Fig. 1.

Chemical structure of ${}^{68}\mathrm{Ga}$-labeled 800CW-tilmanocept and its normalized absorbance (open) and fluorescence (solid) spectra. (a) The receptor-binding multimodal imaging probe is composed of NC units of amino-terminated leashes, ND units of diethylenetriaminepentaacetic acid (DTPA) groups, which chelate the nuclear imaging reporter ${}^{68}\mathrm{Ga}$, NDye units of the optical imaging reporter IRDye 800CW, and NM units of mannose, the receptor substrate. (b) Attachment of IRDye 800CW to tilmanocept produces a 6 nm red shift and an increase in the nonradiative peak (800CW-tilmanocept: triangle; IRDye 800CW: circle).