Biological sensors
First Claim
1. A sensor for use in biological, biochemical or chemical testing, said sensor comprising:
- an optical waveguide having an input end and an output end and along which radiation may propagate by means of internal reflections off its internal surfaces,a source of electromagnetic radiation whose output is applied to the input end of said optical waveguide, andwherein said output end of the optical waveguide is cut off at an angle to its axis to provide a sloping end face,wherein said radiation is input to the waveguide as a focussed beam so that the beam is incident at said end face as a spread of angles, andwherein the angle of the sloping end face is such as to (1) cause the incident beam to be totally internally reflected at said face, and (2) cause the thus-reflected beam to be incident on the wall of the waveguide at an angle sufficiently great for it to exit from the waveguide without being subject to further internal reflection,means for monitoring the radiation from said source which is internally reflected at said face,a layer of metallic material applied to said sloping face,a layer of sensitive material applied to the metallic layer, andmeans for introducing onto the sensitive layer so as to react therewith a sample to be analyzed,the arrangement being such that the aforesaid spread of radiation incident at said face of the optical waveguide is such as to include that angle at which surface plasmon resonance occurs, and allows the changing characteristics of the resonance to be monitored, which characteristics, as detected by said monitoring means, are dependent upon the reaction between the sample and the sensitive layer.
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Accused Products
Abstract
A biological sensor which utilizes the phenomenon of surface plasmon resonance to detect the refractive index change which occurs when two components--for example antibody and corresponding antigen--react with one another. Surface plasmon resonance takes place at the sloping exit surface of an optical waveguide such as a fiber optic 23. The input end of fiber optic 12 is connected to a light source 12. A layer 25 of metal is applied to the sloping exit surface so as to cause total internal reflection of the light proceeding down the fiber optic. Reflected light is detected by a detector 13. A sensitive, for example antibody, layer 26 is applied to the metal layer. Sample (not shown) reacts with layer 26 in such a way that the refractive index changes. Provided conditions are correct, this variation in refractive index can be monitored in detector 13 by virtue of the surface plasmon resonance which occurs in the area of total internal reflection.
85 Citations
15 Claims
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1. A sensor for use in biological, biochemical or chemical testing, said sensor comprising:
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an optical waveguide having an input end and an output end and along which radiation may propagate by means of internal reflections off its internal surfaces, a source of electromagnetic radiation whose output is applied to the input end of said optical waveguide, and wherein said output end of the optical waveguide is cut off at an angle to its axis to provide a sloping end face, wherein said radiation is input to the waveguide as a focussed beam so that the beam is incident at said end face as a spread of angles, and wherein the angle of the sloping end face is such as to (1) cause the incident beam to be totally internally reflected at said face, and (2) cause the thus-reflected beam to be incident on the wall of the waveguide at an angle sufficiently great for it to exit from the waveguide without being subject to further internal reflection, means for monitoring the radiation from said source which is internally reflected at said face, a layer of metallic material applied to said sloping face, a layer of sensitive material applied to the metallic layer, and means for introducing onto the sensitive layer so as to react therewith a sample to be analyzed, the arrangement being such that the aforesaid spread of radiation incident at said face of the optical waveguide is such as to include that angle at which surface plasmon resonance occurs, and allows the changing characteristics of the resonance to be monitored, which characteristics, as detected by said monitoring means, are dependent upon the reaction between the sample and the sensitive layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification