RESUMEN
In this paper, we describe wafer-scale fabrication and characterization of plasmonic chips-containing different sizes and spacings of metallic micro- and nanoline structures-using deep UV lithography. Using a high dose (25 mJ cm( - 2)) and a proper lift-off process, feature sizes as small as 25 nm are obtained. Moreover, we study the dependence of surface plasmon resonance on the angle of incidence and wavelength for different micro- and nanoline size and spacing values, yielding localized to quasi-propagative plasmonic behaviors. Rigorous coupled wave analysis (RCWA) techniques are employed to numerically confirm these experimental observations. Finally, the refractive index of media around the SPRI sensor chips is varied, showing the angulo-spectral regions of higher sensitivity for each type of structure.
Asunto(s)
Cristalización/métodos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Resonancia por Plasmón de Superficie/métodos , Sustancias Macromoleculares/química , Sustancias Macromoleculares/efectos de la radiación , Ensayo de Materiales , Conformación Molecular/efectos de la radiación , Nanoestructuras/efectos de la radiación , Tamaño de la Partícula , Dosis de Radiación , Propiedades de Superficie/efectos de la radiación , Rayos UltravioletaRESUMEN
In this paper, we study the performances of nanosensors based on Localized Surface Plasmon Resonance in the context of biological sensing. We demonstrate the sensitivity and the selectivity of our designed nanosensors by studying the influence of the concentration of Streptavidin on the shift of Localized Surface Plasmon Resonance wavelength. In addition, to study the detection of biomolecules on a single Au nanoparticle, we used a Scanning Near-field Optical Microscope. These results represent new steps for applications in biological research and medical diagnostics.
Asunto(s)
Técnicas Biosensibles/métodos , Biotina/química , Nanopartículas del Metal/química , Nanotecnología/métodos , Estreptavidina/química , Resonancia por Plasmón de Superficie , Oro/química , Microscopía Electrónica de Rastreo , Unión Proteica , Sensibilidad y Especificidad , Plata/químicaRESUMEN
The paper shows how polysiloxane particles encapsulating fluorophores can be successfully used to detect biotin-streptavidin binding by two types of technique. After functionalization of the particles by streptavidin, the fixation of the biomolecule can indeed be detected by a shift of the localized surface plasmon resonance of the biotinylated gold dots used as substrate and by the luminescence of the fluorophores evidenced by scanning near-field optical microscopy. The development of particles allowing such a double detection opens a route for increasing the reliability of biological detection and for multi-labelling strategies crossing both detection principles.