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Track-etched Single Nanopores: Advanced Characterisation and New Applications

Final Report Summary - NANO-CHAPP (Track-etched single nanopores: Advanced characterisation and new applications)

This fellowship successfully developed the career of the researcher to the point where he is in a very strong position to lead an academic or industrial research group. The fellowship allowed him to complement his existing scientific knowledge with comprehensive expertise on nanopore fabrication, characterisation and applications. It also allowed him to gain training in complementary skills such as proposal writing, teaching and management. He built collaborations and made himself well-known throughout his research field through publications, collaboration and conference attendance. A second aim of the fellowship was to transfer back to the European Union the leading scientific expertise on characterisation, modelling and application of track-etched nanopores only available at the Siwy Research Group at the University of California Irvine, United States of America (USA) and to build long term collaborative links from this group and institution to the return host, the Photodetection and Imaging Research Group at University College Cork, Ireland. The scientific research and training objectives for this fellowship focused on single nanopores of diameters 2 to 50 nm, which are being explored for a wide range of applications, from single-molecule deoxyribonucleic acid (DNA) analysis, to biotoxin sensing, to creating ionic equivalents of electronic diodes and transistors.

During the course of the fellowship, the researcher received scientific training, training relevant to career development and carried out scientific research. Scientific training covered the operation of a range of electron and optical microscopes, fabrication and chemical modification of track-etched nanopores and cleanroom microfabrication techniques. The researcher developed skills important for career development by teaching, supervising undergraduate and postgraduate students, writing grant proposals and managing research projects. Scientific research was carried out in several directions. The first involved fabrication and characterisation of track-etched nanopores in silicon-nitride membranes and the researcher was part of the team to first achieve this. The noise characteristics of these nanopores were also studied. Two journal articles were published on this work (1, 2). The second direction focused on virus detection and analysis with nanopores, based on the resistive-pulse sensing method. This project has produced some very interesting data that reveals information about the nanopore substructure and details of the trajectories of particles passing through the pore. These results indicate that the nanopore substructure can be exploited to count particles significantly faster than can be achieved with the current technology. In addition, it suggests that particles of the same volume but different shapes can be distinguished, which has not been demonstrated to date with resistive-pulse sensing. Articles on this topic have also been published (3, 4). The third direction was nanopore-based DNA analysis. Here, the researcher was a central member of the team to first demonstrate DNA translocation through a graphene nanopore. The journal article describing this work has already been heavily cited (5). The researcher also worked on some other projects, including fabrication of metal nanotubes and the development and characterisation of hydrophobic nanopores. Articles have been published on both, which are cited as (6, 7) respectively.

The potential impact of this research includes improved healthcare, resulting from faster and lower cost DNA analysis tools, new methods for virus analysis, particle counting and new nanopore-based drug delivery methods. With respect to career development, the skills and training gained by the researcher put him in an excellent position to move on to the next stage of his career.

Articles cited:

1. I. Vlassiouk, P.Yu. Apel, S.N. Dmitriev, K. Healy, Z.S. Siwy, "Versatile Ultrathin Nanoporous Silicon Nitride Membranes", Proc. Natl. Acad. Sci. USA, 106, 21039-21044, 2009.
2. M.R. Powell, N. Sa, M. Davenport, K. Healy, I. Vlassiouk, S.E. Letant, L.A. Baker and Z. Siwy, "Noise properties of rectifying nanopores", J. Phys. Chem. C, 115, 8775-8783, 2011.
3. M. Pevarnik, K Healy, M.E. Toimil-Molares, A. Morrison, S.E. Létant, Z.S. Siwy, "Polystyrene Particles Reveal Pore Substructure as They Translocate", ACS Nano, 6, 7295-7302, 2012.
4. M. Davenport, K. Healy, M. Pevarnik, N. Teslich, S. Cabrini, A. Morrison, Z. Siwy, S. Letant, "The Role of Pore Geometry in Single Nanoparticle Detection", ACS Nano, 6, 8366-8380, 2012.
5. C.A. Merchant, K. Healy, M. Wanunu, V. Ray, N. Peterman, J. Bartel, M.D. Fischbein, K. Venta, Z. Luo, A. T. Johnson, M. Drndic, "DNA translocation through graphene nanopores", Nano Lett., 10, 2915-2921, 2010.
6. M. Davenport, K. Healy, Z. Siwy, "Ag nanotubes and Ag/AgCl electrodes in nanoporous membranes", Nanotechnology, 22, 155301, 2011.
7. M. Pevarnik, K. Healy, M. Davenport, J. Yen and Z. Siwy, "Hydrophobic interactions enhance ion current rectification in asymmetric nanopores", Analyst, 137, 2944-2950, (2012).