Interactions between PAMAM dendrimers and DOPC lipid multilayers: Membrane thinning and structural disorder

Laura J. Fox, Anna Slastanova, Nicolas Taylor, Magdalena Wlodek, Oier Bikondoa, Robert M. Richardson, Wuge H. Briscoe*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)

Abstract

Background: Understanding the structure of hybrid nanoparticle-lipid multilayers is of fundamental importance to their bioanalytical applications and nanotoxicity, where nanoparticle-membrane interactions play an important role. Poly(amidoamine) (PAMAM) dendrimers are branched polymeric nanoparticles with potential biomedical applications due to precise tunability of their physicochemical properties. Here, the effect of PAMAM dendrimers (2.9–4.5 nm) with either a hydrophilic amine (NH2) or a hydrophobic C12 chain surface termination on the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayers has been studied for the first time. Methods: DOPC multilayers were created by the liposome-rupture method via drop-casting dendrimer-liposome dispersions with the dendrimers added at different concentrations and at three different stages. The multilayer structure was evaluated via the analysis of the synchrotron X-ray reflectivity (XRR) curves, obtaining the bilayer d-spacing, the coherence length from the Scherrer (Ls) analysis of the Bragg peaks, and the paracrystalline disorder parameter (g). Results: Dendrimer addition led to lipid bilayer thinning and more disordered multilayer structures. Larger hydrophobic dendrimers caused greater structural disruption to the multilayers compared to the smaller dendrimers. The smallest, positively charged dendrimers at their highest concentration caused the most pronounced bilayer thinning. The dendrimer-liposome mixing method also affected the multilayer structure due to different dendrimer aggregation involved. Conclusions: These results show the complexity of the effect of dendrimer physicochemical properties and the addition method of dendrimers on the structure of mixed dendrimer-DOPC multilayers. General significance: These insights are useful for fundamental understanding of nanotoxicity and future biomedical application of nanocomposite multilayer materials in which nanoparticles are added for enhanced properties and functionality.

Original languageEnglish
Article number129542
JournalBiochimica et Biophysica Acta - General Subjects
Early online date24 Jan 2020
DOIs
Publication statusE-pub ahead of print - 24 Jan 2020

Keywords

  • Lipid multilayers
  • Model membranes
  • Nanoparticle-membrane hybrids
  • Nanoparticle-membrane interactions
  • Nanotoxicity
  • PAMAM dendrimers
  • X-ray reflectivity

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