A series of bioluminescent (BL) readouts entitled “a portfolio of rainbow BL readouts,” that luminesces across the whole visible light range has been developed by AIST in collaboration with Professors N. Kitada, S. A. Maki at the University of Electro-Communications. These markers are commonly applicable for medical and environmental diagnostics and bioimaging.

It has been a long-term challenge to wavelength control of BL readouts upon detection of specific biomarkers in the medical and environmental diagnostics fields. Recently, BL is emerging in bioassays, cancer imaging, and other applications. However, natural BL is highly limited in the color variation. BL derived from marine organisms in particular mostly luminesces only in the range of blue to green. Then, the BL is easily absorbed by the hemoglobin in living subjects. As a result, the tissue permeability is poor, and optical cross-talks between the BL readouts easily occur.

A portfolio of rainbow BL readouts has been developed by combining an artificial luciferase of AIST origin (ALuc®, AIST trademark) with a series of BL substrates developed by the University of Electro-Communications. Some natural marine luciferases derived from marine organisms such as sea pansy are also applicable for the creation of diverse BL colors covering whole visible region.

This technology exemplifies a simultaneous imaging of multiple biomarkers only in animal cells. However, bioimaging in various animal models is another subject to be addressed in the future study. The researcher will improve the optical properties of the BL readouts, for example, the better chemical stability of the substrates and the stronger BL. The BL readouts with a wide color range are a great addition to the medical and environmental diagnostic fields.