Direct observation of λ-DNA molecule reversal movement within microfluidic channels under electric field with single molecule imaging technique  

作　　者：杨凤云 王凯歌 孙聃 赵伟 王海青 何鑫 王归仁 白晋涛 

机构地区：[1]Institute of Photonics & Photo-Technology, National Center for International Research of Photoelectric Technology & Nano-functional Materials,State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials,Key Laboratory of Optoelectronic Technology of Shaanxi Province, Northwest University [2]Mechanical Engineering Department & Biomedical Engineering Program, University of South Carolina

出　　处：《Chinese Physics B》2016年第7期525-533,共9页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.61378083);the International Cooperation Foundation of the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2011DFA12220);the Major Research Plan of National Natural Science Foundation of China(Grant No.91123030);the Natural Science Foundation of Shaanxi Province of China(Grant Nos.2010JS110 and2013SZS03-Z01)

摘　　要：The electrodynamic characteristics of single DNA molecules moving within micro-/nano-fluidic channels are important in the design of biomedical chips and bimolecular sensors. In this study, the dynamic properties of λ-DNA molecules transferring along the microchannels driven by the external electrickinetic force were systemically investigated with the single molecule fluorescence imaging technique. The experimental results indicated that the velocity of DNA molecules was strictly dependent on the value of the applied electric field and the diameter of the channel. The larger the external electric field, the larger the velocity, and the more significant deformation of DNA molecules. More meaningfully, it was found that the moving directions of DNA molecules had two completely different directions：（i） along the direction of the external electric field, when the electric field intensity was smaller than a certain threshold value;（ii） opposite to the direction of the external electric field, when the electric field intensity was greater than the threshold electric field intensity.The reversal movement of DNA molecules was mainly determined by the competition between the electrophoresis force and the influence of electro-osmosis flow. These new findings will theoretically guide the practical application of fluidic channel sensors and lab-on-chips for precisely manipulating single DNA molecules.The electrodynamic characteristics of single DNA molecules moving within micro-/nano-fluidic channels are important in the design of biomedical chips and bimolecular sensors. In this study, the dynamic properties of λ-DNA molecules transferring along the microchannels driven by the external electrickinetic force were systemically investigated with the single molecule fluorescence imaging technique. The experimental results indicated that the velocity of DNA molecules was strictly dependent on the value of the applied electric field and the diameter of the channel. The larger the external electric field, the larger the velocity, and the more significant deformation of DNA molecules. More meaningfully, it was found that the moving directions of DNA molecules had two completely different directions：（i） along the direction of the external electric field, when the electric field intensity was smaller than a certain threshold value;（ii） opposite to the direction of the external electric field, when the electric field intensity was greater than the threshold electric field intensity.The reversal movement of DNA molecules was mainly determined by the competition between the electrophoresis force and the influence of electro-osmosis flow. These new findings will theoretically guide the practical application of fluidic channel sensors and lab-on-chips for precisely manipulating single DNA molecules.

关 键 词：reversal movement electrophoresis electroosmosis electric field threshold value 

分 类 号：Q503[生物学—生物化学]