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Micro-/nanofluidics and single DNA dynamics in non-uniform electrokinetic flows

Wang, Shengnian

Abstract Details

2006, Doctor of Philosophy, Ohio State University, Chemical Engineering.
The purpose of this study is to fabricate polymer nanodevices and investigate micro-/nanofluidic and DNA dynamics in non-uniform electrokinetic flows. Single DNA dynamic deformation was firstly studied in cross-slot microfluidic platforms. Three basic flow patterns (i.e., extensional, shear and rotational flows) were generated and polystyrene nanospheres were used to identify the flow characteristics. The conformational evolution of lambda-DNA molecules was also investigated and it indicated that the initial conformation of molecules and their residence time in the flow play important roles in the dynamic of DNA stretching. A new nanonozzle array was developed by Sacrificial Template Imprinting (STI), which can provide more uniform and controllable DNA stretching compared to the cross-slot design. A polymer sacrificial template was used to avoid structure damage or defects during the de-molding process. It was produced by a two-step replication, starting with a conically shaped nanotip array. Each nanonozzle is 3 micrometer high with the size at the small end down to 80 nm. In conjuction with surface modification and silica synthesis on the surface, the channel size was further reduced and the polymer structure was reinforced. Further 2D dynamic complexation exhibited a two-stage complexation, extending gradually from the small end towards the large end. Nanonozzle can provide two important flow patterns: the converging flow and the diverging flow. 2D converging microchannels were used to investigate the migration behavior of rigid nanospheres and flexible DNA molecules. Vortices were observed both inside and at the small end of the converging channel. When nanoparticles have much smaller size than the channels (i.e., the hindered factor is small), for example, in dynamic assembly, non-uniform surface charge led to the formation of new vortex pair. The stagnation region between the double vortex pairs is believed to have the primary complexation. When hindered factor is large, hindered migration was shown in the diverging direction, while nanonozzles were easily clogged in the converging direction for rigid colloid nanospheres. But for flexible lambda-DNA molecules, their molecular chain can be stretched to achieve easy pass in the converging direction even though their equilibrium size are much larger than the channel size.
Ly Lee (Advisor)
274 p.

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Citations

  • Wang, S. (2006). Micro-/nanofluidics and single DNA dynamics in non-uniform electrokinetic flows [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002340

    APA Style (7th edition)

  • Wang, Shengnian. Micro-/nanofluidics and single DNA dynamics in non-uniform electrokinetic flows. 2006. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002340.

    MLA Style (8th edition)

  • Wang, Shengnian. "Micro-/nanofluidics and single DNA dynamics in non-uniform electrokinetic flows." Doctoral dissertation, Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002340

    Chicago Manual of Style (17th edition)