Lee, Dong-Kyu Yang, Heehong Hyun, Seok Song Park, Byeongho Hur, Eun-Mi Kim, Jae Hun Park, Tai Hyun Seo, Minah 2024-01-19T21:31:44Z 2024-01-19T21:31:44Z 2021-09-05 2018-11 0925-4005 https://pubs.kist.re.kr/handle/201004/120726 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. English Elsevier BV Ultrasensitive terahertz molecule sensor for observation of photoinduced conformational change in rhodopsin-nanovesicles Article 10.1016/j.snb.2018.07.052 1 Sensors and Actuators, B: Chemical, v.273, pp.1371 - 1375 Sensors and Actuators, B: Chemical 273 1371 1375 N scie scopus 000441519000166 2-s2.0-85049872214 Chemistry, Analytical Electrochemistry Instruments & Instrumentation Chemistry Electrochemistry Instruments & Instrumentation Article TIME-DOMAIN SPECTROSCOPY ALL-TRANS ISOMERIZATION SPECTRA VISION Terahertz spectroscopy Metamaterial Photoreceptor Conformational change