Abstract-Determining terahertz resonant peaks of biomolecules in aqueous environment

Seo-Yeon Jeong, Hwayeong Cheon, Donggun Lee, and Joo-Hiuk Son

Sample holder for maintaining constant temperature of the sample. (a) Structure of sample holder. Inside the holder, a pair of thermoelectric cooling devices were in contact with the copper plate. The thermoelectric devices were cooled by the water cooler. The copper plate had a hole in the middle, and the quartz window was mounted inside the hole. (b) Process of filling liquid sample inside the container. The z-cut quartz window was fixed with a cylinder ring. The 300-µm copper spacer was placed on the z-quartz window. The liquid sample was dropped in the middle of spacer and covered with a Teflon window for 5 min. The Teflon window was removed after the sample was fully frozen, and the experiments were performed at an equilibrium temperature of 250 K.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-3-3854

The resonant peaks of biomolecules provide information on the molecules’ physical and chemical properties. Although many biomolecules have resonant peaks in the terahertz region, it is difficult to observe their specific signals in aqueous environments. Hence, this paper proposes a method for determining these peaks. We found the specific resonant peaks of a modified nucleoside, 5-methlycytidine and modified HEK293T DNA in an aqueous solution through baseline correction. We evaluated the consistency of various fitting functions used for determining the peaks with various parameters. We separated two resonance peaks of 5-methlycytidine at 1.59 and 1.97 THz and for artificially methylated HEK293T DNA at 1.64 and 2.0 THz.

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