Enhancement Of Nuclear Magnetic Resonance Spectroscopy And Imaging Resolution And Their Application In Complex Environments

Nuclear magnetic resonance has been widely used in many fields due to its noninvasive advantages.However,due to the chemical and spatiotemporal environment,the resolution requirements for practical applications cannot be met in many cases.Therefore,improving the resolution of nuclear magnetic resonance technology by various means has always been an urgent problem for relevant researchers.In this study,from the perspectives of nuclear magnetic resonance spectroscopy and magnetic resonance imaging,the resolution of nuclear magnetic resonance was improved and the application of high-resolution nuclear magnetic resonance was realized,and the structure and properties of samples were explored from multiple perspectives.In nuclear magnetic resonance spectroscopy,the homogeneity of the sample and the homogeneity of the magnetic field it experiences determine the resolution of the spectrogram.We choose the phospholipid hydrolysis process as the research system.Through macro characterization,dynamic light scattering,nuclear magnetic resonance methods to verify the effectiveness of the system of space-time inhomogeneity,the characteristics of the uneven space-time has been limiting its reaction kinetics research.To this end,we have made some debugging and optimization on the basis of the intermolecular double quantum coherence sequence,breaking through the limitation of the complex environment on the resolution of NMR spectra,and successfully realized the acquisition of high-resolution proton spectra of the phospholipid hydrolysis system.The change of characteristic peaks in the whole hydrolysis process was quantitatively analyzed,and the reaction kinetics analysis of the phospholipid hydrolysis process was finally completed.In this work,the detailed information of the hydrolysis process of phospholipids is successfully presented.It also provides an effective idea for identifying the composition of complex natural products and tracking their changes in real time.In the case of magnetic resonance imaging,resolution limits the spatial geometric distance of recognizable neighboring objects.The development of new magnetic resonance contrast agents to enhance the signal intensity of the image will have a significant effect on the improvement of image resolution.To this end,we developed three different magnetic resonance contrast agents:(1)Using laser ablation liquid,laser induced liquefaction and ion etching process preparation of Mn3O4/PtOx nanoparticles:Its longitudinal relaxation is four times higher than commercial Gd-DTPA.(2)Magnetosome-like magnetic nanoparticles with single domain were synthesized by thermal decomposition using the constructed magnetosome-like biomimetic nanoreactor,which had good magnetotactic targeting property and significantly improved the signal-to-noise ratio of magnetic resonance images in the targeted region.(3)By combined the advantage of inorganic nanometer material and protein carrier successfully designed the bovine serum albumin magnetite nanoparticles,which can effectively improve the T1-weighted magnetic resonance image signal-to-noise ratio.We also verified the in vivo imaging effects of the above-mentioned contrast agents.The results showed that the above-mentioned contrast agents can improve the signalto-noise ratio of the image,thereby indirectly achieving the goal of shrinking voxels and improving image resolution.However,we found that this way of indirectly reducing voxels and improving image resolution by increasing image signal-to-noise ratio is difficult to meet our imaging needs for the subtle structures of some organisms,such as capillaries.To this end,we designed and fabricated a micro imaging coil for Bruker magnetic resonance imaging spectrometer.The feasibility of the coil is verified by simulating the Sparameter and electromagnetic field.Experimental results show that the signal-to-noise ratio of the proposed coil in aqueous samples is 6.59 times higher than that of commercial magnetic resonance imaging coils.The magnetic resonance imaging of mammals also show that the spatial resolution of the micro imaging coil has been significantly improved compared with commercial magnetic resonance imaging coils.It not only provides an excellent detection method for exploring the fine structure of the sample,but also provides a good example for further improving the spatial resolution of the large-cavity magnetic resonance imaging spectrometer.This work has improved the resolution from the perspectives of nuclear magnetic resonance spectroscopy and magnetic resonance imaging,and explored the structure and properties of samples from multiple angles.It not only effectively broadens the application range of nuclear magnetic resonance,but also provides a good template and idea for further improving the resolution of nuclear magnetic resonance.