Abstract-Terahertz absorption characteristics of guar gum determined via microfluidic technology

 

Feng-Xuan Zhang, Guo-Yang Wang, Hai-Yun Huang, Meng-Han Chen, Si-Jia Zhang, Bo Su,  Cun-Lin Zhang 

https://jeos.springeropen.com/articles/10.1186/s41476-021-00162-x

The vibrational energy levels of many biomolecules correspond to the terahertz band; thus, terahertz technology can be used to identify these substances. Moreover, as the biological activity of most biomolecules can be observed only in aqueous solution, the characteristics of such biomolecules must be studied in aqueous solution. In this study, a simple microfluidic chip, a temperature control device and a strong electric field device were designed to study the terahertz absorption characteristics of guar gum for different temperatures, concentrations and electric field exposure durations, thus enabling the use of terahertz technology to analyse the characteristics of guar gum.

Abstract-Terahertz Absorption Properties of Two Solid Amino Acids and Their Aqueous Solutions

 

Ping Ye,  Guoyang Wang,  Yizhou Yang, Qinghao Meng, Jiahui Wang, Bo Su, Cunlin Zhang

https://www.hindawi.com/journals/ijo/2021/9203999/

A new type of embedded cyclic olefin copolymer microfluidic chip was designed and combined with terahertz (THz) technology to study the effects of glycine and arginine on the THz wave absorption characteristics. This study aims to understand the interactions between solid amino acid molecules and between amino acid and water molecules and to determine the changes in their microstructure. By observing the intensity of the time domain spectra in the range of 0.2–2.6 THz, we found that, as the concentration of glycine and arginine increased, the THz transmission gradually decreased. It can be inferred that the molecular structure and quantity of different amino acids have different influence on the hydrogen bond, which affects the absorption coefficient in solution. It was also found that the terahertz technique is able to identify the solid amino acid species better, and it can also perform some species identification for liquid amino acids. These results provide a reference for future studies on the terahertz absorption properties of amino acid samples. Moreover, Gaussian16 software was used to calculate the terahertz spectra using the density functional theory, B3LYP functional, and 6-31G basis set. Additionally, Gaussian View6 video software provided the frequency values, molecular vibration modes of the theoretical absorption peaks of glycine, arginine, and its aqueous solutions in the frequency range of 0.2–2.6 THz, which offers theoretical support for future studies.

Abstract-Terahertz spectral analysis of different electrolytes

Yi-Wei Wen, Bo Su, Jia-Hui Wang, Guo-Yang Wang, Ya-Xiong Wu, Jing-Suo He, Cun-Lin Zhang,

 https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-59/issue-5/055107/Terahertz-spectral-analysis-of-different-electrolytes/10.1117/1.OE.59.5.055107.short

Terahertz (THz) technology has become popular worldwide as a new approach to detecting biomolecules because the vibrational and rotational energy levels of many biomolecules fall in the THz band and because the THz wave has the characteristics of low electronic energy, which will not damage the samples to be measured. Many biomolecules need to maintain their biological activity in liquid environment. However, as a polar molecule, water has a strong absorption of THz wave, which is mainly because the vibration frequency of hydrogen bond in aqueous solution is within the THz frequency range. Therefore, the best solution is to reduce the action distance between the aqueous solution and THz wave and control it within 100  μm. Microfluidic chips can meet such requirements. Therefore, the combination of THz technology and microfluidic technology can study the dynamic characteristics of biomolecules in an aqueous solution. The microfluidic chip was fabricated using ZEONOR 1420Rs. The THz transmittance of the material can exceed 95%. The depth of the microchannel in the microfluidic chip is 50  μm. In addition, the chip has the characteristics of good airtightness, portability, convenient disassembling, and reusability. Seventeen kinds of electrolytes were tested with the chip. The results show that the THz spectral intensity of electrolyte composed of different anions and cations, so the spectral characteristics of other electrolyte solutions can be obtained according to the spectral information of these detected ions.

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