5-Ethynyl-2'-deoxyuridine

5-Ethynyl-2'-deoxyuridine (EdU) is a nucleoside analog of thymidine that is used to monitor de novo DNA synthesis through click chemistry.{32475,32476} Like 5-bromo-2’-deoxyuridine (BrdU; Item No. 15580), EdU is incorporated into DNA during active DNA synthesis. It can then be detected using a fluorescent azide probe and copper catalysis using 1,3-dipolar cycloaddition.{32476} Modified nucleosides, including EdU, can be cytotoxic when added to cells for prolonged periods.{32477}