Study On Non-thermal Effects Of Terahertz Radiation On Alkaline Phosphatase Activity And Conformation

In recent years,with the wide application of terahertz technology in communica-tion,security,material detection and other fields,the biosafety of terahertz radiation on the human body has become an attracting and urgent problem to be studied.En-zymes play an indispensable role in human physiological activities.There are few studies on the interaction effects and behind mechanisms between terahertz radiation and alkaline phosphatase.Therefore,taking alkaline phosphatase as the research ob-ject,the aim of this research is to explore the biosafety of terahertz radiation(with a frequency of 0.1 THz and power density of 13 mW/cm~2)on alkaline phosphatase by studying the effects of terahertz radiation on alkaline phosphatase activity,and the in-teraction mechanisms between THz radiation and alkaline phosphatase in terms of changes in enzyme structures.The main contents and highlights of the thesis are as followed:1.In order to meet the needs of solution sample radiation experiments,the te-rahertz radiation system is designed and built,and the focus is to apply Marius's law to reduce the power of the terahertz polarized light,aiming to decrease the terahertz thermal effects.2.Studies on the interactions between terahertz radiation and alkaline phospha-tase activity are performed.Based on the p-nitrophenyl phosphate disodium method,we detect changes in alkaline phosphatase activity after enzymes being heated(28-45?)and being radiated by different-duration(0-40 min)THz wave.In compar-ison to the results of the enzymatic activity after heat treatment,it is inferred that short-term(ca.25 min)terahertz radiation reduces alkaline phosphatase activity by the non-thermal mechanism.And terahertz radiation for 20 minutes reduces the alka-line phosphatase activities in different concentrations(5 U/m L,7 U/m L,9 U/m L).3.In order to explore the behind mechanisms of terahertz non-thermal effects,the effects of terahertz radiation(20 min)on the alkaline phosphatase structures in different concentrations are detected by characterizing the ultraviolet absorption peak and fluorescence emission peak of the protein aromatic bases,the absorption peak of the peptide bond,and the terahertz absorption coefficient of the alkaline phosphatase solution,based on fluorescence spectroscopy,ultraviolet-visible absorption spectros-copy and terahertz time-domain spectroscopy.The results of the three spectra show that the conformations of the enzymes are altered after exposing to terahertz radiation,thus,it is deduced that terahertz radiation affects alkaline phosphatase activities by altering their structures.This work promotes the research about the interactions between 0.1 THz radia-tion and alkaline phosphatase,as well as shows a new direction for the biological ef-fects researches of terahertz radiation to enzymes.Besides,it lays the foundation for the wider application of terahertz technology considering biomedical safety.Moreover,the work shows the great potential of terahertz spectroscopy in the field of detecting alkaline phosphatase solution structure.