Figure 2.

Real-time in-cell ¹⁹F NMR spectra of ¹⁹F-R8 and ¹⁹F-T6 at 4 °C. (a) An expansion of the typical ¹⁹F NMR spectra of 80 μM ¹⁹F-R8 (Figure 1a) in PBS (0 min), and 4, 6, 8, 10, 12, 14 and 16 min after the addition to HL60 cells at 4 °C. The peak top of ¹⁹F-R8 in the absence of cells (0 min) is designated by blue dotted line. The red arrow indicates a new component observed at the first step after addition to cells. (b) The difference spectra obtained by subtracting the spectrum of ¹⁹F-R8 in PBS (0 min) from the respective spectra of Figure 2a in the presence of HL60 cells. Note that the top spectrum (Free) in Figure 2b is the ¹⁹F NMR spectrum of ¹⁹F-R8 in PBS (0 min). Four components of ¹⁹F-R8 in cell outside (Free), bound to glycosaminoglycan (GAG), bound to cell membrane (Membrane), and in cytosol (Cytosol, *) are designated by the dotted lines in blue, black, green, and red, respectively. For comparison, the real-time in-cell ¹⁹F NMR (c) and the difference spectra (d) of 100 μM ¹⁹F-T6 in PBS (0 min), and at 4, 8, and 16 min after the addition to HL60 cells are also shown. The upper spectrum in (d) represents ¹⁹F-T6 in PBS (0 min).