Fluorescence Bioassays with Plasmonic Amplification for Biomarker Analysis

Jakub Dostalek Biosensor Technologies, AIT - Austrian Institute of Technology, Vienna, Austria Martin Bauch Biosensor Technologies, AIT - Austrian Institute of Technology, Vienna, Austria Simone Hageneder Biosensor Technologies, AIT - Austrian Institute of Technology, Vienna, Austria Agnes Rainer Biosensor Technologies, AIT - Austrian Institute of Technology, Vienna, Austria Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore, Singapore Khulan Sergelen Biosensor Technologies, AIT - Austrian Institute of Technology, Vienna, Austria Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore, Singapore

This paper will discuss implementations of plasmon-enhanced fluorescence (PEF) assays for detection of biomarkers. Such assays utilize fluorophore labels and their near-field coupling with surface plasmon field allows increasing the signal-to-noise ratio of detected fluorescence signal by the combination of increased excitation rate, improved quantum yield of emitter, and directional fluorescence emission. This amplification strategy enables detection of lower amounts of captured analyte from investigated samples, which translates to improved limit of detection [1].

Fig. a) PEF and its implementation with b) tightly-confined cLSP modes and c) deeply probing SPPs.

Fig. a) PEF and its implementation with b) tightly-confined cLSP modes and c) deeply probing SPPs

Relation of the assay sensitivity with surface plasmon field confinement, the surface area that can be used for analyte capture, and the size of analyte species will be discussed. Examples of detection of small biomolecules with size of several nanometers [2], exosomes with the size of around hundred nanometers, and bacterial pathogens exhibiting the size of around micrometer [3] will be presented. Plasmonic nanostructures providing the enhancement factor of around 10² [4] and possible routes for even stronger enhancement >10³ [5] will be investigated for the analysis of species at femtomolar concentrations. New PEF applications for detection of trace amounts of biomarkers in bodily fluids such as saliva and blood serum will be given.

References:

[1] M. Bauch, et al., Plasmonics (2014), 9 (4), 781-799.

[2] Y. Wang, et al, Analytical Chemistry (2009) 81, 9625.

[3] C. J. Huang, et al., Analytical Chemistry (2011) 83, 674–677.

[4] M. Bauch, et al., Optics Express (2014), 22(26) 32026-32038.

[5] M. Bauch et al, Optics Express (2013), 21(17), 20470.

jakub.dostalek@ait.ac.at