| abstract |
A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprises a light transmissive substrate, an array of surface plasmon resonant (SPR) elements mounted thereon, a light source arranged to direct light into the SPR elements, and a detector arranged to detect light transmitted through the SPR elements. The SPR elements may include a dielectric polystyrene sphere having a spherical diameter of about 770 nm with a gold coating layer about 150 nm thick. The interface between the SPR elements and the substrate forms a pinhole with a diameter less than the wavelength of the light directed into the elements to produce a near-field coupling mode within the micro-sized SPR elements. In specific embodiments, the pinhole diameter ranges between 150-200 nm. The SPR elements are contained within a molded PDMS chip that may incorporate micro-fluidic components, such as a pump and valves, to control flow of the test fluid across the SPR elements. A multi-channel sensor may be provided for detecting the presence of several targets with a single micro-chip sensor. In the multi-channel sensor collections of SPR elements are commonly functionalized to one of the several targets. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets. |