Microvessels, microparticles, and methods of manufacturing and using the same

A method of reading a plurality of encoded microvessels used in an assay for biological or chemical analysis, the method comprising:

• providing a plurality of encoded microvessels, the microvessels comprising a respective microbody and a reservoir core in the microbody, wherein the reservoir core is holding a substance for performing the assay for biological or chemical analysis, the substance having an optical characteristic, the microbody comprising a solid material that forms one or more walls that extend around the reservoir core, wherein the solid material is transparent to the optical characteristic of the substance within the reservoir core, wherein the solid material includes an identifiable code associated with the substance, wherein each of the microbodies of the plurality of microvessels has a common elongated structure and each of the reservoir cores of the plurality of microvessels has a common shape, the identifiable codes comprising gratings with a superposition of different predetermined regular periodic variations of an index of refraction disposed along the elongated structure of each of the microbodies;
• separating at least some of the individual microvessels of the plurality of encoded microvessels into individual compartments of a holder such that each of the compartments has only one of the microvessels therein;
• and
• detecting the corresponding identifiable codes of the microvessels when the microvessels are held in the compartments.