Modulation of density and orientation of amphiphilic DNA anchored to phospholipid membranes. I. Supported lipid bilayers.
In the present series of papers, we describe the results of a systematic study on the anchoring of cholesterol-tagged oligonucleotides to phospholipids bilayers followed by membrane-assisted hybridization of the complementary strand in solution. This paper describes the anchoring of novel cholesterol-modified DNA-18mers in supported lipid bilayers (SLB) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine: we compared the behavior of two anchoring functionalities differing in the number of cholesterol units and in the length of a spacer group. Quartz Crystal Microbalance with impedance monitoring (QCM-Z) measurements showed that both oligonucleotides insert into the bilayer membrane through cholesterol anchoring; however, dramatic differences, in terms of surface organization and thickness, are found as the number of anchoring units increases. In the case of multiple cholesterol units, a peculiar three-regimes concentration dependence was revealed and correlated to the effective size of the adsorbing units. Interestingly, for high oligonucleotide concentration, the adsorption process was rationalized in terms of a compaction model of amphiphilic DNA molecules. QCM-Z temperature cycles of the SLB-anchored double strands provided clear evidence for reversible hybridization at the bilayer interface.
Gambinossi
Filippo
F
Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3-Sesto Fiorentino, 50019 Florence, Italy.
Banchelli
Martina
M
Durand
Adeline
A
Berti
Debora
D
Brown
Tom
T
Caminati
Gabriella
G
Baglioni
Piero
P
D002784:Cholesterol / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry*; D011791:Quartz
D008051:Lipid Bilayers; D009841:Oligonucleotides; D010713:Phosphatidylcholines; D011791:Quartz; D004247:DNA; D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine