λ-DNA通过纳米通道产生电流信号的1/f噪声分析

1/f noise analysis of current signals generated by λ-DNA translocation through nanochannel

利用膜片钳采集了λ-DNA通过纳米通道时的电流信号,分析了电压、通道几何形状与尺寸、盐浓度以及通道材料等因素对信号1/f噪声的影响.研究结果表明,纳米通道内的1/f噪声是由溶液体态离子与壁面电荷综合作用引起的.对于氮化硅纳米通道,当电压绝对值增大至一定程度时,通道内部会出现电荷局部拥挤现象,导致局部电阻增大,1/f噪声的功率也随之增大.孔径对氮化硅纳米通道检测信号的1/f噪声影响相对较小.石墨烯的结构电容大并具有极高的载流子迁移率,故其噪声信号明显强于氮化硅纳米通道.研究结果有助于辨识λ-DNA通过纳米通道时产生的高信噪比电流信号.

The current signals generated by λ-DNA translocation through nanochannels were collected by using the patch clamp.The influences of voltage,channel geometry shape and size,salt concentration and channel materials on the 1/f noise w ere analyzed.The results show that the 1/f noise in nanochannel is caused by the comprehensive action of the ions in the solution and the surface charge of the nanochannel.As for the silicon nitride（SiN） nanochannel,a charge local congestion phenomenon occurs in the nanochannel w hen the absolute value of the voltage is increased to some extent,inducing the increase of the local resistance and the pow er of 1/f noise.The diameter of SiN nanochannel has little effect on the 1/f noise of the detected ionic signals.Compared w ith the SiN nanochannel,the grapheme nanochannel has larger noise because of its bigger structure of capacitance and higher carrier mobility.The results can help to identify the current signals w ith high signalto-noise ratio generated by λ-DNA translocation through nanochannels.