Figure 3.

Reductive treatment approach. (a) Schematic illustration of the reductive treatment approach for the determination of the relative proportion of internalized receptor-ligand complexes. (b) Proposed structure of the non-fluorescent hydrocyanine after treatment of the fluorescent cyanine (Cy3B) with NaBH₄. (c) Spectroscopic validation of the reductive treatment of the Cy3B-conjugated fluorescent ligand 1a with NaBH₄. Emission spectra (λ_ex = 530 nm) of the Cy3B-conjugated ligand 1a in the presence and absence of NaBH₄ (30 mM) in dPBS. Hydro-1a shows negligible fluorescence emission.