title: Angularly resolved ellipsometric optical biosensing by means of Bloch surface waves.
abstract: In label-free biosensing, a continuous improvement of the limit of detection is necessary to resolve the small change of the surface refractive index produced by interacting biomolecules at a very small concentration. In the present work, optical sensors based on one-dimensional photonic crystals supporting Bloch surface waves are proposed and adopted for label-free optical biosensing. We describe the implementation of an angularly resolved ellipsometric optical sensing scheme based on Bloch surface waves sustained by tantala/silica multilayers. The angular operation is obtained using a focused beam at fixed wavelength and detection of the angular reflectance spectrum by means of an array detector. The results show that the experimental limit of detection for a particular photonic crystal design is 6.5 × 10(-7) refractive index units (RIU)/Hz(1/2) and further decrease could be obtained. For the first time, we report on the practical application of this technique to a cancer biomarker protocol that aims at the detection of a specific glycoprotein (angiopoietin 2) involved in angiogenesis and inflammation processes.
authors.affiliation: Department of Basic and Applied Science for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Sinibaldi
authors.forename: Aleksei
authors.initials: A
authors.lastname: Anopchenko
authors.forename: Riccardo
authors.initials: R
authors.lastname: Rizzo
authors.forename: Norbert
authors.initials: N
authors.lastname: Danz
authors.forename: Peter
authors.initials: P
authors.lastname: Munzert
authors.forename: Paola
authors.initials: P
authors.lastname: Rivolo
authors.forename: Francesca
authors.initials: F
authors.lastname: Frascella
authors.forename: Serena
authors.initials: S
authors.lastname: Ricciardi
authors.forename: Francesco
authors.initials: F
authors.lastname: Michelotti
mesh_terms: D042702:Angiopoietin-2 / Q000737:chemistry / Q000276:immunology; D000818:Animals; D000906:Antibodies; D014408:Biomarkers, Tumor; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007834:Lasers; D051379:Mice; D061848:Optical Imaging / Q000295:instrumentation* / Q000379:methods*; D055095:Optics and Photonics; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D012031:Refractometry
chemical_list: C586513:ANGPT2 protein, human; D042702:Angiopoietin-2; D000906:Antibodies; D014408:Biomarkers, Tumor; D011994:Recombinant Proteins