Diffraction grating-based encoded microparticle assay stick

Abstract

An assay stickincludes a transparent reaction vessel or tubehaving one or more microbeadsdisposed therein. The microbeadshave a plurality of unique identification digital codes based on a diffraction gratingdisposed therein that are detected when illuminated by incident light. The incident lightmay be directed transversely onto the side or onto an end of the tubewith a narrow band (single wavelength) or multiple wavelength source, in which case the code is represented by a spatial distribution of light or a wavelength spectrum, respectively. The assay stickmay be reused or disposed upon completion of the assay. Alternatively, the beads may be attached to a strip or planar surface. The encoded beads can also provide traceability, quality-control, and authenticity of each beadto its source and/or to the chemistry on each bead. Also, the low sample volume of the assay stick allows for faster reactions and better sensitivity.