title: Magneto-plasmonic biosensor with enhanced analytical response and stability.
abstract: We present novel solutions to surpass current analytic limitations of Magneto-Optical Surface Plasmon Resonance (MOSPR) assays, concerning both the chip structure and the method for data analysis. The structure of the chip is modified to contain a thin layer of Co-Au alloy instead of successive layers of homogeneous metals, as currently used. This alloy presents improved plasmonic and magnetic properties, yet a structural stability similar to Au-SPR chips, allowing for bioaffinity assays in saline solutions. Analyzing the whole reflectivity curve at multiple angles of incidence instead of the reflectivity value at a single incidence angle provides a high signal-to-noise ratio suitable for detection of minute analyte concentrations. Based on assessment of solutions with known refractive indices as well as of a model biomolecular interaction (i.e. IgG-AntiIgG) we demonstrate that the proposed structure of the MOSPR sensing chip and the procedure of data analysis allows for long-time assessment in liquid media with increased sensitivity over standard SPR analyses.
authors.affiliation: International Centre of Biodynamics, Intrarea Portocalelor 1B, Bucharest 060101, Romania.
authors.forename: Sorin
authors.initials: S
authors.lastname: David
authors.affiliation: International Centre of Biodynamics, Intrarea Portocalelor 1B, Bucharest 060101, Romania.
authors.forename: Cristina
authors.initials: C
authors.lastname: Polonschii
authors.affiliation: National Institule for Laser, Plasma and Radiation Physics, Atomistilor 409, Magurele 077125, Romania.
authors.forename: Catalin
authors.initials: C
authors.lastname: Luculescu
authors.affiliation: International Centre of Biodynamics, Intrarea Portocalelor 1B, Bucharest 060101, Romania.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Gheorghiu
authors.affiliation: International Centre of Biodynamics, Intrarea Portocalelor 1B, Bucharest 060101, Romania.
authors.forename: Szilveszter
authors.initials: S
authors.lastname: Gáspár
authors.affiliation: International Centre of Biodynamics, Intrarea Portocalelor 1B, Bucharest 060101, Romania; University of Bucharest, 4-12 Regina Elisabeta Blvd., Bucharest 030018, Romania. Electronic address: egheorghiu@biodyn.ro.
authors.forename: Eugen
authors.initials: E
authors.lastname: Gheorghiu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D060306:Magnetometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
keywords: Affinity biosensor; Angle-resolved surface plasmon resonance; Fixed-angle surface plasmon resonance; Magnetic alloys; Magneto-optic surface plasmon resonance; Surface plasmon resonance enhancement