SABRE-SHEATH Hyperpolarization via Microtesla Magnetic Fields
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Solution Overview
Problem
Current methods for hyperpolarizing heteronuclei, such as 13C and 19F, are inefficient and require complex setups, with existing techniques like d-DNP being costly and difficult to scale, while PHIP is limited to specific molecular frameworks and SABRE efficiency is low due to quadrupolar nuclei interference.
Innovation Solution
The SABRE-SHEATH method involves combining parahydrogen, a catalyst, and a compound with a heteronucleus, applying a magnetic field of less than 50 μT to transfer spin order from parahydrogen to the heteronucleus, facilitating efficient hyperpolarization without RF irradiation, and utilizing isotopically enriched compounds to enhance polarization transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If d-DNP is used for hyperpolarization, then NMR signal enhancement is achieved, but cost and device complexity increase significantly
Solution Approach 1:
The patent uses an organometallic catalyst as an intermediary to mediate the interaction between parahydrogen and the substrate molecule. The catalyst enables spin order transfer from parahydrogen to the substrate through a reversible exchange mechanism, achieving hyperpolarization without requiring the complex infrastructure of d-DNP facilities.
Solution Approach 2:
The patent changes the magnetic field parameter from the high fields required by traditional NMR methods to low fields (5-7 mT) for the SABRE process. This parameter change enables the use of simpler, more scalable equipment while achieving the desired hyperpolarization effect through scalar couplings in the low-field regime.
2Measurement precision
If traditional PHIP is used, then hyperpolarization is achieved, but the method is limited to specific molecular frameworks with unsaturated bonds
Solution Approach 1:
The SABRE method provides a universal platform for hyperpolarizing diverse substrate molecules through reversible exchange with parahydrogen on an organometallic catalyst. The method works with various molecular frameworks including heteronuclei-containing compounds, extending the applicability beyond the limited unsaturated bond requirements of traditional PHIP.
3Measurement precision
If SABRE is used for heteronuclei hyperpolarization, then spin order transfer is achieved, but efficiency is reduced due to quadrupolar nuclei interference
Solution Approach 1:
The patent extracts or removes the harmful quadrupolar nuclei from the system by using substrates where the heteronucleus of interest is coupled to non-quadrupolar atoms (such as 15N instead of 14N). This elimination of quadrupolar interference restores efficient spin order transfer from parahydrogen to the heteronucleus through the organometallic catalyst.
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
This approach achieves significant nuclear spin polarization enhancements, up to 4.8% for 13C and 0.28% for 19F, enabling efficient biomedical imaging applications with scalable and cost-effective production of hyperpolarized contrast agents.
Implementation Method 1
applying a magnetic field with a strength of less than 50 μT to the complex, thereby transferring the spin order from the parahydrogen to the hyperpolarizable heteronucleus associated with the complex
Implementation Method 2
In low field (e.g., 5-7 mT), net spin order can be transferred from the para-H2 to the spins of the substrate via scalar couplings
Implementation Method 3
SABRE generally uses an organometallic catalyst to transiently co-locate para-H2 and the target substrate molecule in a low-symmetry complex in solution
Implementation Method 4
the plurality of molecules of the compound have been modified so as to isotopically enrich the other atom with the non-quadrupolar isotope
Data Source
AI summary
Provided are methods for nuclear spin polarization enhancement via signal amplification by reversible exchange at very low magnetic fields. The spin polarization is hyperpolarization of isotopically enriched heteronuclei by using a catalyst and parahydrogen to create a complex using iridium and applying magnetic fields in the microtesia range to transfer the spin order from parahydrogen to the complex.