@article {810,
	title = {Dark-field light scattering imaging of living cancer cell component from birth through division using bioconjugated gold nanoprobes},
	journal = {Journal of Biomedical Optics},
	volume = {15},
	year = {2010},
	pages = {046025},
	abstract = {Novel methods and technologies that could extend and complement the capabilities of the prevailing fluorescence microscope in following the cell cycle under different perturbations are highly desirable in the area of biological and biomedical imaging. We report a newly designed instrument for long-term light scattering live cell imaging based on integrating a homebuilt environmental cell incubation minichamber and an angled dark-field illumination system into a conventional inverted light microscope. Peptide-conjugated gold nanoparticles that are selectively delivered to either the cytoplasmic or nuclear region of the cell are used as light scattering contrast agents. The new system enables us to carry out continuous and intermittence-free dark-field live cell imaging over several tens of hours. A variety of applications of this imaging system are demonstrated, such as monitoring the nuclear uptake of peptide-conjugated gold nanoparticles, tracking the full cycle of cancer cells from birth to division, following the chromosome dynamics during cell mitosis, and observing the intracellular distribution of gold nanoparticles after cell division. We also discuss the overall effect of nuclear targeting gold nanoparticles on the cell viability of parent and daughter cells.},
	doi = {10.1117/1.3477179},
	url = {http://dx.doi.org/10.1117/1.3477179},
	author = {Qian, Wei and Huang, Xiaohua and Kang, Bin and El-Sayed, Mostafa A}
}
@article {1104,
	title = {Delivery of molecules into cells using carbon nanoparticles activated by femtosecond laser pulses},
	journal = {Nature Nanotechnology},
	volume = {5},
	number = {8},
	year = {2010},
	note = {Chakravarty, Prerona Qian, Wei El-Sayed, Mostafa A. Prausnitz, Mark R.},
	month = {Aug},
	pages = {607-611},
	abstract = {A major barrier to drug and gene delivery is crossing the cell{\textquoteright}s plasma membrane. Physical forces applied to cells via electroporation(1), ultrasound(2) and laser irradiation(3-6) generate nanoscale holes in the plasma membrane for direct delivery of drugs into the cytoplasm. Inspired by previous work showing that laser excitation of carbon nanoparticles can drive the carbon-steam reaction to generate highly controlled shock waves(7-10), we show that carbon black nanoparticles activated by femtosecond laser pulses can facilitate the delivery of small molecules, proteins and DNA into two types of cells. Our initial results suggest that interaction between the laser energy and carbon black nanoparticles may generate photo-acoustic forces by chemical reaction to create transient holes in the membrane for intracellular delivery.},
	isbn = {1748-3387},
	doi = {10.1038/nnano.2010.126},
	author = {Chakravarty, P. and Qian, Wei and El-Sayed, Mostafa A and Prausnitz, M. R.}
}
@article {1114,
	title = {The Dependence of the Plasmon Field Induced Nonradiative Electronic Relaxation Mechanisms on the Gold Shell Thickness in Vertically Aligned CdTe-Au Core-Shell Nanorods},
	journal = {Nano Letters},
	volume = {9},
	number = {11},
	year = {2009},
	note = {Neretina, Svetlana Dreaden, Erik C. Qian, Wei El-Sayed, Mostafa A. Hughes, Robert A. Preston, John S. Mascher, Peter},
	month = {Nov},
	pages = {3772-3779},
	abstract = {The dependence of the plasmon field enhancement of the nonradiative relaxation rate of the band gap electrons in vertically aligned CdTe-Au core-shell nanorods on the plasmonic gold nanoshell thickness is examined. Increasing the thickness of the gold nanoshell from 15 to 26 nm is found to change the decay curve from being nonexponential and anisotropic to one that is fully exponential and isotropic (i.e., independent of the nanorod orientation with respect to the exciting light polarization direction). Analysis of the kinetics of the possible electronic relaxation enhancement mechanisms is carried out, and DDA simulated properties of the induced plasmonic field of the thin and thick gold nanoshells are determined. On the basis of the conclusions of these treatments and the experimental results, it is concluded that by increasing the nanoshell thickness the relaxation processes evolve from multiple enhancement mechanisms, dominated by highly anisotropic Auger processes, to mechanism(s) involving first-order excited electron ejection process(es). The former is shown to give rise to nonexponential anisotropic decays in the dipolar plasmon field of the thin nanoshell, while the latter exhibits an exponential isotropic decay in the unpolarized plasmonic field of the thick nanoshell.},
	isbn = {1530-6984},
	doi = {10.1021/nl901960w},
	author = {Neretina, Svetlana and Dreaden, Erik and Qian, Wei and El-Sayed, Mostafa A and Hughes, Robert A and Preston, John S and Mascher, Peter}
}
@article {1134,
	title = {Dependence of the threshold energy of femtosecond laser ejection of gold nanoprisms from quartz substrates on the nanoparticle environment},
	journal = {Journal of Physical Chemistry C},
	volume = {111},
	number = {25},
	year = {2007},
	note = {Tabor, Christopher Qian, Wei El-Sayed, Mostafa A.},
	month = {Jun},
	pages = {8934-8941},
	abstract = {Recently, it was reported that gold nanoprisms in a monolayer array on a quartz substrate were ejected in air when irradiated with femtosecond laser pulses near their surface plasmon absorption maximum. It was deduced from the measured reduction in particle thickness upon irradiation that the ejection mechanism involved ablation of surface atoms from the gold particle, which generates an intense pressure at the particle-substrate interface. The present study reports on this phenomenon when the substrate-bound nanoparticle is immersed in a liquid environment. In this system, it is found that the nanoparticle ejection requires less than one tenth the energy required if the system was irradiated in air. The ejected nanoparticle is also found to increase in thickness instead of the decrease observed in air. These results suggest another photoinitiated ejection mechanism, different from surface ablation, when the particles are surrounded by a liquid environment. From this and other spectroscopic and microscopic results on the ejected nanoprisms, we suggest a mechanism that involves energy transfer from the photoexcited nanoprism to the solvent within cavities and defects at the particle-substrate interface. The hot-solvent molecules result in an intense pressure at the particle-substrate interface, resulting in particle ejection. Ejection is proposed to consist of two processes, namely nanoparticle-substrate dissociation and nanoparticle solvation and diffusion away from the substrate. These two processes have independently been studied as a function of solvent property.},
	isbn = {1932-7447},
	doi = {10.1021/jp070282q},
	author = {Tabor, C. E. and Qian, Wei and El-Sayed, Mostafa A}
}
