Terahertz time-domain spectroscopy and imaging of artificial RNA

Abstract

Abstract:We use terahertz time-domain spectroscopy (THz-TDS) to measure the far-infrared dielectric function of two artificial RNA single strands, composed of polyadenylic acid (poly-A) and polycytidylic acid (poly-C). We find a significant difference in the absorption between the two types of RNA strands, and we show that we can use this difference to record images of spot arrays of the RNA strands. Under controlled conditions it is possible to use the THz image to distinguish between the two RNA strands. We discuss the requirements to sample preparation imposed by the lack of sharp spectral features in the absorption spectra.

A Novel Terahertz Sensing Device Comprising of a Parabolic Reflective Surface and a Bi-Conical Structure

“…is the E-field of the near field without the presence of sample material, E (1) sample (t) is the E-field generated by the interaction between the incident THz wave and the sample material, and n (1) (t) is the noise from the system and environment.…”

“…Terahertz (THz) sensing technology has received considerable attention in recent years for its potential applications in the detection of biological materials, skin cancer and spectral signature for molecular vibrations in RNA, DNA strands or proteins [1][2][3][4][5][6][7].…”

“…Typically, the sample material is located in the path way between a THz source and a detector. In this case, the sample material interacts with a THz wave from the source and the forward scattered wave is received by a THz detector [1,4,5]. Attenuated total reflection (ATR) is also introduced for THz sensing while the THz beam is redirected by a prism toward the sample material [3].…”

“…The noise figure of THz detector by photoconductive antenna is high, so that a high signal to noise ratio (SNR) is required to extract the THz signal from the signal received. Parabolic mirrors have been widely used in THz systems to focus the weak THz power to the sample to increase the SNR [1][2][3][4][5][6]. On the other hand, a bi-conical structure has been widely used as a broadband radiation device with very high field concentration at gaps between the conical structure [12,13].…”

Support Vector Machine Applications in Terahertz Pulsed Signals Feature Sets

“…The classification of two different types of ribonucleic acid (RNA) samples is of importance because it is a potential precursor for deoxyribonucleic acid (DNA) sample classification in an in vivo environment [10]. We also classify six different types of powder materials, to illustrate the validity of our approach to other applications, such as security.…”