title: Single nanoparticle based optical pH probe.
abstract: This paper describes the development of a nanoscale optical pH probe based upon the surface-enhanced Raman scattering (SERS) properties of silica-gold core-shell nanoparticles. In this approach, a thin layer of gold is deposited onto a core of silica to form a metallic nanoshell with surface plasmon modes in the red-to-near-infrared spectral region. The surface of the nanoshell is functionalized with a pH-sensitive SERS reporter molecule, 4-mercaptopyridine (4-MPy). The SERS spectra of 4-MPy is shown to be sensitive to the pH of the surrounding media within the range of 3 to 7. In addition, it is shown that individual silica-gold core-shell nanoparticles yield more reliable SERS spectra than aggregates of core-shell nanoparticles.
authors: Department of Chemistry, Western Washington University, Bellingham, Washington 98225-9150, USA.
authors: Rebecca A
authors: RA
authors: Jensen
authors: Jennifer
authors: J
authors: Sherin
authors: Steven R
authors: SR
authors: Emory
mesh_terms: D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: D006046:Gold; D012822:Silicon Dioxide