A joint research team from Hokkaido University Graduate School and RIKEN has successfully developed a fluorescent dye for medical applications of shortwave infrared fluorescence imaging. This makes it possible to observe the inside of the body while it is still alive.
The light we normally see (visible light) cannot pass through living tissues, but short-wave infrared (900-1400 nm) fluorescence is said to be able to obtain information deep within living organisms because it is less absorbed and scattered by tissues. Ru. There is no radiation exposure, and it is expected to be applied to non-invasive imaging diagnosis of human breast cancer. However, a highly safe short-wave infrared fluorescent dye that could be used in medical applications had not been developed.
This time, the joint research team has successfully synthesized analogs ICG-C9 and ICG-C11, which emit short-wave infrared fluorescence, based on indocyanine green (ICG), the only compound approved for use in humans. We have also developed shortwave infrared fluorescent labeling agents based on ICG, ICG-C9, and ICG-C11. This has made it easier to modify biomolecules such as antibodies with short-wave infrared dyes, making it possible to image breast cancer cells while they are still alive.
This enables multicolor shortwave infrared fluorescent molecular imaging of breast cancer tumors in living mice using antibodies modified with ICG, ICG-C9, and ICG-C11 dyes, and antibodies modified with ICG and ICG-C11. We demonstrated that the disappearance of breast cancer tumors using cancer drugs can be observed using two-color shortwave infrared fluorescence.
Furthermore, we succeeded in long-term imaging of breast cancer tumors. Breast cancer tumors were labeled with an anticancer drug conjugated with ICG-C9, and shortwave infrared fluorescence imaging was performed. As a result, it was confirmed non-invasively that the tumor size of breast cancer tumors treated with anti-cancer drugs was reduced to 38/1 in 12 days.
This development of cyanine-based short-wave infrared fluorescent dyes is expected to accelerate medical applications such as optical diagnosis of cancer using short-wave infrared fluorescence imaging.
