DNA Hybridization-Mediated Liposome Fusion at the Aqueous Liquid Crystal Interface

The prominence of receptor-mediated bilayer fusion in cellular biology motivates development of biomimetic strategies for studying fusogenic mechanisms. An approach is reported here for monitoring receptor-mediated fusion that exploits the unique physical and optical properties of liquid crystals (LC). PEG-functionalized lipids are used to create an interfacial environment capable of inhibiting spontaneous liposome fusion with an aqueous/LC interface. Then, DNA hybridization between oligonucleotides within bulk phase liposomes and a PEG-lipid monolayer at an aqueous/LC interface is exploited to induce receptor-mediated liposome fusion. These hybridization events induce strain within the liposome bilayer, promote lipid mixing with the LC interface, and consequently create an interfacial environment favoring re-orientation of the LC to a homeotropic (perpendicular) state. Furthermore, the bi-functionality of aptamers is exploited to modulate DNA hybridization-mediated liposome fusion by regulating the availability of the appropriate ligand (i.e., thrombin). Here, a LC-based approach for monitoring receptor (i.e., DNA hybridization)-mediated liposome fusion is demonstrated, liposome properties that dictate fusion dynamics are explored, and an example of how this approach may be used in a biosensing scheme is provided.