Development of a rapid, cost effective, and accurate biosensor for proteins is important for many applications in clinical diagnostics. A Surface Enhance Raman Spectroscopy-linked aptasensor sandwich assay (SERS-LASA) was developed using two unique Raman-labeled aptamers as sensors for the model protein, thrombin. Its sensing mechanism is based on the formation of unique nanoparticle-on-film structure upon protein-mediated binding, leading to the formation of hotspots. We utilize a two distinct Raman labels for the nanoparticle and the film such that both labels can be enhanced together within the protein junction hotspot. The dual tag system allows for further ratiometric deconvolution of the spectra to determine signal contributions from both the film and nanoparticle. Unlike current assays that rely on enzymatic conversion of substrates that could potentially come from nonspecific binding or improper washing, our system is an amplification-free assay that produces signals solely derived from hotspot formation, thereby increasing the accuracy of the assay. The current generation of assay has an LOD in the subnanomolar range in 1% human serum, with the total assay time of 2 hours. The assay is expected to be a suitable platform for detecting biomolecules with any available pair affinity reagents.

Development of a SERS-based biomolecular assay

251st National Meeting (2016)

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