Fig. 4.

Cellular uptake of PNA-neamine conjugates by Huh7 cells. MH14 cells grown in a monolayer were incubated at room temperature for 6 h with fluorescein-tagged 5 μm of naked PNA (A) or 2 μm of PNA-neamine (B) conjugate. The cells were then washed, detached, and resuspended at 2 × 10⁶ cells/ml in PBS containing 2% FCS. Uptake was monitored by FACScan. Although PNA is neutral and has no charge, it is not taken up by the cell, although its neamine conjugate is efficiently internalized. C, localization of PNA-neamine conjugate in MH14 cells. Cells were incubated with 2 μm of fluorescein-tagged PNA-neamine conjugate. After 6 and 12 h of incubation, cells were washed and stained first with wheat germ agglutinin conjugated with rhodamine to label the membrane glycoproteins (red) to visualize the membrane boundary and then with DAPI to stain the nuclear DNA (blue). Uptake of PNA-neamine shows green fluorescence measured at 488 nm. Images were obtained Nikon A1R confocal microscope.