Open AccessSquaraine Dyes: Molecular Design for Different Applications and Remaining Challenges
Author(s) -
Kristina Ilina,
William M. MacCuaig,
Matthew Laramie,
Jannatun N. Jeouty,
Lacey R. McNally,
Maged Henary
Publication year - 2019
Publication title -
bioconjugate chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.279
H-Index - 172
eISSN - 1520-4812
pISSN - 1043-1802
DOI - 10.1021/acs.bioconjchem.9b00482
Subject(s) - chemistry , biomolecule , fluorescence , nanotechnology , photothermal therapy , photochemistry , combinatorial chemistry , biochemistry , materials science , physics , quantum mechanics
Squaraine dyes are a class of organic dyes with strong and narrow absorption bands in the near-infrared. Despite high molar absorptivities and fluorescence quantum yields, these dyes have been less explored than other dye scaffolds due to their susceptibility to nucleophilic attack. Recent strategies in probe design including encapsulation, conjugation to biomolecules, and new synthetic modifications have seen squaraine dyes emerging into the forefront of biomedical imaging and other applications. Herein, we provide a concise overview of (1) the synthesis of symmetrical and unsymmetrical squaraine dyes, (2) the relationship between structure and photophysical properties of squaraine dyes, and (3) current applications of squaraine dyes in the literature. Given the recent successes at overcoming the limitations of squaraine dyes, they show high potential in biological imaging, in photodynamic and photothermal therapies, and as molecular sensors.