CURRENT RESEARH

Plasmonic Nanostructures: Synthesis, Properties, Applications

Gold and silver nanostructures support plasmon resonances, which are the oscillations of their free electrons when excited by light. Plasmon resonances lead to interesting optical properties such as resonant abosorption for nanoscale heating, bright resonant scattering, focussing of light near the nanoparticle surface, and propagation of light as plasmons down elongated structures. We work on the synthesis, properties, and biological applications of plasmonic nanostructures.

Our latest plasmonic structure is the gold nanobelt - an elongated gold nanowire with rectangular cross section. They have nanometers-scale cross sections, similar to gold nanorods, but lengths up to several hundred microns. Their plasmon resonances are tunable with cross sectional aspect ratio, which can be seen in the dark field scattering image below.

Recent Studies: The nanobelts can have non-uniform cross sections leading to novel plasmonic structures (below left), and they support plasmon propagation (below right).

We are also studying how surface enhanced Raman scattering (SERS) from plasmonic structures may be used for structural biology. Our recent publicatin on Analytical SERS revealed a structrural transition in the surfactant (CTAB) bilayer that surrounds gold nanorods (below). We are currently working to surround nanoparticles with lipid membranes to detect their structure and interactions with peptides.