以对苯二甲酸为手臂连接剂的大肠杆菌DNA传感器

Escherichia Coli DNA Biosensor Using Terephthalic Acid as Arm Linker

将空心球状CdS超声分散于聚乙烯醇(PVA)溶液中,得到均匀的CdS-PVA复合材料分散液.取适量分散液滴涂于玻碳电极表面,晾干得到CdS-PVA修饰电极.以对苯二甲酸为手臂连接剂,在CdS-PVA膜上共价固定大肠杆菌特定寡聚核苷酸序列,构建了一种新型的DNA传感器.采用电化学阻抗法考察了该传感器的分析性能,结果表明该传感器能有效区分互补序列、单碱基错配序列、三碱基错配序列和完全错配序列,可在1.0×10-12～1.0×10-7mol/L范围内对大肠杆菌目标序列进行定量分析,检出限为1.3×10-13mol/L.将该传感器应用于大肠杆菌实际样品的检测,结果令人满意.

Ahomogeneous CdSPVA （polyvinyl alcohol） nanocomposite dispersion was obtained by mixing hol low CdS nanospheres in PVA solution under ultrasonic condition. Then the dispersion was dropped on a glassy carbon electrode for dryness to obtain the CdSPVA modified electrode. Further, a novel DNA biosensor for Escherichia coli was fabricated by covalent immobilization of Escherichia coli gene related oligonucleotides on the modified electrode using terephthalic acid as the arm linker. The analytical performance of the biosensor was investigated by electrochemical impedance method, and the results revealed that the constructed biosensor had a wide dynamic range from 1.0xlO12 mol/L to 1. Oxl07 mol/L and a low detection limit of 1.3xlO13 mol/L. The selectivity experiments showed that the DNA biosensor could accurately discriminate the comple mentary sequence from the singlebase mismatched, threebase mismatched and noncomplementay sequences. When the biosensor was applied for the detection of the real sample of Escherichia coli, a satisfying result was obtained.