title: DPPG Liposomes Adsorbed on Polymer Cushions: Effect of Roughness on Amount, Surface Composition and Topography.
abstract: The adsorption of intact liposomes onto solid supports is a fundamental issue when preparing systems with encapsulated biological molecules. In this work, the adsorption kinetic of 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) liposomes onto cushions prepared from commom polyelectrolytes by the layer-by-layer technique was investigated with the main objective of finding the surface conditions leading to the adsorption of intact liposomes. For this purpose, different cushion surface roughnesses were obtained by changing the number of cushion bilayers. The adsorbed amount per unit area was measured through quartz crystal microbalance, surface morphology was characterized by atomic force microscopy, and the surface composition was assessed by X-ray photoelectron spectroscopy. The results show that (1) the amount of adsorbed lipids depends on the number of cushion bilayers, (2) the cushions are uniformly covered by the adsorbed lipids, and (3) the surface morphology of polymer cushions tunes liposome rupture and its adsorption kinetics. The fraction of ruptured liposomes, calculated from the measured amount of adsorbed lipids, is a function of surface roughness together with other surface morphology parameters, namely the dominating in-plane spatial feature size, the fractal dimension, and other textural features as well as amplitude and hybrid parameters.
authors.affiliation: †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Andreia A
authors.initials: AA
authors.lastname: Duarte
authors.affiliation: ‡Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Botelho do Rego
authors.affiliation: §Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Salerno
authors.affiliation: †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Paulo A
authors.initials: PA
authors.lastname: Ribeiro
authors.affiliation: ∥Biotechnology Agroalimentary and Biomedical Analysis Group, Moulay Ismaïl University, Faculty of Sciences, Biology Department, B.P. 11201, Zitoune, Meknes, Morocco.
authors.forename: Nezha
authors.initials: N
authors.lastname: El Bari
authors.forename: Benachir
authors.initials: B
authors.lastname: Bouchikhi
authors.affiliation: †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Raposo
mesh_terms: D000327:Adsorption; D017709:Fractals; D017612:Gold Compounds / Q000737:chemistry; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D015394:Molecular Structure; D010715:Phosphatidylglycerols / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties
chemical_list: D017612:Gold Compounds; D008081:Liposomes; D010715:Phosphatidylglycerols; D011108:Polymers; C030345:1,2-dipalmitoylphosphatidylglycerol