Abstract-Quantitative characterization of bovine serum albumin thin-films using terahertz spectroscopy and machine learning methods

Yiwen Sun, Pengju Du, Xingxing Lu, Pengfei Xie, Zhengfang Qian, Shuting Fan, and Zexuan Zhu

https://www.osapublishing.org/boe/abstract.cfm?uri=boe-9-7-2917

The development of new spectral analysis methods in bio thin-film detection has generated intense interest in terahertz (THz) spectroscopy and its application in a wide range of fields. In this paper, it is the first time that machine learning methods are applied to the quantitative characterization of bovine serum albumin (BSA) deposited thin-films detected by terahertz time-domain spectroscopy. The spectra data of BSA thin-films prepared by solutions with concentrations ranging from 0.5 to 35 mg/ml are analyzed using the support vector regression method to learn the underlying model of the frequency against the target concentration. The learned mode successfully predicts the concentrations of the unknown test samples with a coefficient of determination R2 = 0.97932. Furthermore, aiming to identify the relevance of each frequency to the concentration, the maximal information coefficient statistical analysis is used and the three most discriminating frequencies in THz frequency are identified at 1.2, 1.1 and 0.5 THz respectively, which means a good prediction for BSA concentration can be achieved by using the top three relevant frequencies. Moreover, the top discriminating frequencies are in good agreement with the frequencies predicted by a long-wavelength elastic vibration model for BSA protein.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Investigate the effects of EG doping PEDOT/PSS on transmission and anti-reflection properties using terahertz pulsed spectroscopy

Yiwen Sun, Shengxin Yang, Pengju Du, Fei Yan, Junle Qu, Zexuan Zhu, Jian Zuo, and Cunlin Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-3-1723&origin=search

The conductivity of poly(3,4-ethylene dioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) is significantly enhanced on adding some organic solvent such as ethylene glycol (EG). In this paper, the optoelectronic properties of EG doped PEDOT/PSS on transmission and anti-reflection effects are investigated in detail by terahertz time domain spectroscopy (THz-TDS). The transmission line circuit theory gives us an insight into the THz transmission mechanisms of the main and second pulses. In particular, we show that the conductivities of 10% EG doped PEDOT/PSS are nearly frequency independent from 0.3 to 1.5 THz. To demonstrate applications of this property, we design and fabricate broadband terahertz neutral density filters and anti-reflection coatings based on 10% EG doped PEDOT/PSS thin films with varying thickness. Our measurements highlight the capability of THz-TDS to characterize the conductivity of EG doped PEDOT/PSS, which is essential for broadband optoelectronic devices in THz region.

© 2017 Optical Society of America