TokeOni is a luciferin analog that exhibits near-infrared emission (λmax = 675 nm, Figure 1).
TokeOni emits light upon reacting with firefly luminescent enzymes such as Fluc and Akaluc. Thus, it can be used for imaging luciferase-expressing cells, as well as for reporter assays involving luciferase gene transfer.
*TokeOni was developed by Professor Maki of the University of Electro-Communications. Our company has achieved mass production.

• Near-infrared luminescence is advantageous for observation of deep tissues due to its high biological penetration ability
• Can be used in place of D-luciferin in Fluc systems such as Luc2
• Using the specialized enzyme Akaluc, measurement for deep tissue imaging is more sensitive than D-luciferin×Fluc (Firefly BLI (Bio-Luminescence Imaging))

• 1. Even a small number of cells that could not be detected with Firefly-BLI, can be visualized

  Luc2- and Akaluc-expressing cells were introduced into mice by tail vein injection, at 10 cells/100 cells each.
  D-luciferin and TokeOni were then administered by tail vein injection. (Figure 2)
  Both groups of 10 cells and 100 cells were barely visible with Firefly-BLI, but clearly detectable with Aka-BLI.

  

  Figure 2. Visualization of luciferase-expressing cells: 10 cells (left)/100 cells (right)
  (Images provided by Dr. Takahiro Kuchimaru, Associate Professor, Jichi Medical University)

• 2. Actualizing ultra-sensitive brain imaging

  While imaging of the brain with Firefly-BLI is extremely difficult due to the influence of the blood-brain barrier (BBB), Aka-BLI has a detection sensitivity of approximately 1,400 times more than the former, making it highly sensitive for brain imaging. In addition, observing moving images in real time is possible (Figure 3).

  

  Figure 3. Brain imaging of two freely moving mice
  (Image provided by Dr. Satoshi Iwano, RIKEN)

• 3. Real-time observation of marmoset brain is possible

  Brain visualization with Aka-BLI has been achieved in not only mice and other small animals, but also in small primates such as marmosets (Figure 4).
  Here, both the actual moving marmoset and the emission from its brain can be detected at the same time.

  

  Figure 4. Brain imaging of freely moving marmoset
  (Image provided by Dr. Satoshi Iwano, RIKEN)

TokeOni should be prepared in water or physiological saline when administering to animals.
It can emit light at sites where luminescent enzymes (Luc2 and Akaluc) are present.

*Cautionary points
When TokeOni is introduced into a living body, it is often confirmed that the liver autofluoresces. There are individual differences depending on the animal, but please be careful when measuring the emission brightness near the liver.

Information on safe handling and storage of TokeOni, and its chemical composition will be provided through the “SDS (Safety Data Sheet).”