Development of Ultrasensitive Terahertz ESR Spectroscopy for Metalloprotein Using a Microcantilever

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 37; no. 12; pp. 1173 - 1184
• Main Authors: Okamoto, Tsubasa, Takahashi, Hideyuki, Ohmichi, Eiji, Ohta, Hitoshi
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2016; Springer Nature B.V
• Subjects: Classical Electrodynamics; Displacement; Electrical Engineering; Electron paramagnetic resonance; Electron spin; Electron spin resonance; Electronics and Microelectronics; Engineering; Feasibility analysis; Feasibility studies; Fiber optics; Infrared; Instrumentation; Optical fibers; Porphyrins; Sensitivity analysis; Spin resonance; Terahertz (THz); Electron spin resonance; Metalloprotein; Microcantilever
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-016-0305-6

In this article, we report a novel method for ultrasensitive high-frequency electron spin resonance (HFESR) using a microcantilever. With this method, a field-gradient force exerting on a sample-holding cantilever is detected as cantilever displacement. A unique feature of this method is that a very tiny sample (~1 µg) is sufficient for HFESR measurement in the terahertz region. Thus, the application of this method to metalloprotein is expected to be of particular interest in the future. In this study, we developed two types of HFESR techniques: one for fiber-optic detection and the other for piezoresistive detection. We applied these techniques to multi-frequency HFESR measurements of metal-containing porphyrin compounds as a model metalloprotein substance and evaluated the sensitivity and feasibility of each technique.