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Edwards, G., Logan, R., Copeland, M., Reinisch, L., Davidson, J., Johnson, B., Maciunas, R., Mendenhall, M., Ossoff, R., Tribble, J., Werkhaven, J. and O’Day, D. (1994) Tissue Ablation by a Free-Electron Laser Tuned to the Amide II Band. Nature, 371, 416-419.

has been cited by the following article:

• TITLE: Synchrotron-Infrared Microscopy Analysis of Amyloid Fibrils Irradiated by Mid-Infrared Free-Electron Laser

  AUTHORS: Takayasu Kawasaki, Toyonari Yaji, Takayuki Imai, Toshiaki Ohta, Koichi Tsukiyama

  KEYWORDS: Amyloid Fibrils, Free-Electron Laser, Infrared Microscopy, Synchrotron Radiation

  JOURNAL NAME: American Journal of Analytical Chemistry, Vol.5 No.6, April 23, 2014

  ABSTRACT: Amyloid fibrils are widely recognized as a cause of serious amyloidosis such as Alzheimer’s disease. Although dissociation of amyloid fibril aggregates is expected to lead to a decrease in the toxicity of the fibrils in cells, the fibril structure is robust under physiological conditions. We have irradiated amyloid fibrils with a free-electron laser (FEL) tuned to mid-infrared frequencies to induce dissociation of the aggregates into monomer forms. We have previously succeeded in dissociating fibril structures of a short peptide of the thyroid hormone by tuning the oscillation frequency to the amide I band, but the detailed structural changes of the peptide have not yet been determined at a high spatial resolution. Synchrotron-radiation infrared microscopy (SR-IRM) is a powerful tool for in situ analysis of minute structural changes of various materials, and in this study, the feasibility of SR-IRM for analyzing the microscopic conformational changes of amyloid fibrils after FEL irradiation was investigated. Reflection spectra of the amyloid fibril surface showed that the amide I peaks shifted to higher wave numbers after the FEL irradiation, indicating that the initial β-sheet-rich structure transformed into a mixture of non-ordered and turn-like peptide conformations. This result demonstrates that conformational changes of the fibril structure after the FEL irradiation can be observed at a high spatial resolution using SR-IRM analysis and the FEL irradiation system can be useful for dissociation of amyloid aggregates.