Patent ID: 7314749

Claim:
A sensing element for use in a light diffraction assay for detecting the presence or absence of at least one analyte, comprising: a substrate including a planar surface and analyte-specific recognition binding elements laid out on said planar surface in a pre-selected pattern such that when analytes are present in an assay they bind to said analyte-specific recognition binding elements, said pre-selected pattern being configured so that under illumination by a beam of light a diffraction pattern is produced having at least one diffraction spot spaced from said beam of light and having a sufficient amount of intensity of said diffraction pattern being located at said at least one diffraction spot to indicate presence of analytes bound to said analyte specific recognition binding elements, said pre-selected pattern excluding said analyte-specific recognition binding elements arrayed in parallel straight lines of substantially equal width spaced evenly from each other, or in a periodic array of circles, said pattern of analyte-specific recognition binding elements being a first pattern for binding first analytes present in said medium, and at least a second pattern of analyte-specific recognition binding elements for binding second analytes present in said medium.