The vibrational and rotational energy levels of many biomolecules are in the terahertz band, so terahertz technology can be used to detect biomolecules. In addition, because the photon energy of terahertz wave is low and will not destroy biological samples in the detection process, terahertz technology has a very wide application prospect in the future research fields such as biochemical detection and information communication. As we all know, most biomolecules need to be in liquid environment to give full play to their biological activity. However, the hydrogen bond in aqueous solution will produce strong absorption in terahertz band. In addition, water molecules are polar molecules, and terahertz wave has strong resonance absorption to polar molecules, which makes it very difficult to detect active biomolecules in liquid environment by terahertz technology. Therefore, many research teams combine terahertz spectroscopy with microfluidic technology to reduce the impact of various factors on biomolecular detection. In this study, the THz microfluidic chip was prepared with cycloolefin copolymer (COC). The five potassium salt solutions in a constant electric field at different times were studied, which provided a basis for further strengthening the application of THz technology in biochemistry. What’s more, the electrolyte solution contains a large number of anions and cations, which will move under the action of electric field. And it provides technical support for the study of the dynamic characteristics of electrolyte solution by terahertz technology.
In recent years, with the continuous development of terahertz detection technology, the use of terahertz spectroscopy to study chemical samples has become one of the indispensable means in the field of biochemistry. However, the biological activity of most biomolecules can only be expressed in water solution, while water as polar molecules has strong absorption properties of THz wave. Therefore, it is difficult to study the activity of biological samples in water solution by using terahertz technology. In this study, a sandwich terahertz microfluidic chip with high transmission to terahertz wave was designed. The detection area of THz microfluidic chip is COC material, which is colorless and transparent, has no obvious absorption peak in THz frequency range, and has high THz wave transmission. The THz transmission of 2 mm thick COC can reach more than 90%. A valveless micropump was designed on the chip surface to realize automatic injection. The terahertz transmission spectra of distilled water, 0.9 mol/L NH4Cl, (NH4)2SO4, (NH4)2CO3 and CH3COONH4 were measured by combining the chip with terahertz technology in the frequency range of 0.1–0.7 THz. The experimental results show that at the same concentration, the THz spectra of different ammonium salt solutions are obviously different and the spectral intensity is lower than that of distilled water, which indicates that the hydration process of ions has an effect on the hydrogen bond between water molecules, and is reflected in the terahertz transmission spectrum.
Because the vibrational and rotational energy levels of many biomolecules are in the terahertz range, they can interact with terahertz. In addition, the photon energy of terahertz wave is very low, only meV level, which will not cause damage to the material, so terahertz technology can be used for non-destructive detection of biological molecules. As we all know, many biomolecules need to maintain their biological activity in aqueous solution, so it is of practical significance to study the biological characteristics in aqueous solution. The combination of terahertz and microfluidic technology can greatly reduce the absorption of liquid samples to terahertz, so it can detect more accurate signals. Therefore, terahertz time domain spectroscopy technology has a good application prospect in biological detection. The terahertz transmission characteristics of different sodium salts standing in electric field for different time are studied. Double layer terahertz microfluidic chips were prepared by using cycloolefin copolymer (COC) materials with high transmission rate for terahertz wave. The terahertz transmission characteristics of four kinds of sodium salts under the action of electric field were tested by using microfluidic chips with strong sealing performance. In order to avoid the influence of ionic impurities in aqueous solution, deionized water was used to prepare the solution. NaCl, CH3COONa, NaHCO3 and Na2CO3 electrolyte solutions with concentration of 0.9 mol/L are selected. The four solutions were injected into the microfluidic chip in turn, and then put into the external electric field device. The electric field treatment time is 0 min, 5 min, 10 min, 15 min and 20 min respectively. The transmission intensity is measured by terahertz time domain spectroscopy system every five minutes, and the corresponding spectrum can be obtained. The results show that with the increase of electric field time, the THz transmission intensity of the four sodium salt solutions increases.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.