Design and Synthesis of Metallic Nanostars for Surface Enhanced Raman Scattering

Surface enhanced Raman scattering (SERS) is a technique which is ultrasensitive and can be used to provide discriminatory signals from molecules of interest such as DNA, proteins, explosives and drugs of abuse. The majority of enhancing materials used for SERS are based on plasmonic materials and most notably spherical particles of gold or silver. In this project we will make use of a new class of nanoparticles which we are investigating, nanostars. The nanostars can be made quite easily through a reduction process to generate particles that are highly enhancing in terms of their Raman scattering. We will build on preliminary work where we have shown how to synthesise these nanoparticles and how their properties can be tailored in terms of their ability to scatter or absorb light. We intend to expand our research capabilities in using nanostars for SERS by combining them with appropriate Raman reporters such as some of the chalcogen dyes that have recently been published on from the group as well as some traditional small molecule reporters. To make these nanostar Raman reporter conjugates stable, the project will investigate a range of different coatings such as silica, PEG and most unusually DNA. We will also investigate the opportunity to develop responsive particles which change Raman signal on encountering different environments and provide Raman signals at different wavelengths under different conditions. The objectives are:
1. To synthesise and characterise a range of different metallic nanostars with Raman reporter molecules over a range of different excitation wavelengths.
2. To investigate a range of different coatings to stabilise these nanostar Raman reporter conjugates and in collaboration with the external funder tune the properties of these nanomaterials to suit the end use.
3. To produce nanomaterials which provide different responses depending on the environmental conditions such as changes in temperature, pH or solvent.