Figure 2.

(a) Degradation profiles of thioketal linkages in PATK after exposure to H₂O₂ at various concentrations for different periods of time, as determined by ¹H NMR spectroscopy. (b) Transmission electron micrographs of the DNA/PATK polyplexes (N/P = 100) before and after incubation with H₂O₂ for 12 h at 37 °C. Scale bars indicate 100 nm. (c) Generation of intracellular ROS in PC3 cells confirmed by fluorescence microscopy. Strong green fluorescence throughout the cells demonstrates the high levels of intracellular ROS in PC3 cells. (d) Confocal micrographs illustrating the intracellular localization of DNA/PATK and DNA/non-degradable poly(amine) polyplexes in PC3 cells. Cellular nuclei were counter-stained with DRAQ5 (blue). Yellow dots represent co-localized polymer (green) and DNA (red). Scale bars indicate 10 μm.