Widely used in bioluminescence imaging, D-Luciferin sodium salt serves as a substrate for the enzyme luciferase, enabling real-time visualization of biological processes in live animals. It is essential in preclinical research, particularly in oncology, where tumor growth and metastasis are monitored using luciferase-expressing cancer cells. Upon administration, D-Luciferin crosses cell membranes and, in the presence of oxygen and ATP, reacts with luciferase to emit light that can be detected by sensitive imaging systems like IVIS. This allows researchers to track gene expression, protein-protein interactions, and the effectiveness of therapeutic agents non-invasively. It is also employed in microbiology to monitor bacterial load and infection progression in animal models. Due to its high sensitivity and low background signal, D-Luciferin is a key tool in molecular and cellular imaging studies.