Chemical. CAS 28643-80-3. Formula C40H67NaO11. MW 746.94. Nigericin is an antibiotic, used as a high affinity ionophore for monovalent cations such as H, K, Na, Pb2. It shows antibacterial Gram-positive, antifungal, antitumor and antiviral activity and disrupts membrane potential of mitochondria. It sprimary use is as a NLRP3 activator in inflammasome research.