Coumarin-based Fluorescent Probes for Bioimaging: Recent Applications and Developments

Abstract

: Coumarin-based derivatives have easy modification and tunable properties and have been synthesized and applied in many areas including pro-drugs, biomedical materials, and chemical and biological sensing. In this review, recent advances of coumarin-based fluorescent probes for biosensing are reported for metal ion imaging. Metal detection in living cells will be highlighted with representative examples together with fluorescence response mechanisms such as photoinduced electron transfer (PET), intramolecular charge transfer (ICT), and fluorescence resonance energy transfer (FRET). Some future perspectives are also briefly mentioned.

Rational Design and Biological Application of Hybrid Fluorophores

“…[4][5][6][7] To date, many organic fluorophores have been developed, including the commonly used xanthenes (such as rhodamine and fluorescein), [8][9][10][11] cyanine, [12,13] BODIPY, [14,15] and coumarin. [16,17] However, they also have inherent limitations, such as a small Stokes shift, a low fluorescence quantum yield, and poor water solubility, which restrict their further applications. The photophysical properties of excellent fluorophores include: [18][19][20][21] 1) The emission wavelength is located in the nearinfrared (NIR) range to achieve enhanced tissue penetration depths for reduced damage during imaging, while also minimizing interference from organism self-fluorescence.…”

“…To date, many organic fluorophores have been developed, including the commonly used xanthenes (such as rhodamine and fluorescein), [8–11] cyanine, [12,13] BODIPY, [14,15] and coumarin [16,17] . However, they also have inherent limitations, such as a small Stokes shift, a low fluorescence quantum yield, and poor water solubility, which restrict their further applications.…”

Syntheses and Applications of Coumarin-Derived Fluorescent Probes for Real-Time Monitoring of NAD(P)H Dynamics in Living Cells across Diverse Chemical Environments

“…[9][10][11][12][13][14][15][16][17][18][19][20][21]23,24 Our probe formulations are based upon coumarins which are a large family of 2H-chromen-2-one-containing compounds that are widely used as fluorescent fluorophores due to their unique optical and chemical properties, including broad excitation and emission wavelengths, high quantum yield, chemical stability, low toxicity, and ease of modification. 25−29 As a result, coumarins are utilized as a desirable and ideal fluorophore platform for a wide range of applications, such as biological imaging, sensing, and diagnostics for cations, 30 anions, 27,29,31 pH, 32−34 NADH, 17 H 2 S, 27,29,31 cysteine, homocysteine, and glutathione (GSH), 27,29,31 cellular membranes, and reactive oxygen and nitrogen species. 27,29,31,35,36 The fluorescence of coumarin fluorophores has been tuned to longer emission regions by extending the π-conjugation at the 3-or 4-position through a vinyl or single carbon−carbon bond connection to different aromatic groups, 17,25,37,38 replacing the carbonyl group on the lactone moiety of the coumarin dyes with 4-pyridylacetonitrile and cyano(4-nitrophenyl)methylene moieties, 39−42 and by forming fused rhodamine dyes.…”

“…25−29 As a result, coumarins are utilized as a desirable and ideal fluorophore platform for a wide range of applications, such as biological imaging, sensing, and diagnostics for cations, 30 anions, 27,29,31 pH, 32−34 NADH, 17 H 2 S, 27,29,31 cysteine, homocysteine, and glutathione (GSH), 27,29,31 cellular membranes, and reactive oxygen and nitrogen species. 27,29,31,35,36 The fluorescence of coumarin fluorophores has been tuned to longer emission regions by extending the π-conjugation at the 3-or 4-position through a vinyl or single carbon−carbon bond connection to different aromatic groups, 17,25,37,38 replacing the carbonyl group on the lactone moiety of the coumarin dyes with 4-pyridylacetonitrile and cyano(4-nitrophenyl)methylene moieties, 39−42 and by forming fused rhodamine dyes. 34,43−46 A deep-red coumarin-based fluorescent probe has recently been developed for NADH-sensing applications by introducing a quinolinium moiety at the 3-position of coumarin through a vinyl bond and replacing the lactone carbonyl group with a dicyano group.…”

Synthesis of A Sulfonamide-Substituted Benzothiadiazole-Based Fluorescent Dye and Study of Its Application for Long-Term Cancer Cell Tracking

“…Traditional fluorescent derivatives such as 4-bora-3a,4adiaza-S-indacenes (BODIPYs), coumarins, rhodamines, and cyanines have widely used for bioimaging. [19][20][21][22][23][24][25][26][27] However, these mentioned structures are hard to synthesize and purify, easy photoquenching and photobleaching. [28][29] As a result, the construction and manufacture of stable fluorescent core structure is beneficial for promoting long-term tracking ability.…”