基于上转换荧光标记和磁分离技术的沙门氏菌DNA检测新方法

Magnetic Nanoparticles-Based Bioassay for the Detection of Salmonella Using Upconversion Nanoparticles as Labels

DOI：10.3969/j.issn.1673-1689.2013.12.012

中文关键词: 上转换荧光纳米材料 磁性纳米材料 沙门氏菌

英文关键词: upconversion nanoparticles magnetic nanoparticles salmonella bacterium

基金项目:江苏省科技支撑计划项目(BE2011621,BE2012614);中央高校基础研究基金项目(JUSRP11224,JUSRP51309A)

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中文摘要:

利用水热法制备NaYF4:Yb3+Er3+荧光纳米颗粒,表面氨基化修饰后与探针核酸单链共价偶联,形成荧光标记显示探针。再将氨基化的Fe3O4磁性纳米颗粒与捕获核酸单链进行共价偶联,制备磁分离捕获探针。基于DNA杂交互补反应,加入体系中的目标DNA链分别与两端互补的荧光显示探针和磁分离捕获探针形成三明治夹心结构,通过外加磁场收集分离。加入的目标DNA链浓度越大,体系荧光强度越大。结果表明,复合结构的荧光强度与目标DNA链浓度成正比,在0.01~10 pmol/L范围内呈现良好的线性关系,最低检测限达3 fmol/L。

英文摘要:

In this work,a sensitive fluorescent bioassay was developed for the detection of gramnegative bacterium Salmonella specific target DNA sequences. The NaYF4 :Yb3 +Er3 +upconversion nanoparticles(UCNPs) was prepared with high green upconversion fluorescent intensity. The biotinylated Salmonella target DNA complementary sequence 2 was attached to the avidin-conjugated UCNPs and served as the fluorescent signal probe. Then,the as-prepared Fe3 O4 magnetic nanoparticles(MNPs) was first surface modified with avidin molecule,and then combined with the biotinylated Salmonella target DNA complementary sequence 1 which served as the magnetic capture probe. The target DNA could be detected based on the DNA hybridization reaction. The fluorescent intensity was proportional to the concentration of target DNA in the range of 0.01 pmol/L to 10 pmol/L with detection limit as low as 3 fmol/L. The presented upconversion fluorescent method is simple,fast,sensitive,specific,and furthermore,it offers another great promise for the application of nanomaterials in biosensor design.

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