Metal Nanoshells

Metal nanoshells are ultrasmall particles whose light-absorbing properties can be specially tailored to specific applications in the visible and infrared regions of the spectrum. The particles can be made to selectively absorb or scatter light at virtually any wavelength, even at wavelengths where no natural light-absorbing materials exist. A metal nanoshell is a composite, layered nanoparticle whose color is determined by precisely controlling the thicknesses of the particle's constituent layers. This can be done so accurately that one can "design" metal nanoshells to have the color required for any application of choice. Metal Nanoshells were first developed in the Halas Nanoengineering Group at Rice.

Growth stages of gold shells around silica nanoparticles

Metal Nanoshell Research at Rice is truly interdisciplinary, involving research groups in four departments across both sciences and engineering. Single nanoshell devices have recently been fabricated in collaboration with Alex Rimberg in the Physics Department. These devices will be used to investigate fundamental phenomena in the area of low-temperature mesoscopic transport. Theoretical studies of electronic phenomena in nanoshell geometries are being conducted by Peter Nordlander, also in the Physics Department. In the Halas Nanoengineering Group, studies vary from fabrication of new and novel extensions of nanoparticle fabrication methods, integration of Metal Nanoshell properties with planar photonics device technology, and optical studies of Metal Nanoshells, including their ultrafast optical response, optical manipulation of nanoshell-based devices, and synthesis of unusual nanoshell-based composite materials. In terms of applications, Metal Nanoshells really deliver in the area of Biotechnology. In collaboration with Jennifer West in the Rice Bioengineering Department, Metal Nanoshells are being used as optically addressable biosensors, as active media in photo-thermally triggered drug delivery devices, and as the basis of a new bioassay technology which can sample whole blood, a property which is capable of revolutionizing current bioassay technology.