Novel fluorophores as building blocks for optical probes for in vivo near infrared fluorescence (NIRF) imaging.
Aiming at the identification of new fluorescent reporters for targeted optical probes, we assessed the application-relevant features of a novel asymmetric cyanine, DY-681, in comparison to the only clinically approved dye indocyanine green (ICG), the golden imaging standard Cy5.5, and the asymmetric cyanine DY-676 successfully exploited by us for the design of different contrast agents. This comparison included the analysis of the spectroscopic properties of the free fluorophores and their thermal stability in aqueous solution as well as their cytotoxic potential. In addition, the absorption and emission features of IgG-conjugated DY-681 were examined. The trimethine DY-681 exhibited spectral features closely resembling that of the pentamethine Cy5.5. Its high thermal stability in phosphate buffer saline (PBS) solution in conjunction with its low cytotoxicity, reaching similar values as determined for Cy5.5 and DY-676, renders this dye more attractive as ICG and, due to its improved fluorescence quantum yield in PBS, also superior to DY-676. Although in PBS, Cy5.5 was still more fluorescent, the fluorescence quantum yields (Phi(f)) of DY-681 and Cy5.5 in PBS containing 5 mass-% bovine serum albumin (BSA) were comparable. Labeling experiments with DY-681 and the model antibody IgG revealed promisingly high Phi(f) values of the bioconjugated dye.
Pauli
Jutta
J
BAM Federal Institute for Materials Research and Testing, Division I.5, Richard-Willstaetter-Str. 11, 12489 Berlin, Germany.
Brehm
Robert
R
Spieles
Monika
M
Kaiser
Werner A
WA
Hilger
Ingrid
I
Resch-Genger
Ute
U
D000818:Animals; D000906:Antibodies; D002232:Carbocyanines; D002417:Cattle; D004396:Coloring Agents / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry*; D003952:Diagnostic Imaging; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D007208:Indocyanine Green / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry
D000906:Antibodies; C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D004396:Coloring Agents; D003287:Contrast Media; D005456:Fluorescent Dyes; D012710:Serum Albumin, Bovine; D007208:Indocyanine Green