NCTR Scientist developing custom microarray. A microarray is a multiplex lab-on-a-chip. It is a 2D array on a solid substrate (usually a glass slide or silicon thin-film cell) that assays large amounts of biological material using high-throughput screening methods. The National Center for Toxicological Research (NCTR) is FDA's internationally recognized research center. The unique scientific research expertise of NCTR is critical in supporting FDA product centers and their regulatory science roles. NCTR, in partnership with researchers from government, academia, and industry, develops, refines, and applies current and emerging technologies to improve safety evaluations of FDA-regulated products.