Hyperpolarized water through dissolution dynamic nuclear polarization with UV-generated radicals.

Hyperpolarized water has emerged as a promising alternative to traditional contrast agents in MRI. Conventional methods rely on gadolinium-based compounds, which have limitations in tracking biochemical processes. While hyperpolarized water could provide insights into proton exchange and chemical reactions, achieving stable polarization remains a challenge. Radicals are essential for DNP, but they also cause rapid relaxation of the polarized state. Prior research has shown that water protons can be hyperpolarized, but maintaining this state during transfer is difficult. This gap motivated researchers to explore alternative radical generation methods. UV-generated radicals offer a new approach to dDNP. That uncertainty drove the development of this novel technique. No prior work had resolved the issue of radical-induced relaxation during transfer. This study addresses that limitation.

The aim of this study is to demonstrate a novel dDNP method using UV-generated radicals for hyperpolarizing water protons. The specific problem is the rapid relaxation caused by radicals during transfer to NMR or MRI systems. The motivation is to improve the feasibility of hyperpolarized water for clinical and research applications. By using UV-generated radicals, the researchers aim to reduce relaxation effects. This approach could enhance the stability of hyperpolarized states during transfer. The study also seeks to validate the method by acquiring a nitrogen spectrum from urea. This validation confirms magnetization transfer from water to nitrogen nuclei. The researchers propose that this method could expand the use of hyperpolarized water in MRI.

The study employs dissolution Dynamic Nuclear Polarization (dDNP) with UV-generated radicals. Pure water samples were used to achieve hyperpolarization. UV light was applied to generate labile radicals in situ. These radicals facilitated the polarization of water protons. The dissolution process was carefully controlled to minimize relaxation. A single scan was used to acquire a ¹⁵N spectrum from urea. The magnetization transfer from water to nitrogen nuclei was spontaneous. The method was tested under conditions mimicking clinical and research settings.

The researchers achieved water proton magnetizations equivalent to a 10,000 T field at room temperature. This level of polarization was obtained using UV-generated radicals. The radicals were labile, which reduced their impact on relaxation. A ¹⁵N spectrum from natural abundance urea was successfully acquired. The spectrum was obtained with a single scan, demonstrating efficiency. The magnetization transfer from water to nitrogen nuclei was spontaneous. These results suggest the method's potential for NMR and MRI applications. The findings support the use of UV-generated radicals in dDNP.

The authors propose that UV-generated radicals can effectively hyperpolarize water protons. This method reduces radical-induced relaxation during transfer. The study demonstrates the feasibility of this approach in practice. The acquired ¹⁵N spectrum confirms magnetization transfer. These results suggest the method could be useful in MRI and NMR studies. The researchers suggest that this technique may provide an alternative to Gd-based contrast agents. The findings may support further development of dDNP for clinical use. The authors suggest that this method could expand the applications of hyperpolarized water.