Plasmonic vertical dimer arrays as elements for biosensing.
Localized surface plasmon resonances of metallic nanoparticles can be used for biosensing because of their sensitive dependence on the refractive index of the surrounding medium. The binding of molecules to the particles causes a change of the effective refractive index in their close vicinity, which leads to a reversible shift of the resonance. We present simulations and sensing experiments of a plasmon resonance based biosensor that makes use of the narrow antisymmetric resonance in coupled plasmonic vertical dimers. The sensitivity of the antisymmetric resonance is compared with that of a surface lattice resonance for refractive index sensing of bulk and of thin layers of molecules. The functionality of such a sensor surface is demonstrated via a testosterone immunoassay for detection of antibody from a solution by binding to surface-immobilized antigen in a fluidic channel.
Institute for Applied Physics and Center LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany. andreas.horrer@uni-tuebingen.de.
Andreas
A
Horrer
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Katrin
K
Krieg
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Kathrin
K
Freudenberger
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Sabrina
S
Rau
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Lothar
L
Leidner
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Günter
G
Gauglitz
Institute for Applied Physics and Center LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany.
Dieter P
DP
Kern
Institute for Applied Physics and Center LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany. monika.fleischer@uni-tuebingen.de.
Monika
M
Fleischer
D019281:Dimerization; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D056656:Lab-On-A-Chip Devices; D053768:Metal Nanoparticles / Q000737:chemistry*; D012031:Refractometry; D012822:Silicon Dioxide / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013739:Testosterone / Q000032:analysis*
D013739:Testosterone; D006046:Gold; D012822:Silicon Dioxide
Biosensing; Label-free immunoassay; Plasmonic nanostructures; Testosterone; Vertical dimer