Ultrasensitive terahertz molecule sensor for observation of photoinduced conformational change in rhodopsin-nanovesicles

Title
Ultrasensitive terahertz molecule sensor for observation of photoinduced conformational change in rhodopsin-nanovesicles
Authors
김재헌서민아이동규박병호양희홍송현석허은미박태현
Keywords
terahertz; photoreceptor; metamaterials
Issue Date
2018-11
Publisher
Sensors and actuators. B, Chemical
Citation
VOL 273-1375
Abstract
Elucidating molecular mechanisms of rhodopsin signal transduction is crucial for understanding photo-reaction process and vision. In particular, a conformational change of retinal from 11-cis to all-trans configuration initiates a chain reaction. Earlier studies on photoinduced isomerization provided that chromophore retinal has torsional vibration modes related to the photoisomerization dynamics at very low frequency regime, including terahertz (THz) frequency. However, limited success has been made in detecting such change using low frequency electromagnetic wave, due to its extremely small absorption cross section within allowed signal-to-noise level. Here, we developed an ultrasensitive terahertz molecule sensor that allows us to detect the conformational change from 11-cis to all-trans state of retinal embedded in photoreceptor-nanovesicles. Nano-slot antenna array fabricated onto SiO2/Si substrate was used as a sensing chip for enhancing THz reflection signal change under photo excitation. In particular, THz top-down reflection system in normal geometry enabled us to measure extremely small changes in signal by dramatically reducing undesired light paths through several substrates, cover glass, and the absorptive sample itself, all of which comprise unavoidable parts in typical transmission measurement cases. Moreover, a direct monitoring of a photo-induced conformational change in photoreceptors could be performed at room temperature and in a label-free and a non-contact manner.
URI
http://pubs.kist.re.kr/handle/201004/67839
ISSN
0925-4005
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KIST Publication > Article
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