The molecular structure of molecule 2F and its phototheranostic application.
Cancer is one of the leading causes of death worldwide. Due to the complex nature of tumors, effective treatment remains a significant challenge. This has driven scientists across the globe to develop novel and efficient strategies for cancer diagnosis and therapy.
Surgery, chemotherapy, and radiotherapy are three of the most common approaches for treating cancer. However, these methods often cause severe side effects and harm healthy tissues. Given that tumor cells are, at their core, still biological cells, researchers have begun exploring what kinds of external stimuli might selectively eliminate them.
Heat is one of the oldest stimuli known to eliminate biological cells. Historically, it has been applied in clinical settings to treat tumors, and its mechanisms have been well studied. Under normal conditions, heating tumor cells to 39–41 °C can slow or halt their proliferation, while temperatures around 42–43 °C may induce shrinkage or apoptosis. The main challenge now lies in precisely controlling heat generation within the target tissue—releasing enough heat to effectively kill tumor cells while avoiding damage to surrounding healthy cells.
To achieve this goal, researchers from NTU and CityUHK found a clever way to repurpose small organic molecules once used in organic solar cells — molecules that can absorb sunlight and convert solar energy into electricity. They modified their structures to convert the energy into heat instead and synthesized novel photosensitizers named CN and 2F.
These two new molecules, CN and 2F, were built with a specific goal: to work with near-infrared light, which travels deeper into tissue than visible light. CN does a decent job in the visible range, but 2F goes further—it was fine-tuned to catch light at around 808 nm. That longer wavelength helps it reach tumors hiding beneath the surface. What makes 2F stand out isn’t just how far the light goes—it’s what happens after. Once the light hits, 2F efficiently turns it into heat, which can help destroy cancer cells without affecting nearby healthy tissue.
One of the strengths of CN and 2F lies in how straightforward they make—at least compared to many other near-infrared dyes. Instead of using rigid, fused-ring structures that often require complex and time-consuming chemistry, these molecules are built from simpler building blocks and assembled through just two main steps. While some of the starting materials still need to be prepared or sourced, the overall process is relatively short and efficient.
Moreover, both molecules can be synthesized in good yield, meaningless waste and more material for testing or future production. It’s a design that balances performance with practicality—something that’s often hard to achieve in molecular engineering.
To test their real-world potential, the researchers evaluated 2F nanoparticles in both cell cultures and animal models. On their own, the particles showed minimal toxicity—but once exposed to near-infrared light, they rapidly heated up and selectively eliminated cancer cells, sparing the surrounding healthy tissue. In mice, a single dose of 2F followed by NIR irradiation was enough to halt tumor growth and, in some cases, shrink tumors significantly.
Just as importantly, the nanoparticles could be tracked in real-time using photoacoustic (PA) imaging. Thanks to their strong NIR absorption, 2F produced a clear PA signal at the tumor site, peaking about six hours after injection. This ability to both locate and destroy tumors with spatial precision makes 2F a powerful candidate for light-driven cancer therapy.
“We believe that the interdisciplinary collaboration, particularly between molecular design and biomedical applications, is essential to the success of this work.” says Prof. Ken-Tsung Wong.
“We hope this work will encourage more partnerships not only in Taiwan but also across Asia and beyond, with biomedical teams interested in applying novel molecular systems to clinical research.”
Reported by Allen Chu-Hsiang Hsu
Prof. Ken-Tsung Wong’s email address: [email protected]
