Table 1

Fluorescent probe specifications
Fluorophore
 Soluble
 Ex
 Em
 Initial/Peak Assimilation Time (min)
 Exposure Concentration
7-benzyloxyresorufin
 DMSO
 560
 590
 30/45
 50 μM
In vivo CYP3A activity. Uptake via gill, in vivo metabolism in gill and gut, good for investigating blood to bile transport, IHBPs, EHBPs and intestinal lumen.
7-Ethoxyresorufin
 DMSO

30/45
 10–50 μM
In vivo imaging of CYP1A activity. Uptake via gill, in vivo metabolism in gill and liver. CYP 1A2, 2E Substrate
Acridine Orange
 H2O
 500
 526
1–5 μM
In vivo labeling of DNA, RNA. Good for apoptosis, interacts with DNA and RNA by intercalation or electrostatic attractions.
BODIPY 505/515: 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene
 DMSO
 502
 510
 15/20
 5 μM-100 nM
Uptake via gill, active transport through hepatobiliary system, concentrative blood to bile transport, and secretion from gall bladder into gut lumen. Good for elucidation of gill, IHBP, EHBP, intestinal lumen. Non-Polar, Lipophilic.
BODIPY FL C5-ceramide: N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)sphingosine
 DMSO
 358
 461
 20/45
 5 μM–100 nM
Putative passive transport in vivo. Uptake via gill, transport through cardiovascular and hepatobiliary systems and secretion from gall bladder into gut lumen.
Bodipy Verapamil
 DMSO
 504
 511
 20/60
In vivo Bodipy verapamil localized to hepatocytic cytosol in discrete vesicles. Transport to bile was not observed in the time frame assayed, which was 90 minutes.
BODIPY® 493/503: 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY® 493/503)
 DMSO
 493
 504
 15/20
 10 μM
Uptake via gill, active transport through hepatobiliary system, concentrative blood to bile transport, and secretion from gall bladder into gut lumen. Good for elucidation of gill, IHBPs, EHBPs, intestinal lumen. Lipophilic, amphiphilic.
BODIPY® 581/591 C5-HPC (Phosphocholine) PC: 2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexadecanoyl-sn-glycero-3-phosphocholine
 DMSO
 582
 593
 15/20
 30 nM
OIn vivo labeling of intrahepatic and extrahepatic biliary system. Uptake via gill. Hepatobiliary transport to gut lumen. Diffuse fluorescence in hepatocyte cytosol.
CellTrace™ Oregon Green® 488 carboxylic acid diacetate, succinimidyl ester (carboxy-DFFDA, SE) *cell permeant* *mixed isomers
 DMSO
 <300
 none
 15/20
 10–100 μM
In vivo labeling of hepatic nuclei, potential for detection of apoptosis
DAPI: 4',6-diamidino-2-phenylindole, dihydrochloride
 H2O, DMF
 358
 461
 15/60
 0.3 – 3.0 μM
In vivo nuclear labeling of virtually all cell types associated with gill, gut, liver, and cardiovascular system.
DAPI Diacetate: 4',6-diamidino-2-phenylindole, diacetate
 H2O, MeOH
 358
 461
 15/60
 0.3 – 3.0 μM
DAPI diacetate is water-soluble form. In vivo nuclear labeling.
Fluorescein-5-isothiocyanate (FITC 'Isomer I')
 DMSO
 494
 519
 10/30
 1 μM – 50 nM
Excellent in vivo probe for elucidating biliary system. In vivo labeling of intrahepatic and extrahepatic biliary system. Hepatobiliary transport to intestinal lumen. Uptake via gill.
MitoTracker® Green FM
 DMSO
 490
 516
 20/30
 25–200 nM
In vivo labeling of hepatocytes.
SYTO® 16 green fluorescent nucleic acid stain
 DMSO
 488
 518
 15/30
 10 nM-1 μM
In vivo nuclear labeling of epithelia and endothelia, putative in vivo probe for apoptosis.
SYTO® 27 green fluorescent nucleic acid stain
 DMSO
 495
 537
 15/50
 10 nM-1 μM
Apoptosis.
SYTOX® Orange nucleic acid stain
 DMSO
 547
 570
 15/50
 0.1–5 μM
Apoptosis
YO-PRO®-1 iodide (491/509)
 DMSO
509
 15/60
 1 μM
Apoptosis
YOYO-1 Iodide (491/509)
 DMSO
 491
 509
 15/50
 2 – 5 nM
In vivo accumulated in interstitial spaces, some labeling of vasculature. Typically used for assays for cell enumeration, cell proliferation and cell cycle.

Eighteen fluorescent probes were selected for in vivo application based on their molecular weight, utility in elucidating desired structure/function, biocompatibility, and in vivo transport properties. The fluorescent probe, a description of application(s), the molecular weight (M.W.), solvent used for stock preparation (solubility), fluorescence excitation and emission wavelengths (Ex/Em), initial and peak fluorescence times (Initial/Peak Fluorescence (min)), and effective aqueous exposure concentrations are given.

Hardman et al. Comparative Hepatology 2008 7:7   doi:10.1186/1476-5926-7-7