| This research centers around techniques to engineer the properties of noble-metal nanostructures for applications in surface-enhanced Raman spectroscopy (SERS) and biomedicine. Many of these potential applications are made possible by the strong localized surface plasmon resonance (LSPR) of noble-metal nanostructures, which is heavily influenced by the particle's morphology.;The first part of this work focuses on the solution-phase synthesis of Ag nanostructures. In this section, I demonstrate the synthesis of Ag nanostructures with two different morphologies that are interesting for fundamental SERS studies: anisotropically truncated octahedrons and large, single-crystalline spheres. In both syntheses, control over etching was critical to morphological control.;The second part of this work discusses galvanic replacement reactions, which can be used to create a variety of hollow, porous nanostructures whose LSPR can be tuned into the near infrared region, a spectral range particularly interesting for biomedical applications due to reduced light attenuation in soft tissue. In this section, I will describe how the nanostructures resulting from galvanic replacement reactions can be engineered by controlling the morphology of the Ag nanostructures used as templates or the metal salt(s) titrated during the reaction. Specifically, I will discuss how the use of template particles with non-uniform surfaces influences the final morphology and how the progression of a galvanic replacement reaction using two different precursors (e.g. HAuCl 4 and Na2PdCl4) depends strongly on the order that they are added.;In the final part of this work, I will discuss the biocompatibility of Au-Ag nanocages with different compositions and surface coatings and their use in two biomedical imaging techniques: as contrast agents in photoacoustic mapping of sentinel lymph nodes and as novel three-photon luminescence probes for in vitro imaging. |
