The hottest new technology for intracellular merca

2022-09-29
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A new technology for intracellular mercaptan detection - hyperpolarized 129Xe magnetic resonance

Zhou Xin's research group at Wuhan Institute of physics and mathematics, Chinese Academy of Sciences designed and synthesized a mercaptan responsive 129Xe magnetic resonance/fluorescence dual-mode ultra sensitive molecular probe on the independently developed hyperpolarized 129Xe magnetic resonance instrument, and took the disulfide bond as the response site of mercaptan, realizing the magnetic resonance detection sensitivity of mercaptan in the order of picmole (m)

mercaptans such as glutathione (GSH), cysteine (Cys), homocysteine (Hcy) play an important role in cell metabolism. In cancer, Alzheimer's disease, Parkinson's disease and other diseases, the content of intracellular mercaptan is higher than normal. Therefore, it is of great significance to detect the intracellular sulfur activity assay and the ultra sensitive detection of alcohol. At present, the most commonly used method to detect intracellular mercaptan is fluorescence method, but the tissue penetration of fluorescence is relatively low. Magnetic resonance technology has the advantages of non-destructive, immediate drainage detection, no radioactivity, no tissue penetration depth limitation, but the current traditional magnetic resonance technology has low sensitivity. Super, that is, the earliest wood plastic composite new material polarization 129Xe magnetic resonance is a new magnetic resonance molecular imaging technology. Compared with the needs of phase high-frequency fatigue testing machine, it also begins to show an upward trend. Under the same conditions, the sensitivity of traditional magnetic resonance is enhanced by more than 50000 times, and at the same time, it has the above advantages of traditional magnetic resonance

recently, the Zhou Xin research group of Wuhan Institute of physics and mathematics, Chinese Academy of Sciences, designed and synthesized a thiol responsive 129Xe magnetic resonance/fluorescence dual-mode ultra sensitive molecular probe on the self-developed hyperpolarized 129Xe magnetic resonance instrument, and took the disulfide bond as the response site of thiol, realizing the magnetic resonance detection sensitivity of thiol picomole (m). Hyperpolarized 129Xe magnetic resonance not only provides a new ultra sensitive technology for intracellular mercaptan detection, but also takes an important step for the next step of in vivo application

figure 1.schematic diagram of 129Xe magnetic resonance/fluorescence dual-mode probe molecule reacting with mercaptan in cells

in solution, after the hyperpolarized 129Xe magnetic resonance and fluorescence dual-mode molecular probe reacting with mercaptan, the disulfide bond breaks, and at the same time, the part connected with the fluorescent group naphthalimide will undergo intramolecular cyclization reaction, which will enhance the fluorescence. Due to the sensitivity of hyperpolarized 129Xe to the chemical environment, when the disulfide bond of the probe molecule breaks, it also causes the change of 129Xe magnetic resonance signal in the supramolecular cage. Therefore, they can use fluorescence and 129Xe magnetic resonance to carry out the dual-mode ultra sensitive detection of mercaptan

Figure 2 Fluorescence spectra and hyperpolarized 129Xe magnetic resonance spectra after the reaction of hyperpolarized 129Xe magnetic resonance and fluorescence dual-mode probe molecules with GSH; (a) Fluorescence spectra of probe molecules after reaction with different stoichiometric GSH; (b) Hyperpolarized 129Xe magnetic resonance spectrum after the probe molecule reacts with different stoichiometric GSH

in cells, the hyperpolarized 129Xe magnetic resonance and fluorescence dual-mode probe molecule also showed good response to mercaptan. Strong green fluorescence appears when the probe molecules enter the cell. When treated with mercaptan inhibitor NEM, the probe molecules are introduced into the cell, and the fluorescence of the probe molecules in the cell is significantly weakened

Figure 3 Laser confocal after the probe molecule enters the cell

the researchers studied the hyperpolarized 129Xe magnetic resonance spectrum after the probe molecule enters the cell in combination with the magnetic resonance technology of chemical exchange saturation transfer (CEST). When the probe molecules were introduced into the cells, a strong CEST effect was observed in the cells; When the cells were first treated with NEM, and then the probe molecules were introduced into the cells, the effect of CEST in the cells was significantly weakened. This test result is highly consistent with the fluorescence method, indicating that the sensitivity of hyperpolarized 129Xe magnetic resonance in detecting intracellular mercaptans is almost the same as that of fluorescence

Figure 4 CEST magnetic resonance spectrum of hyperpolarized 129Xe magnetic resonance and fluorescence dual-mode probe molecules after entering cells

this research achievement was recently published on Analytical Chemistry under the American Chemical Society. Guo Xini, associate researcher of Wuhan Institute of physics and mathematics, Chinese Academy of Sciences, and Dr. Zeng Qingbin are the co first authors. The research was supported by the major scientific research instrument development project of the National Natural Science Foundation of China, the outstanding young scholars fund project and the Chinese Academy of Sciences

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