Direct detection of the hybridization of synthetic homo-oligomer DNA sequences by field effect
Direct detection of the hybridization of synthetic homo-oligomer DNA sequences by field effect
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DOI：
10.1021/jp963056h
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发表时间：
1997-04-10
影响因子：
3.3
通讯作者：
Lawrence, MF
中科院分区：
文献类型：
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作者：
Souteyrand, E;Cloarec, JP;Lawrence, MF
使用3-氨丙基三乙氧基硅烷将均聚物DNA链固定到硅/二氧化硅电极上。将这些改性的基底用作三电极电化学电池中的工作电极。在Ag/AgCl参比电极的-1至+1 V范围内测量同相和异相阻抗，叠加10 mV交流信号，频率为20和100 kHz。在修饰电极的表面处进行的与互补低聚物链的非原位杂交清楚地反映在半导体的平带电位中约100 mV的负位移。连续的杂交-变性步骤表明，位移是可重复的，该过程是可逆的。互补链的原位杂交也已观察到在Si/SiO2基板的阻抗测量和使用的场效应装置。在恒定漏极电流模式下，用场效应器件直接检测杂交，观察到的杂交过程中栅电位的相应变化与阻抗实验观察到的平带电位漂移非常一致。在非互补链存在下进行的测量证明了该装置的选择性。
Homo-oligomer DNA strands were immobilized onto silicon/silicon dioxide electrodes using 3-aminopropyltriethoxysilane. These modified substrates were used as working electrodes in a three-electrode electrochemical cell. In-phase and out-of-phase impedances were measured in the range -1 to +1 V with respect to an Ag/AgCl reference electrode, with a superimposed 10 mV ac signal at frequencies of 20 and 100 kHz. Ex situ hybridization with complementary oligomer strands, performed at the surface of modified electrodes, is clearly reflected by negative shifts of about 100 mV in the flat-band potential of the semiconductor. Consecutive hybridization-denaturation steps show that the shifts are reproducible and the process is reversible. The in situ hybridization of complementary strands has also been observed with impedance measurements at Si/SiO2 substrates and with the use of a field effect device. The direct detection of hybridization with a field effect device was performed under constant drain current mode, and the corresponding variations observed for the gate potential during hybridization are in good agreement with the flat band potential shifts observed with the impedance experiments. Measurements made in the presence of noncomplementary strands demonstrate the selectivity of the device.