@article {1125,
	title = {Noble Metal Nanoparticle Pairs: Effect of Medium for Enhanced Nanosensing},
	journal = {Nano Letters},
	volume = {8},
	number = {12},
	year = {2008},
	note = {Jain, Prashant K. El-Sayed, Mostafa A.},
	month = {Dec},
	pages = {4347-4352},
	abstract = {In this Letter, we show using both a quasi-static model and discrete dipole approximation simulations of nanoparticle pairs that the surface plasmon resonance shift resulting from the electromagnetic coupling between noble metal nanoparticles increases with an increase in the dielectric constant of the medium. As the particle pair partners approach each other, there is an increase in the rate at which the plasmon resonance shifts in response to a medium refractive index change. Thus, the surface plasmon resonance of a plasmonic nanoparticle pair exhibits higher sensitivity to the environment/medium refractive index as compared to an isolated nanoparticle. The medium sensitivity of the particle pair is shown to increase near exponentially with a decrease in the interparticle separation between the nanoparticles. We therefore propose that enhanced plasmon resonance nanosensing may be achieved by employing coupled particles instead of colloids or arrays of noninteracting particles.},
	isbn = {1530-6984},
	doi = {10.1021/nl8021835},
	author = {Jain, Prashant K and El-Sayed, Mostafa A}
}
@article {1124,
	title = {Noble Metals on the Nanoscale: Optical and Photothermal Properties and Some Applications in Imaging, Sensing, Biology, and Medicine},
	journal = {Accounts of Chemical Research},
	volume = {41},
	number = {12},
	year = {2008},
	note = {Jain, Prashant K. Huang, Xiaohua El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Dec},
	pages = {1578-1586},
	abstract = {Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical and photothermal properties of noble metal nanoparticles arises from resonant oscillation of their free electrons in the presence of light, also known as localized surface plasmon resonance (LSPR). The plasmon resonance can either radiate light (Mie scattering), a process that finds great utility in optical and imaging fields, or be rapidly converted to heat (absorption); the latter mechanism of dissipation has opened up applications in several new areas. The ability to integrate metal nanoparticles into biological Systems has had greatest impact in biology and biomedicine. In this Account we discuss the plasmonic properties of gold and silver nanostructures and present examples of how they are being utilized for biodiagnostics, biophysical studies, and medical therapy. For instance, taking advantage of the strong LSPR scattering of gold nanoparticles conjugated with specific targeting molecules allows the mollecule-specific imaging and diagnosis of diseases such as cancer. We emphasize in particular how the unique tunability of the plasmon resonance properties of metal nanopartides through variation of their size, shape, composition, and medium allows chemists to design nanostructures geared for specific bio-applications. We discuss some interesting nanostructure geometries, including nanorods, nanoshells, and nanopartide pairs, that exhibit dramatically enhanced and tunable plasmon resonances, making them highly suitable for bio-applications. Tuning the nanostructure shape (e.g., nanoprisms, nanorods, or nanoshells) is another means of enhancing the sensitivity of the LSPR to the nanopartide environment and, thereby, designing effective biosensing agents. Metal nanopartide pairs or assemblies display distance-dependent plasmon resonances as a result of field coupling. A universal scaling model, relating the plasmon resonance frequency to the interpartide distance in terms of the particle size, becomes potentially useful for measuring nanoscale distances (and their changes) in biological systems. The strong plasmon absorption and photothermal conversion of gold nanoparticles has been exploited in cancer therapy through the selective localized photothermal heating of cancer cells. For nanorods or nanoshells, the LSPR can be tuned to the near-infrared region, making it possible to perform in vivo imaging and therapy. The examples of the applicators of noble metal nanostructures provided herein can be readily generalized to other areas of biology and medicine because plasmonic nanomaterials exhibit great range, versatility, and systematic tunability of their optical attributes.},
	isbn = {0001-4842},
	doi = {10.1021/ar7002804},
	author = {Jain, Prashant K and Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A}
}
