Asymmetric bilayers by hemifusion: method and leaflet behaviors (Biophysical Journal)

We describe a new method to prepare asymmetric giant unilamellar vesicles (aGUVs) via hemifusion. Hemifusion of GUVs and a supported lipid bilayer (SLB), triggered by calcium, promotes the lipid exchange of the fused outer leaflets mediated by lipid diffusion. We used different fluorescent dyes to monitor the inner and the outer leaflets of the unsupported aGUVs. We confirmed that almost all new exchanged lipids in the aGUVs are found in the outer leaflet of these asymmetric vesicles. In addition, we test the stability of the aGUVs formed by hemifusion in preserving their contents during the procedure.