Description
How Sensitive Is the CellTiter-Glo® 3D Assay Compared to Other Viability Assays?
The CellTiter-Glo® 3D Assay produces luminescent signals that are orders of magnitude above background in 3D microtissue models—a substantially larger signal-to-noise margin than either fluorometric or colorimetric alternatives. In direct comparison using InSphero Insight™ human liver microtissues (~250μm diameter), alamarBlue® and MTT generated signals only modestly above their no-cell controls, while the CellTiter-Glo® 3D Assay produced a robust, high-contrast readout. The CellTiter-Glo® 3D Assay also completed the assay in 30 minutes, compared to 3 hours for alamarBlue® and 8 hours for MTT.
Comparison data: InSphero Insight™ human liver microtissues (~250μm); HCT116 colon cancer cells seeded into an InSphero GravityPLUS™ 96-well hanging-drop platform and grown to generate ~340μm spheroids.All microtissues assayed per manufacturer protocols.
The superior sensitivity of ATP-based luminescence over colorimetric or fluorometric methods in 3D models reflects two compounding advantages: the luciferase-based assay detects ATP directly with high signal amplification, and CellTiter-Glo® 3D’s enhanced lysis buffer ensures complete ATP recovery from throughout the spheroid. Fluorometric assays like alamarBlue® depend on metabolic reduction rates that are lower in the hypoxic and nutrient-limited interior of 3D spheroids, further reducing their signal in the models where accurate measurement matters most.
