Many kinds of nanoscale materials have size- and shape-tunable physical properties arising from their reduced dimensions and high surface-area-to-volume ratio. We synthesize magnetic and noble metal nanoparticles using a “bottom-up” approach starting from molecular precursors. Surface modification of nanoparticles with organic molecules and inorganic overcoatings imparts additional chemical, physical, and biological functionality. The surface plasmon resonance of gold nanoparticles depends on their shape and is sensitive to interparticle coupling. Magnetic nanoparticles have size-dependent magnetic properties and can be manipulated with magnetic fields, for example to direct assembly into chains. Incorporating magnetic and plasmonic nanoparticles into soft polymers makes possible remote actuation with magnetic fields and light.

Dr. Tracy’s research interests include the synthesis, characterization, and self-assembly of noble metal, magnetic, and multifunctional nanoparticles and their applications in soft robotics, sensors, and medicine.