Optoelectronics Used to Improve Fluorescent Dyes

Michigan State University researchers have found a new way to increase the brightness and tissue penetration of fluorescent dyes using technology traditionally reserved for solar power. The results, published in the current issue of Scientific Reports, showcase dramatic improvements in light-activated fluorescent dyes for disease diagnosis, image-guided surgery, and site-specific tumor treatment.

"We've tested this concept in breast, lung cancer, and skin cancer cell lines and mouse models, and so far it's all looking remarkably promising," said co-senior author Sophia Lunt.

"This work has the potential to transform fluorescent probes for broad societal impact through applications ranging from biomedicine to photocatalysis—the acceleration of chemical reactions with light," added Richard Lunt, co-senior author. "Our solar research inspired this cancer project, and in turn, focusing on cancer cells has advanced our solar cell research; it's been an amazing feedback loop."

Prior to the Lunts' combined effort, fluorescent dyes used for therapeutics and diagnostics, aka "theranostics," had shortcomings, such as low brightness, high toxicity to cells, poor tissue penetration and unwanted side effects. By optoelectronically tuning organic salt nanoparticles used as theranostics, the Lunts were able to control them in a range of cancer studies. Coaxing the nanoparticles into the nontoxic zone resulted in enhanced imaging, while pushing them into the phototoxic—or light-activated—range produced effective on-site tumor treatment.

The key was learning to control the electronics of their photoactive molecules independently from their optical properties and then making the leap to apply this understanding in a new way to a seemingly unrelated field.