Fig. 11.

DNA retention by polyplexes at different N/P ratios stored at room temperature and 2–8°C for 7 days studied using agarose gel electrophoresis. PMPC-DB/pDNA polyplexes containing 20 μg/ml pDNA at N/P 4, 8, and 10 were prepared in 10 mM citrate buffer and further diluted 5x using 10 mM phosphate buffer pH 8.0, whereas PEI/pDNA polyplexes were prepared in 10 mM HEPES buffer pH 7.4. Naked pDNA was diluted in 10 mM citrate buffer followed by 5x dilution with 10 mM phosphate buffer. The samples were stored at room temperature and in a 2–8°C fridge. Polyplexes containing 0.4 μg pDNA were electrophoresed immediately after preparation or 1, 4, and 7 days post-preparation on a 0.8% w/v agarose gel containing 0.5 μg/mL ethidium bromide.