Structural evolution of supported lipid bilayers intercalated with quantum dots

Magdalena Wlodek, Anna Slastanova, Laura J Fox, Nick Taylor, Oier Bikondoa, Michal Szwarzynski, Marta Kolasińska-Sojka, Piotr Warszyński, Wuge H Briscoe

Research output: Contribution to journalArticle (Academic Journal)

Abstract

Hypothesis
Supported lipid bilayers (SLBs) embedded with hydrophobic quantum dots (QDs) undergo temporal structural rearrangement.

Experiments
Synchrotron X-ray reflectivity (XRR) was applied to monitor the temporal structural changes over a period of 24 h of mixed SLBs of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) / 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-ethanolamine (POPE) intercalated with 4.9 nm hydrophobic cadmium sulphide quantum dots (CdS QDs). The QD-embedded SLBs (QD-SLBs) were formed via rupture of the mixed liposomes on a positively charged polyethylene imine (PEI) monolayer. Atomic force microscopy (AFM) imaging provided complementary characterization of the bilayer morphology.

Findings
Our results show time-dependent perturbations in the SLB structure due to the interaction upon QD incorporation. Compared to the SLB without QDs, at 3 h incubation time, there was a measurable decrease in the bilayer thickness and a concurrent increase in the scattering length density (SLD) of the QD-SLB. The QD-SLB then became progressively thicker with increasing incubation time, which – along with the fitted SLD profile – was attributed to the structural rearrangement due to the QDs being expelled from the inner leaflet to the outer leaflet of the bilayer. Our results give unprecedented mechanistic insights into the structural evolution of QD-SLBs on a polymer cushion, important to their potential biomedical and biosensing applications.
Original languageEnglish
Pages (from-to)409-417
Number of pages9
JournalJournal of Colloid and Interface Science
Volume562
Early online date26 Nov 2019
DOIs
Publication statusPublished - 7 Mar 2020

Keywords

  • Bilayer structure
  • Membranes intercalated with quantum dots
  • Nanoparticle-membrane interactions
  • Supported lipid bilayers
  • X-ray reflectivity (XRR)

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