title: APPLIED PHYSICS. Mid-infrared plasmonic biosensing with graphene.
abstract: Infrared spectroscopy is the technique of choice for chemical identification of biomolecules through their vibrational fingerprints. However, infrared light interacts poorly with nanometric-size molecules. We exploit the unique electro-optical properties of graphene to demonstrate a high-sensitivity tunable plasmonic biosensor for chemically specific label-free detection of protein monolayers. The plasmon resonance of nanostructured graphene is dynamically tuned to selectively probe the protein at different frequencies and extract its complex refractive index. Additionally, the extreme spatial light confinement in graphene—up to two orders of magnitude higher than in metals—produces an unprecedentedly high overlap with nanometric biomolecules, enabling superior sensitivity in the detection of their refractive index and vibrational fingerprints. The combination of tunable spectral selectivity and enhanced sensitivity of graphene opens exciting prospects for biosensing.
authors.affiliation: Institute of BioEngineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rodrigo
authors.affiliation: Institute of BioEngineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Odeta
authors.initials: O
authors.lastname: Limaj
authors.affiliation: Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Davide
authors.initials: D
authors.lastname: Janner
authors.affiliation: Institute of BioEngineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Dordaneh
authors.initials: D
authors.lastname: Etezadi
authors.affiliation: Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain. Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
authors.forename: F Javier
authors.initials: FJ
authors.lastname: García de Abajo
authors.affiliation: Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain. Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
authors.forename: Valerio
authors.initials: V
authors.lastname: Pruneri
authors.affiliation: Institute of BioEngineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. hatice.altug@epfl.ch.
authors.forename: Hatice
authors.initials: H
authors.lastname: Altug
mesh_terms: D015374:Biosensing Techniques; D006108:Graphite; D007259:Infrared Rays; D049329:Nanostructures; D011506:Proteins / Q000032:analysis*; D013055:Spectrophotometry, Infrared / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*; D014732:Vibration
chemical_list: D011506:Proteins; D006108:Graphite