Porphyrins as Versatile, Aggregation-Tolerant, and Biocompatible Polarizing Agents for Triplet Dynamic Nuclear Polarization of Biomolecules

Tomoyuki Hamachi, Koki Nishimura, Hironori Kouno, Yusuke Kawashima, Kenichiro Tateishi, Tomohiro Uesaka, Nobuo Kimizuka, Nobuhiro Yanai

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)

    Abstract

    Triplet dynamic nuclear polarization (triplet-DNP) achieves nuclear spin polarization at moderate temperatures by using spin polarization of photoexcited triplet electrons. The applications of triplet-DNP for biomolecules have been hampered because acenes, the only polarizing agents used so far, tend to aggregate and lose their polarization in biomolecular matrices. Here, we report for the first time use of porphyrins as polarizing agents of triplet-DNP and propose a new concept of aggregation-tolerant polarizing agents. Sodium salts of tetrakis(4-carboxyphenyl)porphyrin (TCPPNa) can be dispersed in amorphous as well as crystalline biomolecular matrices, and importantly, it can generate polarized triplet electrons even in a slightly aggregated state. Triplet-DNP of crystalline erythritol containing slightly aggregated TCPPNa can achieve more than 120-fold signal enhancement. Because TCPPNa is also the first biocompatible triplet-DNP polarizing agent, this work provides a crucial step forward for the biological and medical applications of triplet-DNP.

    Original languageEnglish
    Pages (from-to)2645-2650
    Number of pages6
    JournalJournal of Physical Chemistry Letters
    Volume12
    Issue number10
    DOIs
    Publication statusPublished - Mar 18 2021

    All Science Journal Classification (ASJC) codes

    • Materials Science(all)
    • Physical and Theoretical Chemistry

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