铂纳米颗粒修饰电化学DNA传感器检测大豆中转基因成分

Electrodeposited Pt-Nanoparticles DNA Biosensor for the Detection of Specific Deoxyribonucleic Acid in Genetically Modified Soybean

用电沉积方法将铂纳米颗粒修饰在玻碳电极表面,然后将花椰菜花叶病毒35S启动子ssDNA片段直接吸附在铂纳米颗粒上,制成特异的电化学DNA传感器。用扫描电子显微镜和循环伏安法对修饰铂纳米颗粒电极进行了表征。ssDNA探针与互补目的ssDNA杂交,以[Co(phen)3]3+(phen=1,10-Phe-nanthroline)为杂交指示剂,用方波伏安法进行检测,表现出良好的响应信号。与在裸玻碳电极上修饰的探针相比,测定目的基因的灵敏度显著提高。传感器对互补目的ssDNA检测的线性范围为2.14×10-9～2.14×10-7mol/L;检出限为1.0×10-9mol/L,与3个碱基错配的DNA序列杂交,观察不到明显的杂交信号。样品DNA经HindⅢ非限制性内切酶酶切后测定,杂交检测信号增大。用传感器检测含量不同的转基因大豆DNA和非转基因大豆DNA的混合溶液,杂交前后的电流差与转基因DNA的含量呈良好线性关系。连续5次测量含有100%转基因大豆DNA杂交后的电信号,相对标准偏差为5.89%,固定探针的电极再生后可重复使用8次。

DNA biosensors were prepared using platinum nanoparticles（Pt-nano） that were electrodeposited on the surface of a glassy carbon electrode（GCE）.A 19-mer ssDNA of promoter 35S that was specific for most inserted sequences in genetically modified food was immobilized on the Pt nanoparticle-deposited GC electrode（Pt-nano/GCE）.The morphology of the surface of Pt-nano/GCE was investigated with a scanning electron microscopy.The electrochemical response of the sensor to the complementary DNA was studied using ／[Co（phen）3／]^3＋ ion（phen=1,10-phenanthroline） as an electrochemical indicator.The response of Pt-nano/GCE was significantly higher as compared with that prepared based on a bare GC electrode of same geometric surface area.A linear calibration graph for the complementary DNA over the concentration of 2.14×10^-9-2.14×10^-7 mol/L was obtained and the limit of detection was 1.0×10^-9 mol/L,while almost no response was observed for the three-base-mismatched DNA.The detection response of the digested sample DNA by unrestricted endonuclease（HindⅢ） was higher than that of the undigested sample DNA.When the DNA sensors were used for the determination of the concentration of the DNA sequence extracted from the genetically modified soybean sample,the results were satisfactory.The relative standard deviation was 5.89% for extracted sample DNA（n=5）.The DNA sensor can be regenerated and used 8 times without deterioration.