Polarization interferometry (PI) techniques, which are able to improve surface plasmon resonance (SPR) sensing performance and reduce restrictions on allowable parameters of SPR-supporting metal films, have been experimentally realized only in SPR sensors using monochromatic light as a source. Wavelength-interrogation SPR sensors modulated by PI techniques have not been reported due to the wavelength-sensitive characterization of PI phase compensators. In this work we develop a specially designed rhombic prism for phase compensating which is totally insensitive to wavelength. For the first time we successfully apply PI technique to a wavelength-interrogation SPR imager. This imager is able to offer two-dimensional imaging of the whole array plane. As a result of PI modulation, resolutions of 1.3×10−6 refractive index unit (RIU) under the normal condition and 3.9×10−7 RIU under a more time-consuming condition are acquired. The application of this imager was demonstrated by reading microarrays for identification of bacteria, and SPR results were confirmed by means of fluorescence imaging.
SPR sensors have become a high sensitive and label free method for characterizing and quantifying chemical and
biochemical interactions. However, the relations between the SPR refractive index response and the property (such as
concentrations) of biochemical probes are still lacking. In this paper, an experimental study on the SPR responses of
varies concentrations of Legionella pneumophila mip DNA probes is presented. We developed a novel two-dimensional
SPR sensing technique-parallel scan spectral SPR imaging-to detect an array of mip gene probes. This technique
offers quantitative refractive index information with a high sensing throughput. By detecting mip DNA probes with
different concentrations, we obtained the relations between the SPR refractive index response and the concentrations of
mip DNA probes. These results are valuable for design and developing SPR based mip gene biochips.
In this paper, a new parallel scan spectral surface plasmon resonance (SPR) 2D sensing system is presented. With a lineshaped
light illumination, an image acquired with area CCD detector provides both SPR wavelength information and 1D
spatial distribution. Thus, 2D distribution of refractive index of the entire sensing plane can be obtained with 1D optical
line parallel scan. A refractive index distribution model and a manually dotted DNA array are measured with this system.
The technology shows advantages of both high sensitivity and high throughput in these results, and could have potential
applications in biochips analysis.
In a SPR sensor, a glass slide is coated with a metal film, whose thicknesses, density and dielectric constant deadly affect
the measurement sensitivity and precision in bio-detection. The optimum thickness of gold film used in SPR is between
40nm and 50nm without adhesive film, according to calculations based on multilayer reflection model cited in large
numbers of literatures. But experimental study on the optimum film parameters are still lacking attribute to the limitation
of film coating technology and high-precision thickness measurement technology. The optimum gold film thickness is
not 45nm observed in our SPR bio-detection, and the property of adhesive film which is needed for enhancing the
adhesion of metal film affects the SPR responsive bandwidth and minimum reflectivity. The experiment study on the
sensor gold film and the property of adhesive film for SPR sensor are described in this paper using high precision SPR
detection system, X-ray diffraction and magnetron sputtering technology. The optimum thickness for single gold film is
44nm and is 42nm for gold film with 2.4nm Cr adhesive layer. A new estimating factor is proposed to evaluate the
quality and resolution of metallic film.
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