A new hybrid nanoparticle, i.e., a nanorice particle, which combines the
intense local fields of nanorods with the highly tunable plasmon
resonances of nanoshells, is described herein. This geometry possesses
far greater structural tunability than previous nanoparticle geometries,
along with much larger local field enhancements and far greater
sensitivity as a surface plasmon resonance (SPR) nanosensor than
presently known dielectric-conductive material nanostructures. In an
embodiment, a nanoparticle comprises a prolate spheroid-shaped core
having a first aspect ratio. The nanoparticle also comprises at least one
conductive shell surrounding said prolate spheroid-shaped core. The
nanoparticle has a surface plasmon resonance sensitivity of at least 600
nm RIU.sup.-1. Methods of making the disclosed nanorice particles are
also described herein.