Single plasmonic nanoparticle tracking studies of solid supported bilayers with ganglioside lipids

Laura B. Sagle, Laura K. Ruvuna, Julia M. Bingham, Chunming Liu, Paul S. Cremer, Richard P. Van Duyne

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Single-particle tracking experiments were carried out with gold nanoparticle-labeled solid supported lipid bilayers (SLBs) containing increasing concentrations of ganglioside (GM1). The negatively charged nanoparticles electrostatically associate with a small percentage of positively charged lipids (ethyl phosphatidylcholine) in the bilayers. The samples containing no GM1 show random diffusion in 92% of the particles examined with a diffusion constant of 4.3(±4.5) × 10-9 cm2/s. In contrast, samples containing 14% GM1 showed a mixture of particles displaying both random and confined diffusion, with the majority of particles, 62%, showing confined diffusion. Control experiments support the notion that the nanoparticles are not associating with the GM 1 moieties but instead most likely confined to regions in between the GM1 clusters. Analysis of the root-mean-squared displacement plots for all of the data reveals decreasing trends in the confined diffusion constant and diameter of the confining region versus increasing GM1 concentration. In addition, a linearly decreasing trend is observed for the percentage of randomly diffusing particles versus GM1 concentration, which offers a simple, direct way to measure the percolation threshold for this system, which has not previously been measured. The percolation threshold is found to be 22% GM1 and the confining diameter at the percolation threshold only ∼50 nm.

Original languageEnglish (US)
Pages (from-to)15832-15839
Number of pages8
JournalJournal of the American Chemical Society
Volume134
Issue number38
DOIs
StatePublished - Sep 26 2012

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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