Abstract-Terahertz Spectroscopic Signatures of Microcystin Aptamer Solution Probed with a Microfluidic Chip

Mingkun Zhang, Zhongbo Yang, Mingjie Tang , Deqiang Wang , Huabin Wang, Shihan Yan , Dongshan Wei,  Hong-Liang Cui

https://www.mdpi.com/1424-8220/19/3/534

Terahertz signature detection of biological samples in aqueous solution remains a great challenge due to the strong terahertz absorption of water. Here we propose a new preparation process for fabricating a microfluidic chip and use it as an effective sensor to probe the terahertz absorption signatures of microcystin aptamer (a linear single-stranded DNA with 60 nucleotides) dissolved in TE buffer with different concentrations. The microfluidic chip made of silicon includes thousands of 2.4 μm × 2.4 μm square-cross-section channels. One repeatable terahertz absorption signature is detected and recognized around 830 GHz, fitted to a Lorentz oscillator. This signature is theorized to originate from the bending of hydrogen bonds formed between adjacent hydrated DNA bases surrounded by water molecules. Furthermore, the low-lying vibrational modes are also investigated by molecular dynamics simulations which suggest that strong resonant oscillations are highly probable in the 815–830 GHz frequency band

Abstract-Reflection type scanning laser terahertz near-field spectroscopy and imaging system for bio-applications

Kosuke Okada, Kazunori Serita, Iwao Kawayama, Hironaru Murakami, and Masayoshi Tonouchi

https://www.osapublishing.org/abstract.cfm?URI=cleo_si-2018-SW3D.4

We developed a reflection type scanning laser THz near-field spectroscopy and imaging system and evaluated its basic performance. We found that this system has huge potential for high-resolution, high-sensitive and high-speed biological measurements.

© 2018 The Author(s)

Abstract-Sensing viruses using terahertz nano-gap metamaterials

S. J. Park, S. H. Cha, G. A. Shin, and Y. H. Ahn

https://www.osapublishing.org/boe/abstract.cfm?uri=boe-8-8-3551

We demonstrate highly sensitive detection of viruses using terahertz split-ring resonators with various capacitive gap widths. Two types of viruses, with sizes ranging from 60 nm (PRD1) to 30 nm (MS2), were detected at low densities on the metamaterial surface. The dielectric constants of the virus layers in the THz frequency range were first measured using thick films, and the large values found identified them as efficient target substances for dielectric sensing. We observed the resonance-frequency shift of the THz metamaterial following deposition of the viruses on the surface at low-density. The resonance shift was higher for the MS2 virus, which has a relatively large dielectric constant. The frequency shift increases with surface density until saturation and the sensitivity is then obtained from the initial slope. Significantly, the sensitivity increases by about 13 times as the gap width in the metamaterials is decreased from 3 µm to 200 nm. This results from a combination of size-related factors, leading to field enhancement accompanying strong field localization.

© 2017 Optical Society of America

Abstract-Fast design of broadband terahertz diffusion metasurfaces

Jie Zhao, Qiang Cheng, Tian Qi Wang, Wei Yuan, and Tie Jun Cui

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-2-1050

A method for fast design of broadband terahertz diffusion metasurface is presented. The proposed metasurface is composed by three kinds of simply patterned elements with different resonant properties. To obtain the best broadband performance with the lowest backward reflections, a genetic algorithm is developed to manipulate the resonances for the fast determination of element geometries. An inverse discrete Fourier transform method is used to predict the scattering pattern of the metasurface with high accuracy and low time consumption, significantly enhancing the efficiency of the array-pattern design. The proposed fast design flow will benefit a broad range of terahertz applications, such as biological detection and imaging.

© 2017 Optical Society of America

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