Fluorochrome-labeled monoclonal antibody with characteristic M-shaped spectral peak for optical imaging: Dual-labeling versus mixture of fluorochromes

In this work two different fluorochromes （Alexa 594 and Alexa 680） are conjugated to the same monoclonal antibody （Cetuximab） for obtaining a characteristic M-shaped dual-peak spectrum. Dual-labeling of Cetuximab by mixing both fluorochromes before the conjugation step gives spectral results similar to those of mixing of fluorochrome-labeled Cetuximab after the conjugation step （P 〉 0.05）. In conclusion, both methods may be used equivalently for producing a dual-labeled single-antibody probe. Future studies may test whether the M-shaped spectrum may increase the diagnostic confidence in tumor-targeted multispectral optical imaging.