title: Phospholipid membrane encapsulation of nanoparticles for surface-enhanced Raman scattering.
abstract: Lipid-encapsulated surface-enhanced Raman scattering (SERS) nanoparticles, with promising applications in biomedical diagnostics, were produced. Gold nanoparticles, 60 nm in diameter, were coated with a ternary mixture of DOPC, sphingomyelin, and cholesterol. The lipid layer is versatile for engineering the chemical and optical properties of the particles. The stability of the lipid-encapsulated particles is demonstrated over a period of weeks. The versatility of the layer is demonstrated by the incorporation of three different Raman-active species using three different strategies. The lipid layer was directly observed by TEM, and the SERS spectrum of the three dye species was confirmed by Raman spectroscopy. UV-vis absorption and dynamic light scattering provide additional evidence of lipid encapsulation. The encapsulation is achieved in aqueous solution, avoiding phase transfer and possible contamination from organic solvents. Furthermore, when fluorescent dye-labeled lipids were employed in the encapsulant, the fluorescence and SERS activity of the particles were controlled by the use of dissolved ions in the preparation solution.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Canada.
authors.forename: Shell
authors.initials: S
authors.lastname: Ip
authors.forename: Christina M
authors.initials: CM
authors.lastname: MacLaughlin
authors.forename: Nikhil
authors.initials: N
authors.lastname: Gunari
authors.forename: Gilbert C
authors.initials: GC
authors.lastname: Walker
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D012235:Rhodamines; D006046:Gold