Chemical sensing and imaging with metallic nanorods.
In this Feature Article, we examine recent advances in chemical analyte detection and optical imaging applications using gold and silver nanoparticles, with a primary focus on our own work. Noble metal nanoparticles have exciting physical and chemical properties that are entirely different from the bulk. For chemical sensing and imaging, the optical properties of metallic nanoparticles provide a wide range of opportunities, all of which ultimately arise from the collective oscillations of conduction band electrons ("plasmons") in response to external electromagnetic radiation. Nanorods have multiple plasmon bands compared to nanospheres. We identify four optical sensing and imaging modalities for metallic nanoparticles: (1) aggregation-dependent shifts in plasmon frequency; (2) local refractive index-dependent shifts in plasmon frequency; (3) inelastic (surface-enhanced Raman) light scattering; and (4) elastic (Rayleigh) light scattering. The surface chemistry of the nanoparticles must be tunable to create chemical specificity, and is a key requirement for successful sensing and imaging platforms.
Murphy
Catherine J
CJ
Department of Chemistry & Biochemistry and the W. M. Keck Laboratory for Bionanoparticle Technology Discovery and Development, University of South Carolina, Columbia, SC 29208, USA. Murphy@mail.chem.sc.edu
Gole
Anand M
AM
Hunyadi
Simona E
SE
Stone
John W
JW
Sisco
Patrick N
PN
Alkilany
Alaaldin
A
Kinard
Brian E
BE
Hankins
Patrick
P
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006046:Gold / Q000737:chemistry*; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods; D020349:Surface Plasmon Resonance / Q000379:methods; D013499:Surface Properties
D012834:Silver; D006046:Gold