Chemical Structure CA Index Name Glycine, N,N 0 -[(3 0 ,6 0 -dihydroxy-3-oxospiro[isobenzofuran-1(3H),9 0 -[9H]xanthene]-2 0 ,7 0 -diyl) bis(methylene)]bis[N-(carboxymethyl)-Other Names Bis [N, N-bis(carboxymethyl)aminomethyl] fluorescein; Fluorescein, 2 0 ,7 0 -bis[[bis(carboxymethyl) amino]methyl]-; Fluorescein-bis(methyliminodiacetic acid); Spiro[isobenzofuran-1(3H),9 0 -[9H]xanthene], glycine derivative; 2,7-Bis[N,N-bis(carboxymethyl)aminomethylene]fluorescein; Acetic acid, [(3 0 ,6 0 -dihydroxy-2 0 ,7 0 -fluorandiyl)bis(methylenenitrilo)]tetra-; Calcein; Fluorescein complexon; Fluorexon; NSC 298193; Oftasceine Merck Index Number Not listed Chemical/Dye Class Xanthene Molecular Formula C 30 H 26 N 2 O 13 Molecular Weight 622.53 Physical Form Yellow-orange to brown powder Solubility Soluble in water, ethanol, N,N-dimethyl formamide, dimethyl sulfoxide Melting Point 200 C Boiling Point (Calcd.) 952.7 AE 65.0 C, pressure: 760 Torr pH Range 6.0-7.2Color Change at pH Weak green fluorescence (6.0) to strong green fluorescence (7.2) pK a 6.67 Absorption (l max ) 494 nm Emission (l max ) 517 nm Synthesis Synthetic methods 1-7 Staining Applications Calcium ions; 8,9 fluoride ions; 10 iron ions; 11-13 mercury ions; 14 peptides; 2 proteins; 2 antibodies; 2 atherosclerotic plaque; 1,15 bone; 16,17 cells; 18-20 fish; 21 liposomes; 22,23 neurons; 8 skin; 24 tumor cells; 1,25 inflammations; 1 lymphokines; 1 hepatocytes 3,4 Biological Applications Calcium indicator; 8,9 fluoride indicator; 10 iron indicator; 11-13 mercury indicator; 14 detecting nucleic acids, 1,26 proteins; 27 treating osteoporosis; 28 drug delivery systems 1,29 Industrial Applications Chemical mechanical polishing; 1,30 coatings; 31 photoresists 32 Safety/Toxicity Acute toxicity; 33 cytotoxicity; 1,34 mutagenicity; 35 neurotoxicity; 36 ophthalmotoxicity 37 2. Hahn, K. M.; Toutchkine, A.; Muthyala, R.; Kraynov, V.; Bark, S. J.; Burton, D. R.; Chamberlain, C. Labeled peptides, proteins and antibodies and processes and intermediates useful for their preparation. O OH HO N N COOH COOH HOOC HOOC O O 71 3. Horiuchi, K.; Saji, H.; Arano, Y.; Yokoyama, A. Ligandin binding phthalein complexone complex of technetium for hepatic function studies. Eur. J. Nucl. Med. 1990, 16, 137-142. 4. Saji, H.; Yokoyama, A.; Arano, Y.; Tanaka, H.; Odori, T.; Morita, R.; Torizuka, K. Phthalein and fluorescein derivatives with an effective technetium-99m labeled state for a hepatobiliary transport: 99mTc-PC, a new hepatobi-liary radiopharmaceutical. Pribil, R. New metallochromic indicators of the complexon type. Chem. Ind. 1957, 233-234. 8. Dravid, S. M.; Murray, T. F. Fluorescent detection of Ca 2 þ -permeable AMPA/kainate receptor activation in murine neocortical neurons. Neurosci. Lett. 2003, 351, 145-148. 9. Sugita, M.; Hirono, C.; Tanaka, S.; Nakahari, T.; Imai, Y.; Kanno, Y.; Shiba, Y. Visualization of the secretory process involved in Ca 2 þ -activated fluid secretion from rat submandibular glands using the fluorescent dye, calcein. Eur. J. Cell Biol. 2000, 79, 182-191. 10. Li...