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Structural changes in lipid mesophases due to intercalation of dendritic polymer nanoparticles: Swollen lamellae, suppressed curvature, and augmented structural disorder

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)198-209
Number of pages12
JournalActa Biomaterialia
Volume104
Early online date3 Jan 2020
DOIs
DateAccepted/In press - 30 Dec 2019
DateE-pub ahead of print (current) - 3 Jan 2020

Abstract

Understanding interactions between nanoparticles and model membranes is relevant to functional nano-composites and the fundamentals of nanotoxicity. In this study, the effect of polyamidoamine (PAMAM) dendrimers as model nanoparticles (NP) on the mesophase behaviour of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) has been investigated using high-pressure small-angle X-ray scattering (HP-SAXS). The pressure-temperature () diagrams for POPE mesophases in excess water were obtained in the absence and presence of G2 and G4 polyamidoamine (PAMAM) dendrimers (29 Å and 45 Å in diameter, respectively) at varying NP-lipid number ratio (ν = 0.0002-0.02) over the pressure range p = 1-3000 bar and temperature range T = 20–80°C. The phase diagram of POPE exhibited the Lβ, Lα and HII phases. Complete analysis of the phase diagrams, including the relative area pervaded by different phases, phase transition temperatures (Tt) and pressures (pt), the lattice parameters (d-spacing), the pressure-dependence of d-spacing (Δd/Δp), and the structural ordering in the mesophase as gauged by the Scherrer coherence length (L) permitted insights into the size- and concentration-dependent interactions between the dendrimers and the model membrane system. The addition of dendrimers changed the phase transition pressure and temperature and resulted in the emergence of highly swollen lamellar phases, dubbed Lβ-den and Lα-den. G4 PAMAM dendrimers at the highest concentration ν = 0.02 suppressed the formation of the HII phase within the temperature range studied, whereas the addition of G2 PAMAM dendrimers at the same concentration promoted an extended mixed lamellar region in which Lα and Lβ phases coexisted.

    Research areas

  • Lipid Mesophases, PAMAM dendrimers, Nanoparticles, High-Pressure Small Angle X-ray Scattering, Nanotoxicity, Membrane Models, Cellular Uptake, Endocytosis, Synchrotron Scattering

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  • Authors accepted manuscript

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at https://www.sciencedirect.com/science/article/pii/S1742706119308797?via%3Dihub. Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 4.29 MB, PDF document

    Embargo ends: 3/01/21

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    Licence: CC BY-NC-ND

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