Fig. 4.

Two-photon confocal fluorescence imaging of GP-BAN (25 μM) stained with HepG2 cells. (a-d) Cells were incubated with GP-BAN (25 μM) at 37 °C for 30 min (f–h) Cells were pretreated with vildagliptin (50 μM) and then added GP-BAN (25 μM) at 37 °C for 30 min. Images were acquired under excitation at 805 nm with two fluorescent emission windows: (b, f) blue =420–460 nm; (c, g) green =495–540 nm. Scale bars =10 µm.