title: Volume and porosity thermal regulation in lipid mesophases by coupling mobile ligands to soft membranes.
abstract: Short DNA linkers are increasingly being exploited for driving-specific self-assembly of Brownian objects. DNA-functionalized colloids can assemble into ordered or amorphous materials with tailored morphology. Recently, the same approach has been applied to compliant units, including emulsion droplets and lipid vesicles. The liquid structure of these substrates introduces new degrees of freedom: the tethers can diffuse and rearrange, radically changing the physics of the interactions. Unlike droplets, vesicles are extremely deformable and DNA-mediated adhesion causes significant shape adjustments. We investigate experimentally the thermal response of pairs and networks of DNA-tethered liposomes and observe two intriguing and possibly useful collective properties: negative thermal expansion and tuneable porosity of the liposome networks. A model providing a thorough understanding of this unexpected phenomenon is developed, explaining the emergent properties out of the interplay between the temperature-dependent deformability of the vesicles and the DNA-mediated adhesive forces.
authors.affiliation: Biological and Soft Systems Sector, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Lucia
authors.initials: L
authors.lastname: Parolini
authors.affiliation: Interdisciplinary Center for Nonlinear Phenomena and Complex Systems &Service de Physique des Systémes Complexes et Mécanique Statistique, Université libre de Bruxelles, Campus Plaine, CP 231, Boulevard du Triomphe, Brussels B-1050, Belgium.
authors.forename: Bortolo M
authors.initials: BM
authors.lastname: Mognetti
authors.affiliation: Biological and Soft Systems Sector, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Jurij
authors.initials: J
authors.lastname: Kotar
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Erika
authors.initials: E
authors.lastname: Eiser
authors.affiliation: Biological and Soft Systems Sector, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
authors.affiliation: Biological and Soft Systems Sector, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Di Michele
mesh_terms: D001483:Base Sequence; D003102:Colloids / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D007091:Image Processing, Computer-Assisted; D008024:Ligands; D008081:Liposomes / Q000378:metabolism*; D008566:Membranes / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D008962:Models, Theoretical; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry*; D016062:Porosity; D013696:Temperature
chemical_list: D003102:Colloids; D008024:Ligands; D008081:Liposomes; D004247:DNA