Yasutero URANO and colleagues have synthesized a group of dyes exhibiting a short absorption wavelength of about 80 nm while maintaining fluorescence by becoming acidic. The dyes exhibited high stability on light irradiation. Furthermore, by changing the chemical structure, the fluorescence color could be changed from deep red to near infrared light in response to pH changes. When intravenously administered to subcutaneous tumor model mice, the average pH of the tumor tissue was 6.9 whereas in the normal tissue it was 7.3. The authors expect that these pH-sensitive fluorescent pigments can help to elucidate various biological phenomena related to pH with high spatiotemporal resolution.

JST news release, April 25, 2018