DNP-enhanced Tissue HRMAS MRS - Towards Measurements of Single-Cell Metabolomics

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DESCRIPTION (provided by applicant): The proposed research focuses on the development DNP-enhanced high-resolution magic-angle-spinning (HRMAS) magnetic resonance spectroscopy (MRS) to quantify cellular metabolities within intact prostate tissue. This will allow the study of micro-dissected pure pathological features, which is currently not possible due to the sensitivity limitations of the method. With DNP, the inherently small signal intensities in an NMR/MRS experiment can be drastically enhanced. In recent years, DNP has proven to be a robust method to increase signal intensities in NMR experiments in laboratories around the world and substantial progress has been made in adapting DNP for solution-state NMR spectroscopy. The enhancements available through DNP (> 80) are in Iarge contrast to the sensitivity gain that can be expected from a cryo-probe. However, since (human) tissue has the characteristics corresponding of solid and solution-state NMR samples, specific technology has to be developed to bring the advantage of DNP to HRMAS MRS for tissue studies. We propose to develop novel instrumentation and methodology for DNP-enhanced HRMAS experiments. The tissue sample will be polarized in-situ and the method allows for continuous signal acquisition. Since the sample characteristics is predominantly that of a solution sample, the Overhauser Effect (OE) will be used to polarize the sample. It is know that high-field OE experiments suffer from severe sample heating, therefore, we propose to use a variant of the OE that can reduce the amount of THz power the sample is exposed to by factor >250. While Phase I of this project is designed as a proof-of-concept study, we expect signal enhancements of >10 during Phase II of this proposal. The successful development of this technology will allow rapid proliferation of DNP-enhanced HRMAS MRS experiments to study micro-dissected pure pathological features, which will be of large interest to many projects funded by the U.S. National Institutes of Health.