SEMINAR

Ultrafast propagation of A(beta) fibrils in oligomeric cloud studied by TIRFM-QCM

Abstract
We monitored the deposition reaction of A(beta)1–40 peptides on immobilized seeds grown from A(beta)1–42, which caused formation of oligomers in the early stage [1]. The deposition reaction and fibrillation procedure were monitored throughout by novel total-internal-reflection-fluorescence microscopy with a quartz-crystal microbalance (TIRFM-QCM) system [2]. This system allows simultaneous evaluation of the amount of deposited peptides on the surface seeds by QCM and fibril nucleation and elongation by TIRFM. Most fibrils reached other nuclei, forming the fibril network across the nucleus hubs in a short time. We found a fibril-elongation rate two-orders-of-magnitude higher in an oligomeric cloud than reported values, indicating ultrafast transition of oligomers into fibrils.

References
[1] Ogi, H. et al. (2011) Seed-dependent deposition behavior of Ab peptides studied with wireless quartz-crystal-microbalance biosensor. Anal. Chem. 83, 4982-4988.

[2] Ogi, H. et al. (2014) Ultrafast propagation of b-amyloid fibrils in oligomeric cloud. Sci. Rep. 4, 6960.

BIOGRAPHY

2000-present: Associate Professor, Graduate School of Engineering Science, Osaka University
2012: JSPS Prize
1998-1999: Guest Researcher, National Institute of Standards and Technology in USA
1997: PhD, Graduate School of Engineering Science, Osaka University
1993-1998: Research Associate, Graduate School of Engineering Science, Osaka University

Research Fields and Interests:
Materials science and bioscience with originally developed acoustic methods, including picosecond ultrasonic spectroscopy, wireless-electrodeless ultra-sensitive quartz-crystal-microbalance biosensors, and electromagnetic acoustic resonance.

Selected Publications:
Ogi, H, Fukukshima, M., Hamada, H., Noi, K., Hirao, M., Yagi, H., and Goto, Y. (2014) Ultrafast propagation of β-amyloid fibrils in oligomeric cloud. Sci. Rep. 4, 6960.

Tanigaki, K., Ogi, H., Sumiya, H., Kusakabe, K., Nakamura, N., Hirao, M., and Ledbetter, H. (2013) Observation of higher stiffness in nanopolycrystal diamond than monocrystal diamond. Nat. Commun. 4, 2343.

Ogi, H. (2013) Wireless-electrodeless quartz-crystal-microbalance biosensors for studying interactions among biomolecules: A review. Proc. Jpn. Acad. Ser. B 89, 401-417..

Ogi, H., Nagai, H., Fukunishi, Y., Hirao, M., and Nishiyama, M. (2009) 170-MHz electrodeless quartz crystal microbalance biosensor: Capability and limitation of higher frequency measurement. Anal. Chem. 81, 8068-8073.

Ogi, H., Fujii, M., Nakamura, N., Yasui, T., and Hirao, M. (2007) Stiffened ultrathin Pt films confirmed by acoustic-phonon resonances. Phys. Rev. Lett. 98, 195503.