A synthetic luciferin improves bioluminescence imaging in live mice

The synthetic firefly luciferase substrate CycLuc1 offers brighter bioluminescence and improved imaging in mouse models at lower doses than the standard D-luciferin. Firefly luciferase is the most widely used optical reporter for noninvasive bioluminescence imaging (BLI) in rodents. BLI relies on the ability of the injected luciferase substrate D-luciferin to access luciferase-expressing cells and tissues within the animal. Here we show that injection of mice with a synthetic luciferin, CycLuc1, improves BLI with existing luciferase reporters and enables imaging in the brain that could not be achieved with D-luciferin.