Abstract
The thermal stabilities of supercoiled (SC) and linear/open circular (LIN/OC) forms of plasmid DNA when complexed with cationic lipids or cationic polymers used for cellular transfection were assessed using differential scanning calorimetry. Differences in the stability of SC DNA produced by the cationic lipids DOTAP (1,2‐dioleoyltrimethyl ammoniumpropane chloride), DSTAP (1,2‐distearyltrimethyl ammoniumpropane chloride), and DDAB (dimethyldioctadecylammonium bromide) upon complexation suggest possible effects of headgroup structure on the stability of SC DNA and minimal effects of lipid acyl chain saturation/unsaturation. Complexation of DNA with the cationic polymers polyethylenimine (PEI) or poly‐L‐lysine (PLL) (but not poly‐L‐arginine) resulted in a decreased stability of SC DNA when the DNA was in charge excess, although all polymers stabilized SC DNA when the polymer was in charge excess. The effects of these cationic polymers on the stability of SC DNA can be explained by changes produced in the tertiary structure of SC DNA upon binding and may reflect the importance of the topological constraint of supercoiling upon the stability of the resulting complexes.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
