title: Artificial Membrane Fusion Triggered by Strain-Promoted Alkyne-Azide Cycloaddition.
abstract: Artificial systems for controlled membrane fusion applicable for drug delivery would ideally use triggers that are orthogonal to biology. To apply the strain-promoted alkyne-azide cycloaddition (SPAAC) to drive membrane fusion, oxo-dibenzocyclooctyne (ODIBO)-lipid 1 was designed, synthesized, and studied alongside azadibenzocyclooctyne (ADIBO)-lipids 2-4 to assess fusion with liposomes containing azido-lipid 5. Lipids 1-2 were first shown to be effective for liposome derivatization. Next, fusion was evaluated using liposomes containing 1 and varying ratios of PC and PE via a FRET dilution fusion assay, and a 1:1 PC-to-PE ratio yielded the greatest signal change attributed to fusion. Finally, lipids 1-4 were compared, and 1 yielded the greatest triggering of fusion, while 2-4 yielded varying efficacies depending on the structural features of each lipid. Fusion was further validated through STEM studies showing larger multilamellar assemblies after liposome mixing, and FRET assay results supporting the mixing of liposome aqueous contents. This work provides a platform for triggered fusion toward drug delivery applications and an understanding of the effects of lipid structure and membrane composition on fusion.
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Whitehead
authors.affiliation: Department of Chemistry, The University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: McNitt
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Mattern-Schain
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Carr
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Shahrina
authors.initials: S
authors.lastname: Alam
authors.affiliation: Department of Chemistry, The University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Popik
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Michael D
authors.identifier: 0000-0001-8737-5910
authors.initials: MD
authors.lastname: Best
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001372:Aza Compounds / Q000737:chemistry; D001386:Azides / Q000737:chemistry*; D061565:Cycloaddition Reaction; D034242:Cyclooctanes / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D008561:Membrane Fusion
chemical_list: D000480:Alkynes; D001372:Aza Compounds; D001386:Azides; D034242:Cyclooctanes; D008055:Lipids; D008081:Liposomes