XTT Protocols

The XTT Cell Viability Assay Protocol provides a safe, simple way to determine the amount of live cells by measuring in micro-plates the cellular response external factors. The XTT Protocol is preferable to the administering of the MTT Protocol, because it eliminates the usage of thymidine, a radioactive material, and provides reliable results that are easily reproduced.

Chemical Reaction

• The XTT Protocol utilizes tetrazolium salts to assay cell proliferation, cell viability and cytotoxicity. The XTT Protocol allows for rapid cell determination in micro-plates. The cleavage of the tetrazolium to formazon results from the reaction of the tetrazolium reductase system in the mitochondria of metabolically active cells.

XTT Protocol Components

• The administering of the XTT Protocol requires the presence of three testing components: the XTT Regent, the XTT Activator, and the XTT Working Solution. The XTT Regent must be stored at less than 20 degrees C. XTT Regent will capture precipitation during storage, and must be heated to 37 degrees C before use. XTT Activator must be stored at temperatures less than 20 derees C, and must be heated to 37 degrees C, until fully dissolved. Prior to testing, the XTT Working Solution must be prepared by combining the 5mL of XTT Reagent with 100uL of XTT Activator.

XTT Protocol Advantages

• There are several advantages for administering the XTT protocol, rather than utilizing radioactive labeling of the cellular DNA using thymidine. The XTT protocol is more sensitive, and eliminates the use of radioactive materials. The XTT protocol can be administered quickly, without requiring cell stabilization steps, and is recommended for high throughput assays, reducing cell loss and cell variation in results.