Imaging discovery could accelerate drug development
Posted: 27 February 2025 | Catherine Eckford (European Pharmaceutical Review) | No comments yet
The organic fluorophore’s super-photostability enables tracking of previously undetectable biological processes hindered with traditional fluorescent dyes.
Researchers at Pohang University of Science and Technology (POSTECH), South Korea, have developed a super-photostable organic dye. The discovery “sets a new benchmark for organic fluorophores”, Professor Young-Tae Chang explained, providing potential applications in broad areas such as drug development and cellular imaging.
Single-molecule imaging uses fluorescent markers to track proteins with precision. However, one challenge for current organic fluorophores is low photostability, the team stated.
For instance, the loss of fluorescence during extended light exposure (photobleaching) makes tracking proteins inside cells or monitoring intricate biological processes for long periods a challenge.
The team discovered the ultra-photostable fluorescent molecule Phoenix Fluor 555 (PF555) during single-molecule imaging, due to the photoblueing phenomenon. This structure was identified using mass spectrometry and nuclear magnetic resonance analysis, they explained.
Advantages of the highly photostable organic fluorophore
PF555 is an ultra-stable organic fluorophore unlike any previously reported. It will allow researchers to observe biological phenomena that were once restricted by time limitations”
In their study, the researchers could track the complete process of epidermal growth factor receptor (EGFR)’s endocytosis and recycling.
“PF555 is an ultra-stable organic fluorophore unlike any previously reported. It will allow researchers to observe biological phenomena that were once restricted by time limitations,” Professor Sung Ho Ryu remarked.
The molecule can effectively track both individual proteins at the single-molecule level and multiple proteins simultaneously at a bulk level.
With a “longer photobleaching lifetime than conventional organic dyes”, PF555 does not require any anti-photobleaching additives, the scientists remarked. Additionally, one the most advantageous properties of PF555 is that it is not affected by oxygen concentration.
Another significant finding showed that EGFR exists in two distinct states. Kim et al. suggested that when in its active state, EGFR navigates its environment, “potentially to detect external signals or facilitate molecular interactions”.
The findings were published in Nature Methods.
