate of reduced graphene oxide （rGO） as an electrochemical label, and the immunomagnetic nanoparticles （IMNPS） were used as the capture probe. The sandwich structures were formed between IMNPS and antibody-modified rGO/AuNPs. Under the effect of the external magnetic field, the sandwich structure was absorbed on the surface of the screen printed carbon electrode （SPCE）. The differential pulse voltammetry （DPV） was used to obtain the response signal. DPV response signal of the immunosensor had alinear relationship range from 103 to 109 cfu/mL of L.monocytogenes, the linear regression equation was y=0.02933x-0.01996 with a regression coefficients of 0.99367. The limit of detection （LOD） was 1.8×10^4 cfu/mL （S/N=3）, which was equivalent to 54 cfu of L.monocytogenes in 3 μL samples. The electrochemical immunosensor has the advantages of low cost, easy operation and good prospect in practical application.