Highly Sensitive Surface-enhanced Raman Spectroscopy Nanoplatforms Based On Gold Nanoparticles Aggregates
Rowland, Kendrith Martin III
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The purpose of this project was to create a highly reproducible, cheap, and non-‐toxic aqueous gold nanoparticle platform designed for high intensity Surface Enhanced Raman Spectroscopy (SERS). To do this high purity tunable aqueous gold nanorods was created using a seed mediated method.1 The aqueous gold nanorods of aspect ratio 4 (46 ± 0.2 x 11 ± 0.4 nm) was aggregated using a mixture solvent (1:1 ethanol to water) solution for hot spots of high electromagnetic enhancement from the junctions between gold nanoparticles. The aggregation of these particles was tested high intensity SERS using trans-‐1,2-‐Bis(4-‐pyridyl)ethylene (BPE) reporter molecules.2 Aggregated gold nanorods of aspect ratio 4 showed enhancement factors up to 7.4 x 107 and showed higher enhancement in low concentration aggregated gold nanorods. Smaller aspect ratio aggregated gold nanospheres (47 ± 0.3 nm) showed higher enhancement factors of up to 1.04 x 109 . Thus, it was determined that gold nanospheres had an optimal concentration for high SERS. To control the aggregate size a surfactant capping method was used on the small aspect ratio gold nanorods and then coated with a mesoporous silica layer for an antibiofouling layer. Further studies will be preformed to improve aggregation conformation and high reproducibility of high SERS gold nanoparticle platforms. These platforms will then be further functionalized on its surface to detect specific analytes such as lactate, glucose, and other complex molecules of interest for potential in vivo use.