Killing cancer with lanthanides and air

Imagine killing cancer cells with oxygen compounds. Then tracking the cancer’s metabolism with near ultraviolet light sources. That’s the potential result of the pioneering work by a team at the University of Nevada-Reno.

Ana de Bettencourt-Dias, Ph.D., leads the group in the research. It uses fluorescence spectroscopy to determine the properties of the light-emitting compounds, which generate reactive oxygen species.

Reactive oxygen species occur in nature, including within our bodies. These can be good or bad. Some are capable of killing cells, according to de Bettencourt-Dias.

The compounds also work with other substances, called lanthanides. These are a group of 15 metal elements that have unique features. One is that they fluoresce when exposed to specific light sources.

“Our most recent work combines the light emission of the lanthanides with the generation of these reactive species,” she said. “It allows us to do cell fluorescence imaging, and at the same time to generate reactive oxygen species, so we can kill the cancer cell with these reactive oxygen species. We are hoping we have a way to control part of the process to target the cancer cells.”

The research is a long way from practical applications.

“We are doing the basic discovery at this point,” she said.

Lanthanide complexes are of increasing importance in cancer diagnoses and therapies, because of the versatile chemical, light-emitting and magnetic properties of a lanthanide ion, according to research published by the National Institutes of Health.

“They are amazing metals,” de Bettencourt-Dias said. “They have lots of interesting properties, most notably magnetism and light-emission.”

Both industry and medicine use lanthanides. Permanent magnets transform wind into energy at wind farms. The magnetism properties are important in contrast agents in magnetic resonance imaging. Catalytic converters, antilock brakes, and DVDs and CDs use lanthanides. These metals are also used in night vision goggles, rangefinders and signal amplification for fiber optics communications.

The luminescence of lanthanide ions has applications from displays to bio-imaging and sensing. Lanthanide-based compounds are also used as anti-counterfeiting agents. The metal compounds are embedded in European currency; if you hold an ultraviolet light up to it, it will luminesce.

It’s possible to use lanthanide compounds to incubate with cells. This way, scientists can see how the compounds’ light to image within the cells. That gives them information about the cells themselves and some of the processes going on, related to the cells’ metabolism.

The de Bettencourt-Dias’ research group studies the light emission of the molecules she makes. She uses HORIBA Instrument’s FluoroLog®-3, a steady state and lifetime modular spectrofluorometer, to measure the efficiency of the light emission of the compounds. De Bettencourt-Dias is in the process of upgrading the FluoroLog-3 to incorporate more intense light sources for her research. She uses the spectrometer to measure the most efficient compounds for light emission. With it, her team can compare different compounds to each other.

The majority of what her group does is try to determine what makes for a good ligand (a sensitizer for exciting lanthanide atoms). They make new ligands, test how well they work, and try and determine why they work better or worse than expected.

Her group is interested in developing new ligands for highly emissive lanthanide ion complexes. The team synthesizes the ligands and the metal complexes, and then characterizes these with different spectroscopic methods, such as single crystal X-ray diffraction, and absorption, excitation and emission spectroscopy.

De Bettencourt-Dias is well traveled. She earned her master’s in technological chemistry from the University of Lisbon and her Ph.D. in inorganic chemistry from the University of Cologne. She also served as a post-doctoral researcher at the University of California-Davis before accepting a professor position at Syracuse University. De Bettencourt-Dias has been at the University of Nevada-Reno for over 11 years.

Reactive oxygen species have already been used in cancer treatment, like in Photodynamic Therapy, which is primarily used to treat skin cancer, she said.

De Bettencourt-Dias is in the forefront of her field.

“We are proposing the ability to treat cancer with the ability to do imaging at the same time so you can more accurately target cancer cells,” she said. “We are using luminescence and targeted design of the molecules using the FluoroLog-3, doing extensive research on the properties of these compounds for their luminescence and ability to generate reactive oxygen species.”

Students do the research that de Bettencourt-Dias oversees.

“They get the opportunity to learn techniques that are not usually learned in undergraduate chemistry training,” she said.

Follow Us