Electrochemical Properties Of DNA Molecules In Micro - Nano - Channels

Micro-/nanofludics chip because of characteristics such as carrying a variety of unit technology, flexible combination and scale integration so on, is used to study the properties of biomolecules nowdays. At present, the research on micro-/nanofludics chip or biosensor about biological analysis has caused attention widely. Studying clearly DNA molecular dynamics behaviors in micro-/nanofludics chip and exploring its dynamic characteristics under the action of electric field, which is an important theoretical guidance and practical value for the design of micro-/nanofludics equipment as well as the biological sensors. Firstly, in this article, by modifying the surface of silica micro-/nanochannel, we successfully introduce the DNA molecules into the micro-/nanochannel. Secondly, under the effect of electric field, the electrodynamics behavior of DNA molecules in microchannel were studied in detail.The whole work can be described by following three aspects:(1) Analyzing and summarizing the affecting factors about introducing the DNA molecules into the micro-/nanochannel. Therefore, we proposes a polymer coating modified method on the surface of the channel. Three different kinds of dynamic mechanism to implement the DNA molecule smoothly into and through the micro-/nanochannel, which is capillary force driven, electric field driven and diffusion, respectively. These experimental results provides a possibility for our next research about electrodynamics characteristics of DNA molecules in the micro-/nanochannel.(2)The influence factors of stretching states of DNA molecules in the micro-/nanochannel was studied. We recorded the DNA molecules’stretch state from 300 μm to 500 nm. The results shows that two major factors caused the deformation of DNA molecules which is the wall confined effect and flow velocity.(3) The electrodynamic properties of γ-DNA molecules moving within microfluidic channel are systemically studied. It is found that there exists a threshold voltage Eo, and only when the applied voltage is greater than the Eo, DNA molecules can successfully translocate through the channels. The E0 value is decided by the electrophoretic force on DNA molecule which is a minimum driving force that can introduce DNA into channels. In addition, the direction of DNA molecules moving within the microfluidic channels is decided by the competition between EP and EOF. The DNA molecule migration velocity is proportional to the strength of the applied electric field, under the same strength of the electric field, the velocity is approximately constant. These new findings have theoretical guidance for practical application of micro-/nano-channel sensors and Lab-chips based on the electrohydrodynamics and optofluidics.