Figure 5.
Measured photophysical and experimentally-determined physical properties of the non-NIR fluorescent rosol dyes and THQ- Rosol. A) Fluorescence emission profile of THQ-Rosol accentuating i) the effect of its lower calculated molecular orbital energy gap value and ii) the difference in its maximum fluorescence emission wavelength when compared to those of the non-NIR fluorescent rosol dyes. B) Photostability of the generic molecular fluorescent dyes commonly used for lymphatic mapping applications, non-NIR fluorescent rosol dyes, and THQ-Rosol. C) Experimentally-determined off-on fluorescence intensity pH-profile of a non-NIR fluorescent rosol dye, THQ- Rosol, and its proposed analogue having a pendant benzene moiety with a charged 2-carboxylate group (-COO-), all of which accentuate that by minimizing the N-C3’ torsion angle of a 3’-amino-6’-hydroxyxanthene-based scaffold as an integrated component of a molecular platform having a pendant benzene moiety without a charged 2-carboxylate group a pKa value can be modulated such that it could afford a pH- insensitive and maximal fluorescence response. The green-shaded region identifies tumor-draining lymphatics pH levels (pH 6.8–7.4).