Label-free Surface Plasmon Polariton Application for Labelled Biomolecule Detection

Abstract

In this study, we present an experimental application of label-free surface plasmon polaritons (SPP) for the detection of CF®680 dye labelled bovine serum albumin (BSA). We show the optical properties of the BSA-CF680 complex and the adsorption analysis of this bio-complex on the SPP sensing surface. The total internal reflection ellipsometry and fluorescence microscopy method were used to analyse absorption and fluorescence properties of BSA-CF680. It was demonstrated that the SPP’s quality factor increased when a labelled BSA-CF60 biomolecule complex was used compared to non-labelled BSA, indicating coupling between SPP and biomolecules. However, the number of biomolecules adsorbed to the surface show a higher emitter count or lower mode volume is required to reach the strong coupling regime. This approach of combining a label-free method with labelled biomolecules can pave the way for an alternative biomolecule detection method through spectral analysis.