Aromatic Compound 13C Relaxation Time Extension
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Solution Overview
Problem
Current DNP technology for MRI is limited by the short relaxation time of 13C nuclei, which restricts its application for long-term observations and makes it unsuitable for detailed metabolic studies.
Innovation Solution
Development of an aromatic compound with two adjacent carbon atoms as 13C, where other atoms bonded to these carbon atoms have a spin quantum number of 0, and a hydrogen atom bonded to the 13C nucleus is substituted with a deuterium atom, enhancing the relaxation time of the 13C nucleus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DNP method is used to improve polarization rate, then measurement sensitivity is improved by several digits, but polarization is lost in a few seconds to a few tens of seconds due to magnetic field modulation by molecular motion
Solution Approach 1:
The patent changes the chemical structure parameters of the aromatic compound by introducing specific substituents (deuterium atoms, groups with spin-0 nuclei) to modify the relaxation properties of the 13C nuclei, thereby extending polarization lifetime while maintaining measurement sensitivity
Solution Approach 2:
The patent creates a composite nuclear spin system involving 13C nuclei coupled with spin-0 nuclei (deuterium, 12C, 16O, etc.), where the spin-0 nuclei provide a protective effect that extends the singlet state lifetime without interfering with the 13C NMR signal detection
2Ease of operation
If conventional aromatic compounds are used for DNP, then NMR spectroscopy and MRI can be performed, but the relaxation time of 13C nuclei is too short for long-term observations and detailed metabolic studies
Solution Approach 1:
The patent systematically varies the substituent parameters on the aromatic ring (different spin-0 groups at different positions) to optimize the relaxation time while maintaining the compound's suitability for NMR spectroscopy and MRI applications
Solution Approach 2:
The patent segments the molecular environment around the 13C nuclei by introducing specific substituents at different positions on the aromatic ring, creating distinct chemical environments that protect the 13C singlet state from relaxation while maintaining detectability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed aromatic compound significantly extends the relaxation time of the 13C nucleus, enabling longer polarization lifetimes and facilitating more extensive and accurate metabolic observations and imaging.
Implementation Method 1
it is known that a singlet state of the nearest-neighbor nucleus spin pair is a long-lived state with respect to this interaction
Implementation Method 2
A dynamic nuclear polarization (DNP) method is used as a method for improving the measurement sensitivity by improving the polarization rate by several digits
Implementation Method 3
the Zeeman energy of the nucleus spins is very low even under a strong magnetic field of several teslas (T) to several tens of teslas applied by a superconducting magnet
Data Source
Figure 1~2
Figure 3~4
AI summary
An aromatic compound is composed of a stable isotope, in which two adjacent carbon atoms are 13C, atomic nuclei of other atoms to which the two adjacent carbon atoms are bonded have a spin quantum number of 0, and a hydrogen atom which has a spin coupling constant and is bonded to the 13C nucleus through a carbon atom is substituted with a deuterium atom. In the aromatic compound, a relaxation time of a 13C nucleus excited by a DNP device is longer than that in the related art.