title: Melting transition in lipid vesicles functionalised by mobile DNA linkers.
abstract: We study phase behaviour of lipid-bilayer vesicles functionalised by ligand-receptor complexes made of synthetic DNA by introducing a modelling framework and a dedicated experimental platform. In particular, we perform Monte Carlo simulations that combine a coarse grained description of the lipid bilayer with state of art analytical models for multivalent ligand-receptor interactions. Using density of state calculations, we derive the partition function in pairs of vesicles and compute the number of ligand-receptor bonds as a function of temperature. Numerical results are compared to microscopy and fluorimetry experiments on large unilamellar vesicles decorated by DNA linkers carrying complementary overhangs. We find that vesicle aggregation is suppressed when the total number of linkers falls below a threshold value. Within the model proposed here, this is due to the higher configurational costs required to form inter-vesicle bridges as compared to intra-vesicle loops, which are in turn related to membrane deformability. Our findings and our numerical/experimental methodologies are applicable to the rational design of liposomes used as functional materials and drug delivery applications, as well as to study inter-membrane interactions in living systems, such as cell adhesion.
authors.affiliation: Université Libre de Bruxelles (ULB), Department of Physics, Interdisciplinary Center for Nonlinear Phenomena and Complex Systems & Service de Physique des Systèmes Complexes et Mécanique Statistique, Campus Plaine, CP 231, Blvd du Triomphe, B-1050 Brussels, Belgium. bmognett@ulb.ac.be.
authors.forename: Stephan Jan
authors.initials: SJ
authors.lastname: Bachmann
authors.affiliation: Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. ld389@cam.ac.uk.
authors.forename: Jurij
authors.initials: J
authors.lastname: Kotar
authors.affiliation: Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. ld389@cam.ac.uk.
authors.forename: Lucia
authors.initials: L
authors.lastname: Parolini
authors.affiliation: Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK and Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, WC1E 6BT, UK.
authors.forename: Anđela
authors.identifier: http://orcid.org/0000-0002-7854-2139
authors.initials: A
authors.lastname: Šarić
authors.affiliation: Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. ld389@cam.ac.uk.
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
authors.affiliation: Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. ld389@cam.ac.uk.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Di Michele
authors.affiliation: Université Libre de Bruxelles (ULB), Department of Physics, Interdisciplinary Center for Nonlinear Phenomena and Complex Systems & Service de Physique des Systèmes Complexes et Mécanique Statistique, Campus Plaine, CP 231, Blvd du Triomphe, B-1050 Brussels, Belgium. bmognett@ulb.ac.be.
authors.forename: Bortolo Matteo
authors.initials: BM
authors.lastname: Mognetti
mesh_terms: D004247:DNA / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D009010:Monte Carlo Method; D044366:Transition Temperature; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D053835:Unilamellar Liposomes; D004247:DNA