US 5,055,265 AGranted

Biological sensors

AssigneeAmersham International plc

InventorMartin F. Finlan

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Abstract

The present invention is drawn to a surface plasmon resonance (SPR) sensor in which the phenomenon of long-range surface plasmon resonance is used to develop a highly sensitive detector for use in biological, biochemical or general chemical testing. The sensor includes a laminar structure having of a high refractive index glass block, a membrane of dielectric material, a thin metal layer, and a sensitive layer. A sample to be tested is brought into contact with the sensitive layer. The refractive index of the dielectric layer and that of the layer (sensitive layer/sample) on the opposite side of the metallic layer should be equal, or nearly so, and the refractive index of the glass block should be higher than this so that total internal reflection takes place at the interface between the block and the membrane. Light from a laser source is totally internally reflected at this interface, and the strength of the reflected beam is monitored by a light detector. Provided conditions are correct, long-range SPR will take place which will sensitively alter the strength of the light in dependence upon the progress of the reaction between the sensitive layer and sample.

Claims23

Dependent claims

A sensor for use in biological, biochemical or chemical testing, said sensor comprising:

a structure comprising a block of material, a membrane of dielectric material disposed over a surface of said block, a layer of metallic material disposed over that surface of said membrane opposite said block, and a layer of sensitive material disposed over said metallic layer;
means for introducing onto the sensitive layer so as to react therewith a sample to be analyzed in which the index of refraction of the sample and/or said sensitive layer is equal or nearly equal to that of said membrane, and the index of refraction of the material of said block is higher than that of said membrane and the sample;
means for generating electromagnetic radiation that is transmittable through said block of material and for directing the radiation through said block at a location within said structure in a manner which causes long range surface plasmon resonance to occur and which causes the radiation to be internally reflected by said structure from said location;
and detecting means for monitoring radiation from said source which has been internally reflected within the structure and for detecting the characteristics of the resonance that are dependent upon the reaction between the sample and the sensitive layer.

1 more element

Dependencies are inferred from the claim text.