Terahertz circular polarization sensing for protein denaturation based on a twisted dual-layer metasurface

Protein denaturation has very important research value in nutrition, biomedicine, and the food industry, which is caused by the changes in the molecular structure of the protein. Since the collective vibrational and torsional modes of protein molecules are within the terahertz (THz) frequency range, THz spectroscopy can characterize the protein denaturation with several advantages of non-contact, label-free, real-time, and non-destructive. Therefore, we proposed a reflective THz time-domain polarization spectroscopy sensing method, and use a flexible twisted dual-layer metasurface film as a sensor to realize the thermal denaturation sensing, concentration sensing, and types identification of protein aqueous solutions. The experiment tested three proteins (bovine serum albumin, whey protein, and ovalbumin), and the results show that: for the thermal denaturation sensing, its detection sensitivity can reach 6.30 dB/% and the detection accuracy is 0.77%; for the concentration sensing, the detection sensitivity and detection accuracy reach 52.9 dB.mL/g and 3.6.10(-5) g/mL, respectively; in addition, different protein types can be distinguished by the difference of the circular polarization spectra. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Researchers proposed a sensing method using THz spectroscopy to characterize protein denaturation, which can achieve thermal denaturation sensing, concentration sensing, and type identification with high detection sensitivity and accuracy.