A Primary Study On Transgenic Protein Cry1Ab By Terahertz Time-domain Spectroscopy Technology

In this paper, the terahertz time-domain spectroscopy was used to determine the transgenic protein CrylAb. The development situation of genetically modified (GM) crops, the risk as well as the regulatory situation was introduced, and routine detection methods of GM ingredients were also introduced. The development of terahertz technology and the application of terahertz technology in the field of protein detection were expounded. Then the preparation of samples, spectra collection method, and data processing methods was stated. The detection effect of binary mixture of transgenic protein CrylAb powder with the ultra-high molecular weight polyethylene using terahertz time-domain spectroscopy was discussed as well as the testing effect of the transgenic protein solution. Furthermore, terahertz detection on immune response of genetically modified protein and the antibody on the modified glass slide was studied.The main research results and conclusions are as follows:(1) Liquid experimental results showed that there were no significant differences between the terahertz spectra of transgenic CrylAb protein solution of six different concentrations with of solvent (PBS) in0.1-2.0THz. This result may come from high water absorption. Therefore, it had some limitations to detect transgenic CrylAb protein of solution state by terahertz spectroscopy.(2) The results of binary mixture pellet of transgenic protein Cry1Ab with PE showed that:Transgenic protein CrylAb has no characteristic absorption peak in the range of1.6-2.4THz. This result accords with the terahertz absorption law of protein. But in the frequency range, the terahertz absorption coefficient of the samples with high concentration increased as the frequency increases, while the terahertz absorption coefficients change of samples with low concentration was quite gentle.The variance analysis results of first four principal components showed that significant differences of difference concentrations mainly came from PCI (Principle Component1) score. No significant differences showed between low concentration samples (concentration2%,1%and0%), while there were significant differences between the high concentration samples (concentration of10%,10%and5%of the sample) with the pure PE samples (concentration0%). But other PCs showed no obvious regularity. Discriminant analysis results show that this method can accurately distinguish the difference concentrations between samples, the accuracy was96.3%, misclassification only occurs when the concentration was low. At2.356THz, correlation coefficient between absorption coefficient and the concentration reached maximum value of0.973, single variable regression method showed good linear relationship between the absorption coefficient and the concentration under this frequency, the decision value of the fitted curve coefficient (R2) was0.934.(3) The results of terahertz detection on immune response of genetically modified protein and the antibody on the modified glass slide showed that the method has yet to realize the detection of the transgenic protein Cryl Ab. And this method needs further improvement.