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IBEC Seminar: Chia-Fu Chou
Friday, November 27, 2015 @ 12:00 pm–1:00 pm
Low-copy number biomolecular analysis with dielectrophoretic enrichment /trapping via molecular dam and plasmonic electrode nanogaps
Chia-Fu Chou, Senior Research Fellow/Professor, Institute of Physics, Academia Sinica, TaiwanNanoscale structures, such as electrode nanogap and nanofluidic confinement, given its simplicity in geometry, nevertheless offer unique platforms for the study of molecular and cellular biophysics, with the potential for bioanalytical applications [1-5]. For low-copy number molecule detection, we developed two versatile analysis platforms for the manipulation and sensing of biomolecules. In the first scenario, sub-30 nm insulating nanoconstriction operating under the balance of negative dielectrophoresis (DEP), electrophoresis, and electroosmosis, serves as molecular dam, enables protein enrichment of 105-fold in 20 seconds [6], which can then be coupled with graphene-modified electrode for sensitive electrochemical detection of proteins and peptides [7, 8]. In the second scenario, an array of Ti/Au electrode nanogaps with sub-10 nm gap size function as templates for AC DEP-based molecular trapping, plasmonic hot spots for surface-enhanced Raman spectroscopy as well as electronic measurements, and fluorescence imaging. During molecular trapping, recorded Raman spectra, conductance measurements across the nanogaps and fluorescence imaging show unambiguously the presence and characteristics of the trapped molecules, demonstrated with R-phycoerythrin [9] and Alzheimer’s disease associated biomarkers A-beta 40 and 42 peptides. Our platforms open up simple ways for multifunctional low-concentration heterogeneous sample analysis.
[1] L.J. Guo, X. Cheng, C.F. Chou, Nano Lett. 4, 69 (2004).
[2] J. Gu, R. Gupta, C.F. Chou, Q. Wei, F. Zenhausern, Lab Chip 7, 1198 (2007).
[3] J.W. Yeh, A. Taloni, Y.L. Chen, C.F. Chou, Nano Lett. 12, 1597 (2012). [Research Highlights, Nature 482, 442 (2012)].
[4] J.P. Shen and C.F. Chou, Biomicrofluidics 8, 041103 (2014).
[5] K.K. Sriram, J.W. Yeh, Y.L. Lin, Y.R. Chang, C.F. Chou, Nucleic Acids Res. 42, e85 (2014).
[6] K.T. Liao, C.F. Chou, J. Am. Chem. Soc. 134, 8742 (2012). [JACS Spotlights: JACS 134, 10307 (2012)]
[7] B. Sanghavi, W. Varhue, J. Chávez, C.F. Chou, N. S. Swami, Anal. Chem. 86, 4120 (2014,).
[8] B.J. Sanghavi, W. Varhue, A. Rohani, K.T. Liao, L. Bazydlo, C.F. Chou, N. S. Swami, Lab Chip 2015, DOI: 10.1039/c5lc00840a.
[9] L. Lesser-Rojas, P. Ebbinghaus, G. Vasan, M.L. Chu, A. Erbe, C.F. Chou, Nano Lett. 14, 2242 (2014).
