Characterization of frequency-chirped dynamic nuclear polarization in rotating solids

Highly bioresistant, hydrophilic and rigidly linked trityl-nitroxide biradicals for cellular high-field dynamic nuclear polarization

“…For example, water-soluble dinitroxide-based biradicals (e.g., AMUPol, 27 AsymPolPOK 28,29 and M-TinyPols 30 ) and trityl-nitroxide (TN) hybrid biradicals (e.g., TEMTriPols 31 and NATriPols 22 ) have achieved relative DNP enhancements over 100 for [ 13 C, 15 N]-proline or 13 C-urea, and ∼30 for soluble proteins in the DNP juice at 18.8 T. In particular, we have recently demonstrated that the hydrophilic TN biradical SNAPol-1 32 has outstanding DNP performance with enhancement factors of 133 for [ 13 C, 15 N]-proline, 100 for soluble proteins and 61 for membrane proteins at 18.8 T with favourable T B times. While these dinitroxide-and TN-based PAs are well suited for cellular DNP applications in which samples are rapidly prepared and cooled to cryogenic temperatures, 10,32,33 their stability is compromised at ambient temperatures due to the cellular reducing environments. 11,23,24,26 Thus, the above mentioned third challenge has not been well addressed yet.…”

Polarizing agents for efficient high field DNP solid-state NMR spectroscopy under magic-angle spinning: from design principles to formulation strategies

“…28 The introduction of frequency-agile microwave sources allowing the manipulation of electron spins has brought new opportunities. [29][30][31][32] Several pulsed DNP methods have been proposed to more efficiently and selectively transfer electron spin polarization. [33][34][35][36][37][38] While these developments leave much hope for pulsed methods to become a cornerstone of DNP MAS NMR experiments in the future, such approaches are still relying on home-build equipment and their implementation at high magnetic eld remains to be demonstrated.…”

Cellular Applications of DNP Solid‐State NMR – State of the Art and a Look to the Future

“…The work discussed includes novel PA design/ delivery, [48][49][50][51]66] optimized sample preparation (e. g., use of selective isotope labelling [67] & cellular fractionation [52] ), application of novel pulse sequences including 1 H-detection, [68] chirped-DNP. [69] Lastly, we discuss the types of biological questions that can be answered by cellular DNP-ssNMR today and possibly in the future.…”