In recent years, Surface Enhanced Raman Spectroscopy (SERS) has become valuable because it allows for the cost effective, rapid detection of small molecules without destroying or altering them. Particularly, in biology and chemistry fields, it allows one to identify biological samples like DNA and proteins, detect trace levels of explosives, and can be used in medical diagnostics.
This summer Willa Mihalyi-Koch ’19 and Aida Shadrav ’17, under the instruction of Assistant Professor of Chemistry Farah Dawood, worked to enhance the signaling of Raman Spectroscopy by fabricating nanostructured metal surfaces as large-area SERS sensors for detecting low concentrations of molecules. Due to galvanic displacement process, the metallic silver dendrites (highly branched, crystalline nanostructures) were able to grow directly on a copper substrate. Here, silver ions are reduced while the copper metal gets oxidized in a red-ox reaction where only three ingredients are required: silver ions, copper metal, and water. This spontaneous electrochemical process results in silver dendritic nanostructures that enhance the Raman signal due to their large surface area.
So far the team has fabricated different morphologies of silver dendrites under conditions where the silver ion concentration, temperature, and counter-ion ratio have been varied. For example, at very low silver ion concentrations, they observed fractal patterns representing fine dendritic silver nanostructures, and at higher concentrations, they found multi-faceted, large crystals of silver metal.
This research has allowed the student researchers to gain experience using a variety of techniques, such as Scanning Electron Microscopy, X-ray Diffraction, and Raman Spectroscopy. Shadrav said that she wants to apply the techniques learned in Dawood’s lab for her senior thesis and future research. Mihalyi-Koch also noted that the research itself helped her get a sense of chemistry outside of the structure of a classroom. “Professor Dawood allowed us to directly contribute our own ideas to the work, which made us really have a sense of ownership over our project,” she added.
Mihalyi-Koch plans to concentrate in chemistry. She is especially interested in inorganic and physical chemistry. Shadrav hopes to attend dental school after graduating from Hamilton and hopes to still conduct research as a dental student. She believes this experience has enhanced her interest in research and venturing into the unknown.