Immunoassay using optical interference detection

Apparatus for producing an output signal in accordance with a binding reacton between an antibody and an antigen, including,

• a spatial array of antibody having a plurality of elements of microscopic dimensions to form a predetermined pattern,
• antigen located in solution adjacent to the spatial array of antibody to interact with the antibody in a binding reaciton in the pattern,
• an incident source of optical radiation and with the source being substantially coherent and monochromatic and directed to the pattern for illuminating the plurality of elements of the spatial array for producing an optical interference pattern at particular scattering angles in accordance with the modulation of the optical properties of the predetermined antibody pattern due to the binding reaction, and
• one or more detectors located near the pattern at one or more of the particular scattering angles to intercept the radiation and produce an output signal in accordance with the binding reaction.

A method for providing an optical detection of a binding reaction between a ligand and an antiligand, including the following steps,

• forming a predetermined pattern having a spatial array having a plurality of elements of microscopic dimensions of antiligand material,
• providing ligand material to interact with the spatial array of antiligand material to produce a binding reaction between the ligand and the antiligand in the periodic pattern,
• directing optical radiation including energy of at least one wavelength to the pattern for illuminating the plurality of elements of the spatial array to produce scattering of the energy from the pattern following the physical principle of constructive optical interference in accordance with the binding reaction and with a strong scattering intensity at one or more particular scattering angles, and
• detecting the strong scattering intensity at one or more of the particular scattering angles to produce a signal representative of the binding reaction.

A method for producing an output signal in accordance with a binding reaction between an antibody and an antigen, including the following steps,

• providing a spatial array of antibody having a plurality of elements of microscopic dimensions to form a predetermined pattern,
• locating antigen in solution adjacent to the spatial array of antibody to interact with the antibody in a binding reaction in the pattern,
• directing substantially coherent and monochromatic optical radiation to the pattern for illuminating the plurality of elements of the spatial array for producing scattering from the pattern at particular scattering angles due to optical interference in accordance with the binding reaction, and
• detecting the scattered radiation to produce an output signal in accordance with the binding reaction.