Directly detecting low concentrations of small molecules in aqueous environmental samples is often limited by similar molecular structures and function of the targeted species as well as complex sample matrices. When plasmonic nanoparticles synthesized using bottom-up strategies are used to facilitate detection, an additional limitation of signal irreproducibility from changing surface functionality further complicates both qualitative and quantitative detection. Herein, the plasmonic properties of gold nanostars are exploited for understanding how local surface chemistry impact surface-enhanced Raman scattering (SERS) signals using solution-phase gold nanostars for uranyl detection. The engineered roughness of the Au nanostar architectures and carboxylated alkanethiols promote uranyl cation adsorption. The localized surface plasmon resonance (LSPR) spectral properties are used to quantify alkanethiol layer thickness, which successfully promote uranyl coordination to the Au nanostars in neutral aqueous solutions. Quantitative uranyl detection is demonstrated for various functionalized Au nanostar samples as indicated by enhanced signals and red-shifts in the symmetric U(VI)-O stretch. These results indicate that SERS signals using functionalized Au nanostar substrates can provide quantitative detection of small molecules including the important environmental contaminant uranyl. As such, the development of this novel sensing platform could result in empowering technology to improve the health and safety for those living in regions where uranium contamination of ground water is a concern.

SERS sensors for direct detection of environmental contaminants

253rd National Meeting (2017)

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