Illumina BeadArray. Illumina BeadArray. The SAM contains 96 1.4-mm fiber-optic bundles (bottom left). Each bundle is an individual array consisting of 50,000 5-μm fiber-optic strands, each of which is chemically etched to create a microwell for a single bead (top left). The Sentrix BeadChips can assay 1 to 16 samples at a time on a silicon slide (bottom right) that has been processed to provide microwells for individual beads (top right). Both BeadArray platforms rely on 3-μm silica beads that randomly self-assemble (center). (Adapted from reference 53 with permission of the publisher. © 2009 BioTechniques.) Melissa B. Miller, and Yi-Wei Tang Clin. Microbiol. Rev. 2009; doi:10.1128/CMR.00019-09