Theoretical proposal for a biosensing approach based on a linear array of immobilized gold nanoparticles

S. M.Hashemi Rafsanjani, T. Cheng, S. Mittler, C. Rangan

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We propose a sensing mechanism for detection of analytes that can specifically recognized. The sensor is based on closely-spaced chains of functionalized gold nanoparticles (NPs) immobilized on a waveguide surface, with the signal detected by evanescent waveguide absorption spectroscopy. The localized surface plasmon spectrum of a linear array of closely-spaced, hemispherical gold NPs is calculated using the discrete dipole approximation. The plasmon band is found to broaden to a nanowirelike spectrum when a dielectric coating is put on the particles, and the light polarization is along the NP chain. The origin of this broadening is shown to be the polarization-dependent overlap of the evanescent fields of adjacent NPs upon application of the dielectric coating. These features suggests a mechanism for biosensing with an improved sensitivity compared with traditional NP biosensor methods.

Original languageEnglish (US)
Article number094303
JournalJournal of Applied Physics
Issue number9
StatePublished - May 1 2010
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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