Efficient Fusion of Liposomes by Nucleobase Quadruple-Anchored DNA

5 years ago

Efficient Fusion of Liposomes by Nucleobase Quadruple-Anchored DNA

Qing Liu, Bart J. Crielaard, Alberto Rodríguez-Pulido, Jian Yang, Zhuojun Meng, Andreas Herrmann, Agnieszka Gruszka, Jan Willem de Vries, Alexander Kros

Anchoring DNA via hydrophobic units into the membrane of vesicles allows tagging of these nanocontainers with sequence information. Moreover, the hybridization of DNA on the surface of liposomes enables sequence specific functionalization, vesicle aggregation, and vesicle fusion. Specifically, DNA-hybridization-based approaches for fusion employing oligonucleotides terminally modified with one or two anchoring units were hindered by a limited degree of full fusion or by significant leakage during fusion. The current work deals with a new strategy for anchoring oligonucleotides on a membrane by lipid-modified nucleobases rather than by attaching hydrophobic units to the 3′- or 5′-termini. The lipid anchors were incorporated into the DNA sequence via phosphoramidite nucleotide building blocks during automated solid-phase synthesis allowing variation of the number and position of hydrophobic units along the DNA backbone. Single-stranded DNA functionalized with four lipid-modified nucleobases was stably grafted onto the membrane of lipid vesicles. It was found that the orientation of DNA hybridization and the number of anchoring units play a crucial role in liposomal fusion, which in the most efficient system reached remarkable 29 % content mixing without notable leakage. A powerful new approach is reported to achieve vesicle–vesicle fusion by employing DNA with four lipid-modified bases at the terminus to tightly anchor the nucleotide to the bilayer of vesicles. This strategy achieved a highly stable incorporation of DNA into the liposomal bilayer, thereby limiting dissociation and keeping the base-pairing nucleotides close to the surface and allowing for a markedly more efficient full fusion as compared to other, previously reported, anchoring strategies.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701379