基于单分子成像技术研究λ-DNA分子穿越微米通道端口的电动力学特性  

Electrodynamic characteristics of λ-DNA molecule translocating through the microfluidic channel port studied with single molecular fluorescence imaging technology

作　　者：王琼[1,2] 王凯歌 孟康康[1] 孙聃 韩仝雨[1] 高爱华 Wang Qiong;Wang Kai-Ge;Meng Kang Kang;Sun Dan;Han Tong Yu;Gao Ai-Hua(National Center for International Research of Photoelectric Technology and Nano-Functional Materials and Application,State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials,Laboratory of Photoelectric Technology of Shaanxi Province,Institute of Photonics and Photon-Technology,Northwest University,Xi’an 710069,China;School of Physics,Northwestern University,Xi’an 710069,China)

机构地区：[1]西北大学光子学与光子技术研究所,国家级光电技术与纳米功能材料和应用国际研究中心,省部共建国家光电技术与功能材料重点实验室培育基地,陕西省光电子技术重点实验室,西安710069 [2]西北大学物理学院,西安710069

出　　处：《物理学报》2020年第16期285-295,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61378083,61405159);国家科学技术部中美合作基金项目(批准号:2011DFA12220);国家自然科学基金重大基础研究计划培育项目(批准号:91123030);陕西省自然科学研究基础研究计划-重大基础研究项目(批准号:2016ZDJC-15,S2018-ZC-TD-0061)资助的课题。

摘　　要：操控单个DNA分子,将其有效引入、导出微纳通道是实现DNA生物芯片功能的前提条件.本文利用单分子荧光显微成像技术系统地实时观察分析λ-DNA单分子在电场力驱动下进入/穿出50μm通道端口处的电动力学特性及规律.研究发现:λ-DNA分子能够顺利进入trans端口并穿出cis端口,外加电场强度存在最大(Emax)和最小(Emin)阈值,只有场强E满足:Emin≤E≤Emax时, λ-DNA分子才能进入trans端口并顺利穿出cis端口;当电场强度小于最小阈值场强时, DNA分子不能进入trans端口;当电场强度大于最大阈值场强时, λ-DNA分子虽可能从trans端口进入通道内部,但不容易从cis端口穿出,而是在迁移至通道内cis端口附近时,运动方向反转、往复、甚至旋转等新现象,并且易于粘附到管壁上;随着场强增大,反转位置距cis端口越大.基于微流体电动力学理论,对λ-DNA分子在微通道端口的不同运动状态的物理机制进行了初步分析.本研究结果对研制基于微纳通道系统的基因芯片实验室及DNA分子传感器具有一定的实际指导意义.Manipulating a single DNA molecule and effectively introducing it into and exporting micro-nano-fluidic channels are prerequisites for the functional DNA biochips. And it is the key to the precise separation and screening of different DNA molecules by the micro-/nanochannel system that accurately understanding the movement characteristics and dynamic mechanism of DNA molecules moving near the channel port. In this paper, the electrodynamic characteristics of λ-DNA molecule entering into/leaving off a 50 μm channel port driven by the electric field force are systematically investigated and analyzed by the single molecule fluorescence microscopy. The experimental results indicated that there were the maximum(Emax) and minimum(Emin)thresholds of the applied electric field intensity, and only when the field intensity E meets Emin ≤ E ≤ Emax,the single λ-DNA molecule could successfully enter into the trans port and exit out of the cis port;when the electric field intensity was less than the minimum threshold, E ≤ Emin, λ-DNA molecules could not enter the trans port;when the electric field intensity was greater than the maximum threshold, Emax ≤ E, λ-DNA molecules could move into the microchannel through the trans port, but not exit out of the cis port. When lDNA molecule migrated toward the cis port along the channel, the movement state was changed, some new phenomena were observed, e.g. the translocation direction was reversed, reciprocated, or even rotated;moreover, the DNA molecules were easy to adhere to the channel wall. In addition, when the electric field intensity enhanced, the distance between the position where DNA molecular direction reversing and the cis port was increased. Based on the microfluidic electrodynamics, the physical mechanism of the velocities and translocation states of single λ-DNA molecule passing microchannel port was preliminarily analyzed. The results of this study have certain practical guiding significance for the development of gene chip laboratory and DNA molecular sens

关 键 词：DNA 分子 单分子荧光成像技术 微流通道 反转运动 

分 类 号：TN492[电子电信—微电子学与固体电子学] O657.3[理学—分析化学]