Lead


Lay summary
The main advantage of nuclear magnetic resonance (NMR) lies in its ability to differentiate between molecules or between different sites in a molecule based on their chemical environment. Its main drawback is the limited sensitivity, typically NMR measurements needing concentrations on the order of 10-3 M in half-ml volumes for liquid-state NMR and app. 10 mg of powder for solid-state NMR. These concentrations are often hard (or expensive) to obtain for samples of interest. Moreover, biologically relevant reactions occur at much lower concentrations.The sensitivity of NMR may be enhanced if nuclear spins are coupled to unpaired electron spins, which have a much higher polarization. This can be achieved in a sample where a paramagnetic radical is mixed with the molecule of interest via the effect known as Dynamic Nuclear Polarization (DNP). We aim to apply this method to both liquid and solid-state NMR, in the latter case namely for the study spin-1 nuclei such as nitrogen-14, which is present in most biomolecules in natural abundance.The short lifetimes of spin order in comparison to the characteristic time of biological reactions are a serious barrier in the way of applications of hyperpolarized magnetic resonance to liquid state NMR. The magnetization of nuclei with low gyromagnetic ratios has low relaxation rate constants, but the sensitivity for detection of such nuclei is limited. We plan to show that long lifetimes of enhanced magnetization may be obtained on the sensitive proton spins.