由病原微生物引起的食源性疾病日益引起全球关注，迫切需要开发同时快速检测多种食源性致病菌的方法。本研究建立了一种基于磁性适配体捕获探针的微流控芯片-比色双模式传感器，实现了副溶血性弧菌（V.P）和鼠伤寒沙门氏菌（S.T）的快速定性和同时定量分析。此探针包括磁珠及其表面修饰的含ATP、待测物适配体及重复G碱基核苷酸片段的DNA长链。当探针和目标物结合后，会释放出上述DNA长链，形成与氯高铁血红素（Hemin）结合的G四链体，具有类过氧化物酶活性，可催化四甲基联苯胺（TMB）-H₂O₂体系的反应，产生肉眼可见的蓝色，实现两种致病菌的现场分析。释放的DNA长链经过EcoRV核酸内切酶剪切后，得到不同长度DNA片段，分别对应V.P和S.T的数量。在微流控芯片中分析和测定各片段，可实现两种细菌的定量分析。在最佳实验条件下，传感器对两种细菌检测的线性范围为10²~10⁷ CFU/mL，检出限可达30 CFU/mL。此传感器为现场定性筛查致病菌污染水平和实验室准确检测其含量提供了可靠的方法。

Foodborne diseases caused by pathogenic microorganisms have attracted increasing attention in the world. It is urgent to develop efficient analytical methods for simultaneous and rapid detection of foodborne pathogens. In this regard, a dual-mode sensor based on the colorimetric principle coupled with microfluidic chip was developed using magnetic aptamer capture probes. It could realize rapid qualitative and simultaneous quantitative determination of Vibrio parahaemolyticus (V.P) and Salmonella typhimurium (S.T). The probe consisted several long DNA strands containing adenosine triphosphate (ATP), analyte aptamer and repeated G-base nucleotide fragments which were labeled on the surface of magnetic beads. When the probe reacted with the target analytes, the above long DNA strands would be released. The G quadruplet formed by hemin exhibited catalytic effect on tetramethylbenzidine (TMB)-H₂O₂ system, which could produce visible blue color and be used for on-site analysis of two pathogenic bacteria. After the long strand of released DNA was cut by EcoRV endonuclease, different lengths of DNA were obtained corresponding to V.P and S.T respectively. By analyzing each DNA in microchips, quantitative analysis of two kinds of bacteria V.P and S.T could be realized. Under the best experimental conditions, the detection linear range for the two bacteria was 10²-10⁷ CFU/mL, and the detection limit was 30 CFU/mL. The sensor provided a reliable method for screening contamination of pathogenic bacteria and quantification of each target accurately in the laboratory.