title: Differentiating surface and bulk interactions in nanoplasmonic interferometric sensor arrays.
abstract: Detecting specific target analytes and differentiating them from interfering background effects is a crucial but challenging task in complex multi-component solutions commonly encountered in environmental, chemical, biological, and medical sensing applications. Here we present a simple nanoplasmonic interferometric sensor platform that can differentiate the adsorption of a thin protein layer on the sensor surface (surface effects) from bulk refractive index changes (interfering background effects) at a single sensing spot, exploiting the different penetration depths of multiple propagating surface plasmon polaritons excited in the ring-hole nanoplasmonic sensors. A monolayer of bovine serum albumin (BSA) molecules with an effective thickness of 1.91 nm is detected and differentiated from a 10(-3) change in refractive index unit for the bulk solution. The noise level of the retrieved real-time sensor output compares favorably with that of traditional prism-based surface plasmon resonance sensors, but is achieved using a significantly simpler collinear transmission geometry and a miniaturized sensor footprint.
authors.affiliation: Electrical and Computer Engineering Department, Lehigh University, Bethlehem, PA 18015, USA. bez210@lehigh.edu fjb205@lehigh.edu.
authors.forename: Beibei
authors.initials: B
authors.lastname: Zeng
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Gao
authors.forename: Filbert J
authors.initials: FJ
authors.lastname: Bartoli
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007368:Interferometry / Q000295:instrumentation*; D036103:Nanotechnology / Q000295:instrumentation*; D025941:Protein Interaction Mapping / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014159:Transducers
chemical_list: D012710:Serum Albumin, Bovine