基于金纳米棒金属化的呕吐毒素多色可视化检测方法研究

目的 基于免疫亲和反应和酶诱导金纳米棒金属化构建一种呕吐毒素多色可视化检测方法。方法 将表面修饰高亲和性抗体的免疫磁珠作为信号转移载体,将金纳米棒作为多色反应基底,样品中的呕吐毒素与生物素修饰的呕吐毒素抗原竞争结合磁珠表面的抗体上,进一步基于生物素和链霉亲和素的特异性亲和反应,链霉亲和素标记的碱性磷酸酶被结合到免疫磁珠上,并催化底物L-抗坏血酸-2-磷酸三钠盐生成抗坏血酸,随后还原硝酸银生成银单质包被在金纳米棒表面。该过程使金纳米棒的纵向等离子体吸收峰发生蓝移,同时产生裸眼可见的丰富颜色变化。可实现不同浓度下呕吐毒素的多色可视化检测。结果 在最佳反应条件下,检测呕吐毒素的线性范围是0～1000ng/mL,检出限为264.71ng/mL,对小麦和玉米质控样品的检测结果回收率在88.7%～107.4%之间,相对标准偏差小于等于14.1%。结论 该方法检测结果直观、灵敏度较高、操作便捷,无需步骤复杂的人工操作,检测过程用时较短,可用于粮食中呕吐毒素的可视化检测。

Multicolor visual detection of deoxynivalenol based on metallization of gold nanorods

Objective To establish a multicolor visual method for deoxynivalenol detection based on immunoaffinity reaction and enzyme-induced metallization of gold nanorods. Methods The immunomagnetic bead modified with high affinity antibody was used as the signal transfer carrier, and the gold nanorods were used as multicolor reaction substrate. The deoxynivalenol in the sample and the biotin-modified deoxynivalenol antigen were successively bound to the magnetic beads. After specific affinity reaction of biotin and streptavidin, alkaline phosphatase is bound to immunomagnetic beads and catalyze the substrate L-ascorbic acid-2-phosphate trisodium salt to produce ascorbic acid. Subsequently, silver nitrate was reduced to silver element and coated on the surface of gold nanorods. This process results in a blue shift of the longitudinal plasma absorption peak of the gold nanorods and a rich color change visible to the naked eye. The buffer solution pH, substrate concentration, silver nitrate concentration and catalytic reaction time were optimized. Results Under the optimal reaction conditions, the linear range of deoxynivalenol was 0-1000 ng/mL, and the detection limit was 263.16 ng/mL. The recovery rate of wheat and corn quality control samples was 101.3% -110.5 %, and the relative standard deviation was less than 14.1 %. Conclusions This method has the advantages of intuitive detection results, high sensitivity,convenient operation, no complicated manual operation, and short detection time, which can be used for visual detection of deoxynivalenol in grain.