中文摘要：

目的：基于Au/SiO2信号放大,通过循环伏安法实现对沙门氏菌（Salmonella）的高灵敏度检测.方法：将与沙门氏菌靶基因DNA互补配对的碱基序列（捕捉DNA和显示DNA）,分别修饰于导电玻璃电极（indium tin oxide,ITO）及Au/SiO2纳米颗粒表面,构建捕获探针和显示探针,当在体系中加入沙门氏菌靶DNA后,会形成捕捉DNA-靶DNA-显示DNA构成的“三明治夹心”结构.由于Au/SiO2的含量与靶DNA浓度呈正相关,因此靶DNA浓度的变化可导致ITO峰电流值相应变化,从而达到检测目的.结果：在最优实验条件下,检测沙门氏菌靶DNA时,浓度在10-11～10-7 mol/L范围内呈现出良好的线性关系,线性回归方程为y=-0.000 3x＋0.000 1（R2=0.998 9）,最低检测限为6 pmol/L;检测沙门氏菌时,线性范围为50～7 910 CFU/mL,线性回归方程为y=-1.6×10-7x＋0.003 2（R2=0.994 0）,最低检测限为35 CFU/mL.结论：经特异性及实验加标回收实验证明本方法可用于实际样品的检测.

英文摘要：

Purpose：To establish a detection method with high sensitivity for Salmonella by cyclic voltammetry based on Au/SiO2 signal amplification.Methods：The capture DNA and the display DNA,which are complementary with the target DNA were modified onto the surface of indium tin oxide （ITO） electrode and the surface of Au/SiO2 nanoparticles.As results,capture probe and display probe were constructed.A ＂sandwich＂ structure was constructed by capture DNA-target DNA-display DNA when Salmonella target DNA was added into the system.As the content of Au/SiO2 was positively correlated with the concentration of the target DNA,the peak current value of fully modified ITO could be changed by varying the concentration of the target DNA,so as to achieve the purpose of detection.Results：Under the optimal conditions,the method showed a good linear relationship when the concentration of target DNA was in the range of 10-11 to 10-7 mol/L,the linear regression equation was y =-0.000 3x ＋ 0.000 1 （R2 =0.998 9）,and the lowest limit of detection （LOD） was 6 pmol/L.And it showed a good linear relationship when the concentration of Salmonella was in the range of 50 to 7 910 CFU/mL,the linear regression equation was y =-1.6 × 107x ＋ 0.003 2 （R2 =0.994 0）,and the lowest LOD was 35 CFU/mL.Conclusions：The specificity and spiked recovery experiments proved that this method could be used for the detection of actual samples.