title: A label-free immunoassay based upon localized surface plasmon resonance of gold nanorods.
abstract: Robust gold nanorod substrates were fabricated for refractive index sensing based on localized surface plasmon resonance (LSPR). The substrate sensitivity was 170 nm/RIU with a figure of merit of 1.3. To monitor biomolecular interactions, the nanorod surfaces were covered with a self-assembled monolayer and conjugated to antibodies by carbodiimide cross-linking. Interactions with a specific secondary antibody were monitored through shifts in the LSPR spectral extinction peak. The resulting binding rates and equilibrium constant were in good agreement with literature values for an antibody-antigen system. The nanorod LSPR sensors were also shown to be sensitive and specific. These results demonstrate that given a sufficiently stable nanoparticle substrate with a well defined chemical interface, LSPR sensing yields similar results to the surface plasmon resonance technique, yet with much simpler instrumentation.
authors.affiliation: Department of Physics & Astronomy, Rice University, Houston, Texas 77005, USA.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Mayer
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Lee
authors.forename: Hongwei
authors.initials: H
authors.lastname: Liao
authors.forename: Betty C
authors.initials: BC
authors.lastname: Rostro
authors.forename: Amaris
authors.initials: A
authors.lastname: Fuentes
authors.forename: Peter T
authors.initials: PT
authors.lastname: Scully
authors.forename: Colleen L
authors.initials: CL
authors.lastname: Nehl
authors.forename: Jason H
authors.initials: JH
authors.lastname: Hafner
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003460:Crystallization / Q000379:methods; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013194:Staining and Labeling; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; C009495:titanium dioxide; D006046:Gold; D014025:Titanium