ATP-Red 1 is primarily used in biological research as a fluorescent probe to detect and measure ATP (adenosine triphosphate) levels in living cells. Its application is crucial in studying cellular energy metabolism, as it allows researchers to visualize and quantify ATP dynamics in real-time. This is particularly useful in understanding processes like mitochondrial function, cell viability, and stress responses. Additionally, ATP-Red 1 is employed in drug discovery and toxicology studies to assess the impact of compounds on cellular energy production. Its high sensitivity and specificity make it a valuable tool in both basic and applied biomedical research.