Figure 1. IRDye 800CW EGF Optical Probe was used to detect an A431 tumor (800 nm channel, pseudo-color). IRDye 680 BoneTag™ was used to visualize skeletal structures (700 nm channel, grayscale), aiding in anatomical localization of the tumor. Image captured with the Pearl® Imager.
Structural imaging is often employed to more precisely localize an area of disease.
- Bone mineralization may be marked with a fluorescently-labeled bone agent.
- A second targeting agent, labeled with a spectrally distinct fluorescent dye, can then be used to localize and track disease — a tumor, for example — in the same animal.
- When the two images are overlaid, the bone structure is displayed in one color, and the other target appears in a different color.
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 advantageous1. 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 lowered2,3.
Figure 2. IRDye 800CW BoneTag was used to demonstrate resolution of structural imaging. Image captured with the Pearl Imager.
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. Hawrysz, DJ and Sevick-Muraca, EM. Neoplasia 2(5): 388-417 (2000)
- 2. Frangioni, JV. Curr Opin Chem Biol. 7: 626-34 (2003)
- 3. Adams, KE, et al. J Biomed Opt. 12: 024017 (2007)