Immunoassay using optical interference detection

[2. The apparatus of claim 1 wherein the predetermined pattern is formed by a plurality of stripes of antiligand material, each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[3. The apparatus of claim 2 wherein the plurality of stripes of antiligand material is formed by antiligand material supported on a flat continuous surface.]

[4. The apparatus of claim 1 wherein the spacial array if formed by antiligand material supported on a grooved surface forming an interference grating.]

[5. The apparatus of claim 1 including ligand attached to carrier particles which compete with the unknown ligand for binding sites on the antiligand material.]

[6. The apparatus of claim 1 including antiligand attached to carrier particles to cause a binding reaction with the ligand for increasing the signal representative of the binding reaction.]

[7. The apparatus of claim 1 wherein the optical detector is on the same side of the pattern as the source of optical radiation to detect backscattered, or reflected, radiation.]

[8. The apparatus of claim 1 wherein the optical detector is on the opposite side of the pattern as the source of optical radiation to detect forward scattered, or transmitted, radiation.]

[9. The apparatus of claim 1 wherein the ligand is attached to carrier particles which are biological entities, such as cells.]

[10. The apparatus of claim 9 wherein the ligand on the carrier particle is naturally occurring.]

[11. The apparatus of claim 1 wherein the pattern is formed by deactivating microscopic sections of an initially uniform layer of an antiligand supported on a continuous surface.]

[12. The apparatus of claim 11 in which the deactivated sections consist of a plurality of stripes each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[14. The apparatus of claim 12 wherein the pattern is formed by a plurality of stripes of antibody material, each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[15. The apparatus of claim 13 wherein the pattern of antibody material is formed by antibody material supported on a flat continuous surface.]

[16. The apparatus of claim 13 wherein the spacial array of antibody is formed by antibody material supported on a grooved surface forming an interference grating.]

[17. The apparatus of claim 13 including antigen attached to carrier particles which competes with the unknown antigen for binding sites on the antibody material.]

[18. The apparatus of claim 13 including antibody attached to carrier particles to cause a binding reaction with the antigen for increasing the signal representative of the binding reaction.]

[19. The apparatus of claim 13 wherein the optical detector is on the same side of the pattern as the source of optical radiation to detect backscattered, or reflected, radiation.]

[20. The apparatus of claim 13 wherein the optical detector is on the opposite side of the pattern as the source of optical radiation to detect forward scattered, or transmitted radiation.]

[21. The apparatus of claim 13 wherein the antigen is attached to carrier particles which are biological entities.]

[22. The apparatus of claim 21 wherein the antigen on the carrier particle is naturally occurring.]

[23. The apparatus of claim 13 wherein the pattern is formed by deactivating microscopic sections of an initially uniform layer of an antibody supported on a continuous surface.]

[24. The apparatus of claim 23 in which the deactivated sections consist of a plurality of stripes each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[26. The method of claim 25 wherein the predetermined pattern is formed by a plurality of stripes of antiligand material, each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[27. The method of claim 26 wherein the plurality of stripes of antiligand material is formed by

• antiligand material supported on a flat continuous surface.]

[28. The method of claim 25 wherein the the spacial pattern of antiligand material is formed by antiligand material supported on a grooved surface forming an interference grating.]

[29. The method of claim 25 including ligand attached to carrier particles which competes with the unknown ligand for binding sites on the antiligand material.]

[30. The method of claim 25 including antiligand attached to carrier particles to cause a binding reaction with the ligand for increasing the signal representative of the binding reaction.]

[31. The method of claim 25 wherein the optical detection is on the same side of the pattern as the source of optical radiation to detect backscattered, or reflected, radiation.]

[32. The method of claim 25 wherein the optical detection is on the opposite side of the pattern as the source of optical radiation to detect forward scattered, or transmitted, radiation.]

[33. The method of claim 25 wherein the ligand is attached to carrier particles which are biological entities.]

[34. The method of claim 33 wherein the ligand on the carrier particle is naturally occurring.]

[35. The method of claim 25 wherein the pattern is formed by deactivating microscopic sections of an initially uniform layer of an antiligand.]

[36. The method of claim 35 in which the deactivated sections consist of a plurality of stripes each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[38. The method of claim 37 wherein the regular pattern is formed by a plurality of stripes of antibody material, each stripe having a width of microscopic dimensions and separated from each other by a constant microscopic dimension.]

[39. The method of claim 38 wherein the plurality of stripes of antibody material is formed by antibody material supported on a flat continuous surface.]

[40. The method of claim 37 wherein the spacial pattern of antibody material is formed by antibody material supported on a grooved surface forming an interference grating.]

[41. The method of claim 37 including antigen attached to carrier particles which competes with the unknown antigen for binding sites on the antigen material.]

[42. The method of claim 37 including antibody attached to carrier particles to cause a binding reaction with the antigen for increasing the signal representative of the

• binding reaction.]

[43. The method of claim 37 wherein the optical detection is on the same side of the pattern as the source of optical radiation to detect backscattered, or reflected, radiation.]

[44. The method of claim 37 wherein the optical detection is on the opposite side of the pattern as the source of optical radiation to detect forward scattered, or transmitted, radiation.]

[45. The method of claim 37 wherein the antigen is attached to carrier particles which are biological entities.]

[46. The method of claim 45 wherein the antigen on the carrier particle is naturally occurring.]

[47. The method of claim 37 wherein the pattern is formed by deactivating microscopic sections of an initially uniform layer of an antiligand.]

[48. The method of claim 47 in which the deactivated sections consist of a plurality of stripes each stripe having a width of microscopic dimensions and separated from each

• other by a constant microscopic dimension.]

A flat immunoassay substrate having a uniform coating thereon, the uniform coating comprising an immunochemical optical interference pattern of microscopic dimensions of alternating areas of an active and deactivated member of a binding pair consisting of ligand and antiligand, the uniform coating having effectively uniform scattering properties and having a minimum scattering intensity at Bragg angles .theta..sub.s, the pattern of alternating areas forming an optical interference grating with a detectable scattering intensity at Bragg angles .theta..sub.s if the one member of the binding pair is bound to the other member of the binding

• pair.