We present the design, implementation and characterization of an integrated surface plasmon resonance
biosensor chip involving diffractive optical coupling elements avoiding the need of prism coupling. The
integrated sensor chip uses the angular interrogation principle and includes two diffraction gratings and the SPR
sensing zone. The theoretical design is presented as well as the fabrication procedure. Experimental results,
using reference index fluids, are compared to theoretical predictions and prism coupling experimental results.
We believe that this architecture is perfectly suitable for low cost and reproducible SPR biochemical sensor
chips since the sensing zone can be functionalized as any other one.
Surface plasmon resonance (SPR) biosensors have become a central tool for the study of biomolecular interactions,
chemical detection, and immunoassays in various fields. SPR biosensors offer unparalleled advantages such as label-free
and real-time analysis with very high sensitivity. To further push the limits of SPR capabilities, novel SPR structures and
approaches are being actively investigated. Here we experimentally demonstrate a graphene-based SPR biosensor. By
incorporating a graphene layer to the conventional gold thin film SPR structure, its biosensing sensitivity is significantly
increased. This is shown in a typical affinity biosensing experiment to measure the real-time binding kinetics of biotin-streptavidin.
In addition to higher sensitivity, we also obtain a much higher signal-to-noise ratio without the slightest
modification of the usual measurement setup. This implies that a considerably lower limit of detection can be made
possible with the novel structure. Moreover, our graphene-based SPR biosensors do not require sophisticated surface
functionalization schemes as in conventional SPR in order to function. Previous reports have also suggested that
graphene might effectively prevent non-specific binding of biomolecules on the sensor surface. With relatively simple
fabrication methods and large scalability, these combined distinctive advantages can enable future generation of high-performance