Figure 3.

¹⁹F NMR pH response of (A) C₇E₂ and (B) C₇K₃. Both C₇E₂ and C₇K₃ line shapes were found to be robust to pH changes during titration. (C) C₇K₃ and C₇E₂ both showed an increase in NMR signal in response to pH starting around 5.5. C₇E₂ signal reached maximum at pH 6.5, whereas C₇K₃ signal increased slowly through the pH values tested. (D) Nile red fluorescence assay of C₇E₂ and C₇K₃. Concentration of F-PA is plotted versus blue shift of the Nile red florescence peak (measured at 658 nm). Dotted line is fluorescence maximum of Nile red in water. Both compounds exhibit detectable blue shifts (and therefore critical aggregation concentrations) at or below 0.1 mM. This implies that, at the 2 mM concentration and pH 7.5, less than 5% of compound is in the monomeric state.