溶解动态Se核的核极化77Se核
Eul Hyun Suh1, James Ratnakar1, Jaspal Singh1
1Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390.
Analysis & sensing
|October 6, 2025
概括
溶解动态核极化 (DNP) 核磁共振可以增强在无缩的情况下在液态状态下对-77 (77Se) 的信号. 信号增强在很大程度上取决于化合物的分子对称性,其中一些显示出显著的增强.
科学领域:
- 核磁共振 (NMR) 光谱学 核磁共振 (NMR) 光谱学
- 化学 化学 化学
- 生物物理化学 生物物理化学
背景情况:
- -77 (77Se) NMR对于表征含分子,包括蛋白质非常有价值.
- 在生物样本中检测77Se是很困难的,因为它的灵敏度低,自然丰富 (7.6%).
- 为了有效检测77Se,通常需要进行丰富,这对生物研究构成了挑战.
研究的目的:
- 通过溶解动态核极化 (DNP) 核磁共振 (NMR) 在液态中增强77Se核磁共振信号的可行性.
- 为了确定DNP是否可以规避生物样本中77Se的同位素丰富的需要.
- 评估分子对称性对77Se信号增强通过DNP的影响.
主要方法:
- 溶解动态核极化 (DNP) 的NMR实验是在三种化合物上进行的:酸,酸和酸.
- 这些化合物因其不同的分子对称性而被选中.
- 实验使用商业可用的DNP NMR硬件,场强度为9.4 T.
主要成果:
- 溶解DNP NMR成功增强了77Se信号,证明了它的可行性.
- 观察到显著的信号增强:酸盐为1368倍,酸盐为125倍.
- 对于单囊素,没有取得显著的增强,突出显示了对分子对称性的强烈依赖.
- 对于77Se,占主导地位的自旋格子放松机制,化学转移异构性,受到分子对称性的影响.
结论:
- 使用溶解DNP的77SeNMR信号增强可以用标准设备实现.
- 信号增强的程度严重依赖于化合物的分子对称性.
- 这种DNP方法提供了一种潜在的方法,可以在没有同位素丰富的情况下改善在生物系统中的77Se检测.
相关概念视频
Nuclear Overhauser Enhancement (NOE)
1.4K
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...
1.4K
Atomic Nuclei: Nuclear Relaxation Processes
1.2K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
1.2K
Nuclear Stability
22.9K
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together...
To hold positively charged protons together...
22.9K
Atomic Nuclei: Nuclear Spin State Population Distribution
2.3K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
2.3K
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
998
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
998
Atomic Nuclei: Nuclear Spin State Overview
1.9K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.9K


