Bottom-Up Fabrication of Hybrid Plasmonic Sensors: Gold-Capped Hydrogel Microspheres Embedded in Periodic Metal Hole Arrays.
The high potential of bottom-up fabrication strategies for realizing sophisticated optical sensors combining the high sensitivity of a surface plasmon resonance with the exceptional properties of stimuli-responsive hydrogel is demonstrated. The sensor is composed of a periodic hole array in a gold film whose holes are filled with gold-capped poly(N-isoproyl-acrylamide) (polyNIPAM) microspheres. The production of this sensor relies on a pure chemical approach enabling simple, time-efficient, and cost-efficient preparation of sensor platforms covering areas of cm2. The transmission spectrum of this plasmonic sensor shows a strong interaction between propagating surface plasmon polaritons at the metal film surface and localized surface plasmon resonance of the gold cap on top of the polyNIPAM microspheres. Computer simulations support this experimental observation. These interactions lead to distinct changes in the transmission spectrum, which allow for the simultaneous, sensitive optical detection of refractive index changes in the surrounding medium and the swelling state of the embedded polyNIPAM microsphere under the gold cap. The volume of the polyNIPAM microsphere located underneath the gold cap can be changed by certain stimuli such as temperature, pH, ionic strength, and distinct molecules bound to the hydrogel matrix facilitating the detection of analytes which do not change the refractive index of the surrounding medium significantly.
Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems , Heisenbergstr. 3, 70569 Stuttgart, Germany.
Markus
M
Weiler
Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller Universität Jena , Albert Einstein Straße 15, 07745 Jena, Germany.
Christoph
C
Menzel
Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller Universität Jena , Albert Einstein Straße 15, 07745 Jena, Germany.
Thomas
T
Pertsch
Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology , Wolfgang- Gaede-Str. 1, 76131 Karlsruhe, Germany.
Rasoul
R
Alaee
Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology , Wolfgang- Gaede-Str. 1, 76131 Karlsruhe, Germany.|Institute of Nanotechnology, Karlsruhe Institute of Technology , P.O. Box 3640, 76021 Karlsruhe, Germany.
Carsten
C
Rockstuhl
Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems , Heisenbergstr. 3, 70569 Stuttgart, Germany.|Institute of Chemistry, University of Potsdam , Am Mühlenberg 3, 14476 Potsdam OT Golm, Germany.
Claudia
C
Pacholski
bottom-up; hole array; hydrogel; sensor; surface plasmon resonance