Ring-Fused Firefly Luciferins: Expanded Palette of Near-Infrared Emitting Bioluminescent Substrates

Yuma Ikeda, Takahiro Nomoto, Yuki Hiruta, Nobuhiro Nishiyama, Daniel Citterio

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Firefly bioluminescence is broadly applied as a noninvasive imaging modality in the biomedical research field. One limitation in firefly bioluminescence imaging is the limited variety of luciferins emitting in the near-infrared (NIR) region (650-900 nm), where tissue penetration is high. Herein, we describe a series of structure-inherent NIR emitting firefly luciferin analogues, NIRLucs, designed through a ring fusion strategy. This strategy resulted in pH-independent structure-inherent NIR emission with a native firefly luciferase, which was theoretically supported by quantum chemical calculations of the oxidized form of each luciferin. When applied to cells, NIRLucs displayed dose-independent improved NIR emission even at low concentrations where the native d-luciferin substrate does not emit. Additionally, excellent blood retention and brighter photon flux (7-fold overall, 16-fold in the NIR spectral range) than in the case of d-luciferin have been observed with one of the NIRLucs in mice bearing subcutaneous tumors. We believe that these synthetic luciferins provide a solution to the longstanding limitation in the variety of NIR emitting luciferins and pave the way to the further development of NIR bioluminescence imaging platforms.

Original languageEnglish
Pages (from-to)4235-4243
Number of pages9
JournalAnalytical Chemistry
Issue number6
Publication statusPublished - 2020 Mar 17

ASJC Scopus subject areas

  • Analytical Chemistry


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