Controlled Assembly of Vesicle Layers on Layer-by-layer Particles via DNA Hybridization

We report here on the formation of layers of large unilamellar vesicles (LUVs) superimposed on Layer-by-Layer- (LbL-) particles. DNA oligonucleotides were covalently attached to the outermost negatively charged polyelectrolyte layer of the particles and thus vesicles, with complementary lipophilic DNAs incorporated into the membranes, could be assembled in layers via sequence specific hybridization (see figure). Entrapment of calcein, NBD-rhodamine FRET fusion assay, FRAP, and cryo electron microscopy proved that LUVs attached to LbL-particles remained intact. The assembly was reversible, e.g. heating above the melting temperature of the DNA-hybrids led to the dissociation of the vesicle layer. Fusion of vesicles attached to the LbL-particles and leakage of the entrapped molecules was triggered on demand by addition of melittin. Using different DNA sequences, lipid anchors or compositions of the membrane can regulate the assembly of layers. The LUVs-LbL-particles have many advantages: a controlled and reversible assembly, small and defined size, easy manipulation, biocompatibility, and biodegradability of the particles, and the possibility of a triggered release of different reactants entrapped in different layers of vesicles. LUVs-LbL-particles can be potentially used in diagnostics or for the organization and regulation of reactions on nanoscale.View Large Image | View Hi-Res Image | Download PowerPoint Slide