The microstructure of DNA-egg yolk phosphatidylcholine-gemini surfactants complexes: effect of the spacer length.
BACKGROUND
The length of spacer of gemini surfactants affects the DNA packing in DNA-neutral phospholipid-gemini surfactant complexes.


METHODS
The microstructure of complexes DNA-egg yolk phosphatidylcholine (EYPC)-alkane-α,ω-diyl-bis(dodecyl\xaddimethylammonium bromides) (CnGS, spacer n=2-12, n is even) was studied using small angle X-ray diffraction.


RESULTS
At EYPC:CnGS=1:1 mol/mol, the condensed lamellar phase was identified in complexes with CnGS, n=2-4, whereas longer spacer (n≥6) induced a hexagonal phase. The condensed lamellar phase Lαc was observed in the range 2\≤ EYPC:GnGS≤10 (mol/mol) in all complexes. The distance between adjacent DNA strands increases linearly with decreasing surface charge density of EYPC-CnGS vesicles. We determined the increase in dDNA 0.40±0.03 nm/1 mol of EYPC from the slope of dDNA=f (molEYPC/molCnGS) in the range of molar ratios 2≤EYPC:CnGS≤5. At lower surface charge density, EYPC:CnGS>5 mol/mol, the length of CnGS spacer (n=6-10) modulates the DNA-DNA distance.


CONCLUSIONS
Both the short spacer of CnGS and the low molar ratio EYPC:CnGS result in the closest DNA-DNA packing. A high surface charge density of membrane was reported as a key parameter for transfection efficiency of Lαc phase-forming complexes.
Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University, Bratislava, Slovakia. uhrikova@fpharm.uniba.sk
Daniela
D
Uhríková
Petra
P
Pullmannová
Adriana
A
Sabíková
Ferdinand
F
Devínsky
Sergio S
SS
Funari
D004247:DNA / Q000737:chemistry*; D004530:Egg Yolk / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014961:X-Ray Diffraction
D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D004247:DNA