A diagnostic assay is developed using surface enhanced Raman spectroscopy (SERS) to detect biomolecules with gold nanoparticles. The gold nanoparticles are coated with goat anti-mouse IgG antibodies using the crosslinker Dithiobis(sulfosuccinimidyl propionate) (DTSSP) as a binding agent and the Raman dye nitrobenzenethiol (NBT). Free nanoparticles do not express a detectable Raman signal. In the presence of antigen, the nanoparticles come together to form aggregates, causing a strong signal from gold enhanced NBT. Initial studies used dynamic light scattering (DLS) to observe the antigen concentration range which effectively induces nanoparticle aggregation. While effective, formation of aggregates is only observable for a single antigen using DLS; therefore SERS will be used to study aggregation kinetics and will be used as a means to develop a multiplex assay. In an effort to optimize the assay and achieve a better limit of detection, gold-plated filters will be explored as a method of capturing and concentrating the nanoparticle aggregates for SERS detection.

Homogeneous SERS based immunoassay using gold nanoparticles

248th National Meeting (2014)

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