Resonant Spin Polarization Transfer for Moving Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for hyperpolarizing nuclear spins in external molecules are inefficient, achieving low polarization rates and limited to small volumes, especially for particles in motion, due to the lack of effective schemes for transferring electron spin polarization and the adverse effects of molecular motion.
Innovation Solution
A method that utilizes resonant transfer of electron spin polarization to nuclear spins in particles moving near a polarisation structure, where the correlation time of the interaction between electron and nuclear spins is longer than the nuclear Larmor frequency, allowing for increased polarization transfer efficiency and applicability to a wide range of molecules, including proteins and nucleic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-resonant transfer (Overhauser effect) is used to polarize particles with molecular motion, then polarization can be achieved, but transfer efficiency is strongly limited by molecular motion correlation time
Solution Approach 1:
The patent changes the fundamental parameter of the transfer mechanism from non-resonant (Overhauser) to resonant transfer. By operating at resonance conditions where the electron spin transition frequency matches the nuclear Larmor frequency, the transfer efficiency is dramatically enhanced and becomes independent of molecular motion correlation time, resolving the contradiction between achieving polarization and maintaining efficiency with moving particles.
Solution Approach 2:
The resonant transfer mechanism provides universal applicability to particles of all sizes and types (small molecules, proteins, nucleic acids) regardless of their diffusion characteristics. This multi-functional approach eliminates the limitation imposed by molecular motion correlation time that plagues the Overhauser effect, enabling efficient polarization across diverse biological molecules.
2Quantity of substance
If direct polarisation of nuclear spins adsorbed on diamond surface is used, then some polarisation is achieved, but the polarisation rate is too low for substantial volumes (over 10,000 seconds for microliter)
Solution Approach 1:
The patent replaces the inefficient direct contact mechanism with a resonant electromagnetic interaction mechanism. By using microwave irradiation to drive electron spin transitions that are resonant with nuclear Larmor precession, the transfer of polarization occurs through electromagnetic fields rather than requiring direct adsorption and contact, dramatically accelerating the polarization rate to enable processing of substantial volumes in practical timeframes.
Solution Approach 2:
The patent employs periodic microwave irradiation at frequencies matched to the resonant conditions between electron spin transitions and nuclear Larmor precession. This periodic driving field continuously pumps polarization from electron spins to nuclear spins, maintaining high transfer rates that enable polarization of microliter volumes in minutes rather than hours or days.
3Measurement precision
If shallow nitrogen vacancy centres are used for sensing, then detection is achieved, but no clear scheme for polarising external nuclear spins was thought of
Solution Approach 1:
The patent introduces microwave irradiation as an intermediary that mediates the transfer of polarization from electron spins to external nuclear spins. The microwave field acts as the coupling mechanism that bridges the electron spin system in the diamond and the nuclear spin system in external molecules, providing a clear and implementable scheme that builds upon the existing detection capability with shallow NV centers.
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 significantly enhances the polarization rate of nuclear spins in moving particles, enabling the hyperpolarization of substantial volumes with reduced diffusion effects, and is suitable for various biological molecules, achieving high polarization levels at room temperature without the need for cryogenic cooling.
Implementation Method 1
electron spins in a particular kind of colour centre, a nitrogen vacancy centre, can be polarised optically independent of ambient temperature
Implementation Method 2
a polarisation of electron spins in the polarisation structure is resonantly transferred to the nuclear spins in the particles
Implementation Method 3
hyperpolarisation of nuclear spins by means of transferring the polarisation of electron spins to the nuclear spins
Implementation Method 4
the correlation time of the interaction between electron and nuclear spins is longer than the nuclear Larmor frequency
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of hyperpolarisation of nuclear spins in one or more particle(s) moving relatively to a polarisation structure, wherein a polarisation of electron spins in the polarisation structure is transferred to the nuclear spins in the particle(s), wherein for one or more of the moving particle(s) within 20 nm from a surface of the polarisation structure, the correlation time of the interaction with the nearest polarisation structure electron spin due to the molecular motion is larger than the inverse of the nuclear Larmor frequency; the electron spins in the polarisation structure are polarised above thermal equilibrium; and the polarisation transfer is performed resonantly.