The NIH/NIEHS, with NCATS, intends to award a sole-source firm-fixed-price purchase order to Promega Corporation for Promega assay reagents supporting Complement-ARIE mechanistic toxicology research. The reagents are needed to measure cell viability, liver injury/function, oxidative stress, antioxidant responses, and cellular bioenergetics in human 3D microphysiological systems, complementing cell painting and omics endpoints. The Government has determined Promega is the only identified source capable of meeting the specialized reagent combination, detection technology, and compatibility requirements, though responsible sources may submit quotations demonstrating ability to meet all requirements. Delivery is required by September 25, 2026, to NIEHS, Rall Building 101, Laboratories E144-146, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709.