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Interactions between Dendritic Polymer Nanoparticles and Lipid Mesophases: Swollen Lamellae, Suppressed Curvature, and Augmented Structural Disorder

27 Pages Posted: 15 Aug 2019 First Look: Under Review

See all articles by Laura J. Fox

Laura J. Fox

University of Bristol - School of Chemistry; Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

Lauren Matthews

University of Bristol - School of Chemistry; Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

Holly Stockdale

University of Bristol - School of Chemistry

Supakit Pichai

University of Bristol - School of Chemistry; Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

Tim Snow

Diamond Light Source, Harwell Science and Innovation Campus

Robert M. Richardson

School of Physics, HH Wills Physics Laboratory, University of Bristol

Wuge H. Briscoe

University of Bristol - School of Chemistry

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 (p-T) diagrams for POPE mesophases in excess water were obtained in the presence and absence of G2 and G4 polyamidoamine (PAMAM) dendrimers (29 Å and 45 Å in diameter, respectively) at NP-lipid number ratios 0.0002-0.02) over the pressure range p = 1-3000 bar and temperature range T = 20-80 °C. The p-T 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 number ratio (0.02) suppressed the formation of the HII phase within the temperature range studied, whereas the addition of G2 PAMAM dendrimers at number ratio = 0.02 promoted an extended mixed lamellar region in which Lα and Lβ phases coexisted.

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

Suggested Citation

Fox, Laura J. and Matthews, Lauren and Stockdale, Holly and Pichai, Supakit and Snow, Tim and Richardson, Robert M. and Briscoe, Wuge H., Interactions between Dendritic Polymer Nanoparticles and Lipid Mesophases: Swollen Lamellae, Suppressed Curvature, and Augmented Structural Disorder (August 13, 2019). Available at SSRN: https://ssrn.com/abstract=3436428

Laura J. Fox

University of Bristol - School of Chemistry

Cantock's Close
Bristol
United Kingdom

Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

United Kingdom

Lauren Matthews

University of Bristol - School of Chemistry

Cantock's Close
Bristol
United Kingdom

Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

United Kingdom

Holly Stockdale

University of Bristol - School of Chemistry

Cantock's Close
Bristol
United Kingdom

Supakit Pichai

University of Bristol - School of Chemistry

Cantock's Close
Bristol
United Kingdom

Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol

United Kingdom

Tim Snow

Diamond Light Source, Harwell Science and Innovation Campus

United Kingdom

Robert M. Richardson

School of Physics, HH Wills Physics Laboratory, University of Bristol

United Kingdom

Wuge H. Briscoe (Contact Author)

University of Bristol - School of Chemistry ( email )

Cantock's Close
Bristol
United Kingdom

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