DNA与羧化PS纳米小球在外加电压下通过微纳通道的电流特性研究
发布时间：2019-02-19 14:23
【摘要】：在微纳芯片和生物传感器的实际应用中,利用微流体通道电场力驱动操作并分析单个生物大分子的特性,可以准确、灵活地实现对单分子的控制。本文基于三电极体系,系统地研究了电场力驱动下DNA及PS纳米小球穿越微纳通道(内径10 μm,5 μm,500 nm,200nm,100 nm)时的特征电流信号。研究发现微纳通道尺寸、溶液pH以及缓冲液浓度都会影响微纳流的电流响应信号,并且出现临界电压的现象。这些对于微流控技术与设备的改进以及信噪比的提高有着重要的意义。本文的主要内容及结论包含以下几个方面:(1)实验发现,不同尺寸通道均有相同的电流现象,即:初始电流响应有瞬态上升值与瞬态下降值,而后随时间改变最终趋于稳定。理论分析认为是电极极化以及双电层影响下的电渗流共同作用的结果。(2)研究了 DNA分子/PS纳米小球溶液在微/纳通道的电流信号。当通道内只加入纯的TBE溶液时,电导并不是随通道直径减小而单调递减,而是在亚微米尺度随通道直径的减小而增加。实验观察到200 nm通道在外加电压20 mV时的电导瞬态下降现象。当DNA分子或PS纳米粒子加入时,通道尺寸效应引起的电导规律也不同。(3)通过对加入λ-DNA和羧化PS纳米小球在不同尺寸的通道、不同偏置电压、缓冲液浓度、pH等的电流响应进行研究,利用表面电荷、电渗流及双电层的有关理论分析了上述条件对电流信号影响的机理:发现临界电压随着缓冲液pH、通道尺寸的增大而减小,随缓冲液浓度的增加而增大。pH对信噪比的影响:pH越大,信噪比越低。(4)在100nm通道中,随着pH的增加,稳定电流I也随之增大。临界电压随着pH的增加而减小;随着缓冲液浓度的增加,临界电压反而越小。在外加电压小于临界电压Uc时,随着电压增加,稳定电流绝对值反而减小。通过对电流响应信号与临界电压的分析,进而探讨DNA、PS纳米小球在通道中的运动特性,有助于研制具有特殊功能的微/纳米通道流体传感器和生物芯片。
[Abstract]:In the practical application of micronano chip and biosensor, the control of single molecule can be realized accurately and flexibly by using the microfluid channel electric force driving operation and analyzing the characteristics of a single biological macromolecule. Based on the three-electrode system, the characteristic current signals of DNA and PS nanospheres traversing micro-nano channels (10 渭 m ~ 5 渭 m ~ (500 nm,200nm,100 nm) in diameter) driven by electric field force are studied systematically in this paper. It is found that the size of the microchannel, the solution pH and the buffer concentration all affect the current response signal of the micronano flow and the phenomenon of critical voltage appears. These are of great significance for the improvement of microfluidic technology and equipment and the improvement of signal-to-noise ratio (SNR). The main contents and conclusions of this paper include the following aspects: (1) the experimental results show that there are the same current phenomena in the channels of different sizes, that is, the initial current response has transient upward appreciation and transient decline. Then it changes over time and eventually stabilizes. Theoretical analysis shows that this is the result of electrode polarization and electroosmotic interaction under the influence of double layer. (2) the current signal of DNA molecule / PS nanoparticles solution in microchannel / nanowires is studied. When only pure TBE solution is added into the channel, the conductance does not decrease monotonously with the decrease of channel diameter, but increases with the decrease of channel diameter at sub-micron scale. The transient decrease of conductance of 200 nm channel was observed at applied voltage of 20 mV. When the DNA molecule or PS nanoparticles were added, the channel size effect caused different conductance. (3) by adding 位-DNA and carboxylation PS nanoparticles in different size channels, different bias voltage, buffer concentration, The current response of pH et al is studied. The mechanism of the influence of the above conditions on the current signal is analyzed by using the theories of surface charge, electroosmotic flow and double layer. It is found that the critical voltage decreases with the increase of the buffer pH, channel size. The effect of pH on SNR increases with the increase of buffer concentration: the greater the pH, the lower the SNR. (4) in the 100nm channel, the stable current I increases with the increase of pH. The critical voltage decreases with the increase of pH and decreases with the increase of buffer concentration. When the applied voltage is less than the critical voltage Uc, the absolute value of the stable current decreases with the increase of the voltage. By analyzing the current response signal and critical voltage, the motion characteristics of DNA,PS nanoparticles in the channel are discussed, which is helpful to the development of micro / nano-channel fluid sensors and biochips with special functions.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O441.1
本文编号：2426585
[Abstract]:In the practical application of micronano chip and biosensor, the control of single molecule can be realized accurately and flexibly by using the microfluid channel electric force driving operation and analyzing the characteristics of a single biological macromolecule. Based on the three-electrode system, the characteristic current signals of DNA and PS nanospheres traversing micro-nano channels (10 渭 m ~ 5 渭 m ~ (500 nm,200nm,100 nm) in diameter) driven by electric field force are studied systematically in this paper. It is found that the size of the microchannel, the solution pH and the buffer concentration all affect the current response signal of the micronano flow and the phenomenon of critical voltage appears. These are of great significance for the improvement of microfluidic technology and equipment and the improvement of signal-to-noise ratio (SNR). The main contents and conclusions of this paper include the following aspects: (1) the experimental results show that there are the same current phenomena in the channels of different sizes, that is, the initial current response has transient upward appreciation and transient decline. Then it changes over time and eventually stabilizes. Theoretical analysis shows that this is the result of electrode polarization and electroosmotic interaction under the influence of double layer. (2) the current signal of DNA molecule / PS nanoparticles solution in microchannel / nanowires is studied. When only pure TBE solution is added into the channel, the conductance does not decrease monotonously with the decrease of channel diameter, but increases with the decrease of channel diameter at sub-micron scale. The transient decrease of conductance of 200 nm channel was observed at applied voltage of 20 mV. When the DNA molecule or PS nanoparticles were added, the channel size effect caused different conductance. (3) by adding 位-DNA and carboxylation PS nanoparticles in different size channels, different bias voltage, buffer concentration, The current response of pH et al is studied. The mechanism of the influence of the above conditions on the current signal is analyzed by using the theories of surface charge, electroosmotic flow and double layer. It is found that the critical voltage decreases with the increase of the buffer pH, channel size. The effect of pH on SNR increases with the increase of buffer concentration: the greater the pH, the lower the SNR. (4) in the 100nm channel, the stable current I increases with the increase of pH. The critical voltage decreases with the increase of pH and decreases with the increase of buffer concentration. When the applied voltage is less than the critical voltage Uc, the absolute value of the stable current decreases with the increase of the voltage. By analyzing the current response signal and critical voltage, the motion characteristics of DNA,PS nanoparticles in the channel are discussed, which is helpful to the development of micro / nano-channel fluid sensors and biochips with special functions.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O441.1
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