Comparison of visible and near-infrared wavelength-excitable fluorescent dyes for molecular imaging of cancer
Journal of Biomedical Optics
Targeted fluorescent molecular imaging probes may provide an optimal means of detecting disease. Stable, organic fluorophores can be repeatedly excited in vivo by propagated light and consequentially can provide large signal-to-noise ratios ͑SNRs͒ for image detection of target tissues. In the literature, many small animal imaging studies are performed with a red excitable dye, Cy5.5, conjugated to the targeting component. We report the comparison of the in vivo fluorescent imaging performance
... aging performance of a near-IR ͑NIR͒ and a red-excitable dye. Epidermal growth factor ͑EGF͒ was conjugated with Cy5.5 ͓excitation/emission ͑ex/em͒, 660/ 710 nm͔ or IRDye® 800CW ͑ex/em: 785/ 830 nm͒ for imaging EGF receptor ͑EGFr͒ positive ͑MDA-MB-468͒ and/or negative ͑MDA-MB-435͒ human breast cancer cell lines in subcutaneous xenograft models. The conjugates were injected intravenously at 1-nmol-dye equivalent with and without anti-EGFr monoclonal antibody C225, preadministered 24 h prior as a competitive ligand to EGFr. Our images show that while both agents target EGFr, the EGF-IRDye® 800CW evidenced a significantly reduced background and enhanced the tumor-to-background ratio ͑TBR͒ compared to the EGF-Cy5.5. Immunohistochemistry shows that EGF causes activation of the EGFr signaling pathway, suggesting that prior to use as a targeting, diagnostic agent, potential deleterious effects should be considered. © 2007 Society of Photo-Optical Instrumentation Engineers.