Direct observation of lipid bilayer disruption by poly(amidoamine) dendrimers.
Chem Phys Lipids
; 132(1): 3-14, 2004 Nov.
Article
in En
| MEDLINE
| ID: mdl-15530443
ABSTRACT
Atomic force microscopy (AFM) is employed to observe the effect of poly(amidoamine) (PAMAM) dendrimers on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers. Aqueous solutions of generation 7 PAMAM dendrimers cause the formation of holes 15-40 nm in diameter in previously intact bilayers. This effect is observed for two different branch end-groups--amine and carboxyl. In contrast, carboxyl-terminated core-shell tectodendrimer clusters do not create holes in the lipid membrane but instead show a strong affinity to adsorb to the edges of existing bilayer defects. A possible mechanism for the formation of holes in the lipid bilayer is proposed. The dendrimers remove lipid molecules from the substrate and form aggregates consisting of a dendrimer surrounded by lipid molecules. Dynamic light scattering (DLS) measurements as well as 31P NMR data support this explanation. The fact that tectodendrimers behave differently suggests that their cluster-like architecture plays an important role in their interaction with the lipid bilayer.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Polyamines
/
Dimyristoylphosphatidylcholine
/
Lipid Bilayers
/
Liposomes
/
Membrane Fluidity
Language:
En
Journal:
Chem Phys Lipids
Year:
2004
Document type:
Article
Affiliation country:
United States