Firefly bioluminescent system is attracting widespread attention as an in vivo imaging tool. Recently, near-infrared (NIR) light (650~1000 nm) is a hot topic due to high living body permeability. Although many NIR fluorescence imaging tools are commercialy available, these are not self-luminescent.

We study the relationship between structure modification and the firefly luminescence wavelength, that the luciferase of Photinus pyralis (Ppy) was used. And we have succeeded in development of AkaLumine® which is a world's first near-infrared light in vivo imaging tool of bioluminescence. AkaLumine® is employed in in vivo imaging for mice. However, we wish AkaLumine® is used in larger animals such as marmoset and miniature pigs for in vivo imaging. We have subsequently developed a high solubility salt of AkaLumine®, TokeOni. The high solubility of TokeOni enables in vivo imaging in the previously mentioned larger animals. We have conducted imaging studies in miniature pig and we report its usability for in vivo imaging and the benefit it would provide to the greater scientific field.