Dynamic nuclear polarization enhanced nuclear magnetic resonance of water under ambient conditions

Abstract

A method and apparatus are provided for treating hydrated material in a fluid that contains water in which a stable nitroxide is attached to the hydrated material. A dynamic nuclear polarization process (DNP) is conducted on the hydrated material whereby to hyperpolarize the water. A polarization cell contains the hydrated material to obtain hyperpolarized water free from the nitroxide. The dynamic nuclear polarization process is conducted using components comprising a tunable, solid state high power X-band driver and an X-band resonator for microwave transmission to the hydrated material. The components can also include a radio-frequency nuclear magnetic resonance probe, a permanent magnet formed to receive the hydrated material, a portable nuclear magnetic resonance spectrometer, and an electron spin resonance detector. The components can be sized to be portable, and include electrical input and output and a lap-size hard-case with access to the electrical input and output.

1 . A method for treating hydrated material in a fluid that contains water in which a stable nitroxide radical spin label is attached to the hydrated material, comprising conducting a dynamic nuclear polarization process on the hydrated material whereby to hyperpolarize the water under ambient conditions. 
     
     
         2 . The method of  claim 1  in which the dynamic nuclear polarization process is conducted in a polarization cell (i.e. an ESR cavity of some kind) that contains the hydrated material wherein the hyperpolarized water is obtained, whereby the nitroxide radical is not freely dissolved in water, but attached to the hydrated material through covalent bonds. 
     
     
         3 . The method of  claim 2  in which the hydrated material in the polarization cell is agarose material and the nitroxide radical is a derivative of 2,2,6,6-tetramethypiperidine 1-oxyl. 
     
     
         4 . The method of  claim 3  in which the agarose material is sepharose. 
     
     
         5 . The method of  claim 2  in which the hydrated material is selected from hydrogel, tentagel, sephadex or modifications of agarose materials. 
     
     
         6 . The method of  claim 2  in which the nitroxide radical are other stable nitroxide spin labels other than derivatives of 2,2,6,6-tetramethypiperidine 1-oxyl. 
     
     
         7 . The method of  claim 2  in which the hyperpolarized water is created in continuous flow under ambient conditions. 
     
     
         8 . The method of  claim 2  in which the hyperpolarized water is free of nitroxides. 
     
     
         9 . The method of  claim 8  in which the hyperpolarized water free of nitroxides, in a pure form or mixed into isotonic saline solution or plasma, is intravenously injected into a living subject with the purpose of obtaining magnetic resonance images of blood flow with enhanced contrast. 
     
     
         10 . The method of  claim 8  in which the hyperpolarized water free of nitroxides, in a pure form or mixed in isotonic saline solution or plasma, is injected into the carotid artery of a living subject with the purpose of obtaining magnetic resonance images of blood flow with enhanced contrast. 
     
     
         11 . The method of  claim 1  for the selective characterization of local water associated with the hydrated material suspended in bulk water, the local water having a  1 H NMR signature under the application of the dynamic nuclear polarization process, comprising:
 covalently attaching nitroxide radicals to targeted sites of the hydrated material to form a functionalized molecule or material that is dissolved in or suspended in water whereby to form spin labeled molecules or materials; and 
 using the dynamic nuclear polarization process to amplify only the  1 H NMR signal of the local environment of the nitroxide spin label within roughly 10 Å distance. 
 
     
     
         12 . The method of  claim 2  in which the dynamic nuclear polarization process amplifies the  1 H NMR signal via electron spins residing on the spin labeled molecules wherein the electrons possess greater than 600 fold higher spin polarization compared to  1 H nuclei. 
     
     
         13 . The method of  claim 2  in which the hydrated material is a single molecule or an assembly of molecules, whereby the material can be composed of peptides, proteins, lipid molecules, amphiphilic surfactants, polymers or a mixture of such molecules. 
     
     
         14 . The method of  claim 2  in which the analysis of the dynamic nuclear polarization performed on hydrated molecules or materials that are specifically spin labeled at targeted sites yield local dynamic parameters, such as the translational correlation times of the nitroxide and water that is in dipolar interaction with the nitroxide, the local diffusion coefficient of water within roughly 10 Å distance of the spin label, the distance of closest approach between the unpaired electron of the nitroxide and the  1 H nucleus of water. 
     
     
         15 . The method of  claim 1  in which dynamic nuclear polarization process is conducted using components comprising a tunable, solid state high power X-band driver and an X-band resonator for microwave transmission to the hydrated material. 
     
     
         16 . The method of  claim 15  in which the components include:
 a radio-frequency nuclear magnetic resonance probe; 
 a portable magnet that contains the hydrated material; 
 a portable nuclear magnetic resonance spectrometer; and 
 an electron spin resonance detector. 
 
     
     
         17 . The method of  claim 16  in which the electron spin resonance detector has direct electron spin resonance detection capability. 
     
     
         18 . An x-band device for solution state dynamic nuclear polarization of a hydrated material, comprising the components:
 a tunable, solid state high power X-band driver; and   an X-band resonator for microwave transmission to the hydrated material.   
     
     
         19 . The device of  claim 18  in which the components include:
 a radio-frequency nuclear magnetic resonance probe; 
 a portable magnet that contains the hydrated material; 
 a portable nuclear magnetic resonance spectrometer; and 
 an electron spin resonance detector. 
 
     
     
         20 . The device of  claim 19  in which the electron spin resonance detector has direct electron spin resonance detection capability. 
     
     
         21 . The device of  claim 19  in which the components are sized to enable the device to be portable. 
     
     
         22 . The device of  claim 21  including electrical input and output and including a lap-size hard-case with access to the electrical input and output in which the components are packaged. 
     
     
         23 . An x-band device for solution state dynamic nuclear polarization of a sample, comprising the components:
 a tunable, solid state high-power X-band driver;   a portable magnet that contains the hydrated material;   an X-band resonator for microwave transmission to the hydrated material located in the magnet;   a radio-frequency nuclear magnetic resonance probe;   a portable electron spin resonance detector having   a portable nuclear magnetic resonance spectrometer;   an electron spin resonance detector having direct electron spin resonance detection capability;   electrical input and output; and   a lap-size hard-case with access to the electrical input and output in which the components are packaged.