Abstract-Label-Free Measurements on the Solution of Monomeric and Dimeric Insulin Using a Periodical Terahertz Split Ring Resonator

Pengfei Wang, Liyuan Liu,  Xiangchao Wang, Jianbing Zhang, Wei Qi, Hongwei Zhao, Zhen Tian, Mingxia He



https://www.sciencedirect.com/science/article/abs/pii/S0301010419300035

A silicon-based sensor, consisting of periodical split ring resonators was demonstrated to monitor monomeric and dimeric insulin solutions in terahertz time-domain spectroscopy (THz-TDS). As concentration increases, the resonant frequencies of sensor show red shifts with a rapid trend in dilute solutions and a slow trend in concentrated solutions, consistent with CST simulations. For monomeric insulin, the turning concentration is 11.6mg/ml and the total frequency shift is larger than that of dimeric insulin which shows a turning concentration at 17.4mg/ml. The deviation in frequency shift and turning concentration can be attributed to the structural changes of insulin during dimerization process.

Abstract-Self-Assembled Chiral Nanoribbons Studied by Terahertz Time-Domain Spectroscopy and Other Biological Methods

Pengfei Wang, Yuefei Wang, Liyuan Liu, Jinwu Zhao, Zhen Tian, Wei Qi, Jianbing Zhang, Hongwei Zhao, Mingxia He



https://www.sciencedirect.com/science/article/abs/pii/S0009261419300363

We report the use of terahertz time-domain spectroscopy (THz-TDS) to probe chiral self-assembled twisted nanoribbons from a ferrocene-modified dipeptide consisting of two L-amino acids (Fc-FF). Supported by molecular dynamics simulation, the THz absorption peaks at 0.9 THz and 2.7 THz are attributed to distinct characteristic vibrational modes of Fc-FF single crystal. The relative absorption intensity is introduced to characterize the discrepancy in THz peak absorption which originates from symmetry breaking. Combined with the results of scanning electron microscopy, circular dichroism, Fourier transform infrared spectroscopy and X-ray diffraction, THz-TDS unravels great potentials to distinguish subtle structural changes within chiral self-assembled materials.