A fluorescent one-dimensional photonic crystal for label-free biosensing based on BLOCH surface waves

• Published in: Sensors (Basel, Switzerland) Switzerland), 2013-02, Vol.13 (2), p.2011-2022
• Main Authors: Frascella, Francesca, Ricciardi, Serena, Rivolo, Paola, Moi, Valeria, Giorgis, Fabrizio, Descrovi, Emiliano, Michelotti, Francesco, Munzert, Peter, Danz, Norbert, Napione, Lucia, Alvaro, Maria, Bussolino, Federico
• Format: Article
• Language: English
• Subjects: Biosensing Techniques - methods; bragg mirrors; Crystallization; Electronic mail systems; fluorescence; Glass substrates; GTP-Binding Proteins - metabolism; label-free sensing; Lasers; multilayers; Optics; Photons; Protein Binding; Sensors; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Staining and Labeling; surface electromagnetic waves; Surface Properties
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s130202011

A one-dimensional photonic crystal (1DPC) based on a planar stack of dielectric layers is used as an optical transducer for biosensing, upon the coupling of TE-polarized Bloch Surface Waves (BSW). The structure is tailored with a polymeric layer providing a chemical functionality facilitating the covalent binding of orienting proteins needed for a subsequent grafting of antibodies in an immunoassay detection scheme. The polymeric layer is impregnated with Cy3 dye, in such a way that the photonic structure can exhibit an emissive behavior. The BSW-coupled fluorescence shift is used as a means for detecting refractive index variations occurring at the 1DPC surface, according to a label-free concept. The proposed working principle is successfully demonstrated in real-time tracking of protein G covalent binding on the 1DPC surface within a fluidic cell.