2017 Fiscal Year Research-status Report
Isothermal DNA Sequencing by Diffusion Current in a MoS2 Nanopore
| Project/Area Number |
17K17682
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| Research Institution | The University of Tokyo |
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Principal Investigator |
徐 偉倫 東京大学, 大学院工学系研究科(工学部), 助教 (50771549)
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Keywords | Nanopore / DNA sequencing / 2D material / Ion transport / Electrokinetics / Precision medicine / Drug delivery / Diffusiophoresis |
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| Outline of Annual Research Achievements |
We have achieved tremendous progress in both theoretical and experimental parts. On the theoretical side, we have investigated electrokinetic phenomena inside a nanopore for the targeting system. Joule heating effects, viscoelectric effects and current variation in a salt concentration biased two-dimensional nanopore during the translocation event of a DNA molecule have been studied. It is found that the proposed sensing method using diffusion current can effectively reduce Joule heat inside a nanopore to prevent denature of DNA molecules for more accurate sensing measurements. We also have identified nonlinear electroosmotic behavior due to the presence of viscoelectric effects arising from the orientation of water molecules in the vicinity of a charged nanopore surface, which is important to DNA translocation behavior. Part of our theoretical results has been published in a prestigious international journal, The Journal of Physical Chemistry C, under American Chemical Society.
For experiments, we have prepared a nanopore supporter using focused ion beam for the transfer of a molybdenum disulfide nanopore. An opening was made on top of a silicon chip covered by a silicon nitride thin layer. The molybdenum disulfide ultra-thin layer has been successfully put onto this opening. In the meanwhile, an ultra-low noise current measurements system has been developed for highly sensitive DNA sequencing. Based on our tests that the current measurements system demonstrates outstanding noise reduction performance enabling to suppress the noise down to sub-5 picoamperes.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Through attending top-tier international conferences, I have successfully made connection and collaboration to influential scientists who are leading in the field making our project progress much more smoothly than initially planned.
We work with one of the pioneering scientists, Professor Yoshihiro Iwasa, of two-dimensional materials at the Department of Applied Physics, The University of Tokyo for the fabrication of a molybdenum disulfide nanopore. In the meanwhile, we have received enormous help on noise reduction for current measurements from our international collaborators, Professor Yi-Tao Long and Professor Yi-Lun Yin, at Key Laboratory for Advanced Materials & School of Chemical and Molecular Engineering, East China University of Science and Technology. Professor Yi-Tao Long is an Associate Editor of a high impact journal in sensing area, ACS Sensors, under American Chemical Society who has extensive experience in development of cutting-edge sensing devices. For temperature measurements inside a nanopore, we collaborate with Professor Jean-Jacques Delaunay at the Department of Mechanical Engineering, The University of Tokyo, who is a world-recognized expert in optical physics. We will use dark-field microscopy to trace temperature variation by measuring the fluorescence response of a fluorescein electrolyte solution. For modeling, we work with a computational simulation team organized by Professor Dalton Harvie, Professor Dave Dunstan and Professor Malcolm Davidson. Using an implicit finite volume method, we have successfully simulated our nanopore system.
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| Strategy for Future Research Activity |
In the second year, we will finalize both our experimental and theoretical work in this project. Due to the foreseeable success and huge significance of our work, we will submit our results to high ranking international journals to impact on scientists in the research field of nanopore sensing and medical diagnostics.
Also, we will submit a patent of our novel DNA sequencing method. We have contacted a patent agency at the University of Tokyo, TODAI TLO, Ltd., as long as our experiments show successful results we can prepare and issue the patent very shortly. This patent will help us launch a start-up company through a venture capital platform, The University of Tokyo Edge-Capital (UTEC), to directly impact the society. To borrow valuable experience, I have visited a team at Osaka University led by Professor Masateru Taniguchi whose team Quantum Biosystems Inc. raised Series B funding of 2.4 billion yen in 2015 through the UTEC. We will follow a similar model to manage our company.
Meanwhile, we will also apply the established methods to detect various biomolecules for precision medicine applications. Furthermore, the developed two-dimensional nanopore system will be harnessed to resolve not only medical and sensing issues but also energy related and environmental problems, such as batteries, water purification and energy harvesting. For these applications, we will need an array of two-dimensional material nanopores. We plan to achieve these by using e-beam patterning and reactive ion etching at a super clean room, TakedaCR, The University of Tokyo.
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Research Products
(6 results)
