夹心式太赫兹微流控芯片

许多生物大分子的振动和转动能级都落在THz波段范围内，因此可以采用THz光谱技术定性地鉴别生物样品。但是大部分生物分子的活性需在液体环境中才能表现出来，而水作为极性物质对THz波具有较强的吸收特性。因此，在THz光谱技术中通常采取各种措施来减少水的影响，以防止水溶液中生物样品的信息被掩盖。该研究设计了两种可利用透射式太赫兹时域光谱(THz-TDS)系统检测的夹心式微流控芯片，通过减小THz与水的作用距离来减少水对THz的吸收，从而达到高透过率的目的。微流控芯片采用环烯烃共聚物(Zeonor 1420R)作为基片和盖片，聚二甲基硅氧烷(PDMS)作为沟道夹层，利用THz-TDS系统对该芯片进行了测试，测得该芯片在0.2～2.6 THz频率范围内的透过率可以达到80％以上。在微流控芯片中分别加入去离子水、1,2-丙二醇以及二者在不同体积比下的混合溶液，并测量了它们的透射谱。结果表明，不同比例溶液的THz光谱明显不同，说明该芯片在测量液态样品方面的可行性。此外，用该芯片分别研究了不同浓度的氯化钾和碘化钾溶液，发现氯化钾溶液随着浓度的增加THz透过率减弱，而碘化钾溶液则相反。初步认为，电解质改变了水溶液中的氢键密度，从而导致溶液对THz吸收的改变。

Sandwich Terahertz Microfluidic Chip

The vibrational and rotational model of many biological macromolecules fall in the THz range, so THz can be used for the qualitative identification of samples. It is well known that the activity of most biomolecules can be expressed in aqueous solution. However, water, as a polar substance, has a strong absorption to THz. Therefore, many measures are adopted to reduce the impact of water for getting more information of biological samples in liquid environment. In this paper, we designed two kinds of PDMS-based sandwich microfluidic chips, which couldreduce the absorption of THz by means of micro channel. Thereforea higher THz transmission of sampleswas achieved through the terahertz time-domain spectroscopy (THz-TDS) system. The material of Zeonor 1420r wasused as substrate and cover plate, and the PDMS as channel interlayer. The transmission of the empty microfluidic chip is more than 80% in the range of 0.2～2.6 THz by THz-TDS system. Then the THz spectra of deionized water and 1,2-propanediol with different concentrations in the microfluidic chip weremeasured, respectively. The results indicatethat the THz transmission of mixtures with different volume ratios has obvious difference. The feasibility of the chip to measure liquid samples has beenproved. In addition, the solutions of potassium chloride and potassium iodide with different concentrations were detected by using the microfluidic chip, and the results show that the transmittance of THz decreases with the increase of the concentration of potassium chloride solution, while the potassium iodide solution has the reverse result. It is found that the electrolyte changes the hydrogen bond density in the aqueous solution, which leads to the change of THz absorption in solution.