Terahertz Spectroscopy Detection Technology Of Base Mutation DNA Molecule Based On Micro-nanostructures

Gene mutation detection is critical for many biomedical applications,as it is important for various analyses,especially those routinely employed in cancer research.Interest in label-free genetic diagnostic techniques have increased in recent years as a result.Terahertz spectroscopy employs radiations that lie between the microwave and infrared regions of the electromagnetic spectrum.The conformational changes of DNA molecules involve optical transitions within the THz range,readily providing information that is generally absent in optical,X-ray,and nuclear magnetic resonance spectroscopic techniques.THz radiation is known to be mild to biological systems.This is quite fortuitous,as the conformational information closely related to biological functions of biomolecules in cells is difficult to access with other techniques.In recent years,terahertz technology has already made a big push into the biomedical field.THz spectroscopy detection in the conformational changes of the active biomolecules has been restrained as the strong absorption of water in biological solutions.The perfect combination of micro-nano structures and terahertz technology took THz spectroscopy detection of active biomolecules a step further.The micro-nano structures reduces the absorption of water effectively and enhances the characteristic signals of biomolecules;Meanwhile it provides cell-like natural micro-environment for biomolecules and eliminates the terahertz signal changes caused by traditional molecular binding.In this report,we describe our recent successful attempt at label-free detection of base mutations on DNA molecules in aqueous solutions using Terahertz time-domain spectroscopy(THz-TDS)combined with micro-nano biosensor chips.The main research contents are as:(1)Micro-nanostructures were used to construct cell-like micro-environment limited system for biomolecules.Due to the terahertz spectral characteristics of biomolecules,the micro-nano structures were proposed to construct cell-like natural micro-environment limited system for biomolecules.Three kinds of terahertz micro-nano biosensor chips for liquid samples were described in detail,including terahertz microfluidics,terahertz resonance ring,terahertz attenuated total reflection microfluidics.The theoretical design,fabrication process and performance characterization of THz micro-nano biosensor chips for the above three liquid samples were discussed.The micro-nano structures were employed to realize the function that traditional terahertz biological detection technology can not achieve.That is to say,the real-time THz spectroscopy was used to detect biomolecules in cell-like liquid environment.Micro-nano structure was employed to enhance terahertz signal as a cross-scale bridge between terahertz wave and biomolecule,which breaks the technical barrier caused by strong absorption interference of aqueous solution,realizes conformation analysis and detection of active biomolecules,and provides theoretical guidance and technical means for life science,drug development and other major applications.(2)Terahertz spectroscopy experiment and molecular dynamics theory were mutually verified.Gene mutation is the base mutation of DNA molecule,so the base spectral analysis is the basis of gene mutation research.First of all,the feasibility of THz-TDS detection for DNA,RNA bases and rare bases was discussed.And then the four single-stranded oligonucleotides with 5-base mutation have been detected by THz spectroscopy with micro-nano biosensor chips.The advantages and disadvantages,and the THz spectroscopy detection results of three kinds of micro-nano biosensor chips were compared and analyzed.At the same time,the number of hydrogen bonds formed between the oligonucleotide and its surrounding water molecules was explored using molecular dynamics simulations,which explained and verified the conformational changes of DNA molecules caused by gene mutation.Our work underlies the feasibility of THz spectroscopy combined with micro-nano biosensor chips for marker-free detection of DNA.(3)The application of THz spectroscopy detection was explored in clinical diseases.In this study,the research objects were single base mutation oligonucleotides of sickle cell anemia and thrombocytopeniathe with important medical and biological significance,and the base repeat oligonucleotides of Huntington chorea typical case.THz-TDS detection combined with attenuated total reflection microfluidics was applied to biomedical diagnosis,which confirmed the potential value of the application of THz spectroscopy detection in clinical disease.