Figure 1. IRDye 800CW EGF imaged 96 h post injection. Orange ovals pinpoint region of orthotopic implanted prostate tumor. Images were captured with the Pearl® Imager with the pseudo-color representing the 800 nm channel.
Figure 2. Nude mouse bearing subcutaneous tumors, U87 (left hip) and A431(right hip), was imaged 24 hours post intravenous injection of IRDye 800CW RGD (1 nmole). Image was captured on the Pearl Imager; 800nm signal is presented in pseudo-color overlaid on a white light image of the mouse.
Cell surface receptors can be targeted for in vivo imaging by injection of agents that bind specifically to the receptor.
- Tumor cells often over-express certain cell surface receptors (for example, EGFR or integrins).
- Fluorescently-labeled molecules (such as ligands, antibodies, or drugs) that specifically bind these receptors can be used to visualize tumors inside the living animal.
- Epidermal growth factor receptor (EGFR), overexpressed on the cell surface of many cancer cells types1, can be targeted with a fluorescently labeled IRDye EGF agent for longitudinal studies of tumor progression2.
- Tumors over-expressing integrin receptors can be targeted with IRDye 800CW RGD Optical Probe3,4.
Near-infrared dyes, such as IRDye fluorophores, and carefully optimized hardware are critical for high-performance optical imaging.
- Near-infrared fluorophores exploit the spectral region where light absorption and scatter properties of tissue are most advantageous5. This enhances penetration depth (access of excitation light to the fluorophore) and escape of emitted fluorescence from the animal to reach the detector.
- Laser illumination delivers very intense excitation light of the correct wavelength, generating the brightest possible signal from the fluorescent agent.
- Intrinsic autofluorescence from animal tissue can mask the signal from optical probes. In the NIR spectral region, autofluorescence is dramatically lowered6,7.
Note: IRDye® 680LT dye products should not be used for small animal in vivo imaging or
In-Cell Western™ Assays. The higher level of fluorescent intensity creates high background making it unfavorable for use in these applications. We recommend using IRDye 680RD dye products for these applications.
- 1. Hong, W. and A. Ullrich. Oncology Biotherapeutics. 1(1): 5 (2000)
- 2. Kovar, J et al. Am J Pathol. 169(4):1415-26 (2006)
- 3. Kovar, J et al. Poster presentation, AACR Annual Meeting (2009)
- 4. Chen, K et al. Mol Imaging. 8(2): 65-73 (2009)
- 5. Hawrysz, DJ and Sevick-Muraca, EM. Neoplasia. 2(5):388-417 (2000)
- 6. Frangioni, JV. Curr Opin Chem Biol. 7(5): 626-34 (2003)
- 7. Adams, KE, et al. J Biomed Opt. 12(2): 024017 (2007)