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Characterization of a Bio‐sourced, Fluorescent, Ratiometric pH Indicator with Alkaline pK a
Author(s) -
Alheety Samar,
Valenti Domenic,
Mujumdar Nirvani,
Ellis Nakita,
Campiglia Andres D.,
Harper James K.,
Heider Emily C.
Publication year - 2020
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13299
Subject(s) - fluorescence , fluorophore , chemistry , raw material , characterization (materials science) , natural product , photochemistry , nanotechnology , organic chemistry , materials science , physics , quantum mechanics
Utilizing organisms as sources of fluorophores relieves the demand for petroleum feedstock in organic synthesis of fluorescent products, and endophytic fungi provide a promising vein for natural fluorescent products. We report the characterization of a pH‐responsive fluorophore from an endophytic fungus isolated from sand pine. The endogenous fluorescence of the live organism was measured using fluorescence microscopy. Computational interpretation of the spectra was accomplished with time‐dependent density functional theory methods. The combined use of experimental and theoretically predicted spectra revealed the pH equilibria and photoexcited tautomerization of the natural product, 5‐methylmellein. This product shows promise both as a stand‐alone pH‐indicating fluorophore, with alkaline pK a , and as "green" feedstock for synthesis of custom fluorophores.