NOV 01, 2019 7:00 AM PDT

Cancer Therapy Agents Inspired by Solar Technology

WRITTEN BY: Daniel Duan

In a recent study, a group of biomedical researchers at Michigan State University developed a new platform for tweaking light-activated dyes that can enable diagnostic imaging, image-guided surgery, and site-specific photodynamic treatment. Their idea borrowed a mechanism from a seemingly unrelated field — solar energy.

Photodynamic therapy (PDT) relies on photosensitizing agents and light of specific wavelengths to produce reactive oxygen molecule which triggers cell death.  It has a proven track record in treating acne. Scientists have achieved some success in using PDT in topical cancers. Still, due to the limit of light penetration, its effectiveness in killing tumor tissues that are deeply embedded in the human body need improvement.

In the current study, two of the senior researchers Sophia and Richard Lunt, an assistant professor in Biochemistry and Molecular Biology and a professor in Chemical Engineering and Materials Science, combined their knowledge and expertise in two separate fields and delivered a home run — a brand new method of cancer diagnosis and treatment.

Richard Lunt brought his experience working with photovoltaics, specifically the cyanine-based organic salts, into this research. These photosensitive compounds are known for their photovoltaic effect, which is the generation of voltage within the material upon exposure to light. The same phenomenon underpins the functional mechanism of solar power panels.

The Photoelectric Effect (OpenMind)

In a previous study, Richard Lunt's team demonstrated that the coupling of a handful of novel anions with a near-infrared (NIR)-sensitive cation manipulation of the electronics of photoactive molecules independently from their optical properties. In the current study, the research group used a similar principle: they explored the pairing of anions and cations, in order to find ways to control cytotoxicity and phototoxicity of the fluorescent compounds independently. 

To function as an effective drug for cancer therapy, a PDT fluorescent dye needs to be phototoxic but not cytotoxic, so that it will only deliver a lethal blow to cancerous tissues when distributed to a proper location and given light exposure. But finding the sweet spot between the two properties requires a delicate balancing act.

Cytotoxic Anions
Phototoxic Anions
Nontoxic Anions
iodide (I−), hexafluoroantimonate (SbF6−), hexafluorophosphate (PF6−), o-carborane (CB−) tetrakis(4-fluorophenyl)borate (FPhB−), cobalticarborane (CoCB−) tetrakis(pentafluorophenyl)borate (TPFB−), tetrakis[3,5-bis(trifluoro methyl)phenyl]borate (TFM−), tris(tetrachloro-1,2-benzene diolato) phosphate(V) (TRIS−)

The pairing of counterions that showed an arrange of different toxicity profile

The Michigan State group achieved this by pairing the NIR-absorbing cyanide cations with various counterions. To assess their cytotoxic properties, they treated human lung carcinoma and metastatic human melanoma cell lines with these dyes. Counterion pairings with small hard anions showed high cytotoxicity at low concentrations, whereas the pairings with bulkier, halogenated anions can remain nontoxic at much higher concentrations. 

Among all test candidates, they also found one that actually hit the sweet spot: an intermediate group of anion pairings exhibited high phototoxicity but negligible cytotoxicity.

The researchers hope that their way of exploring cytotoxicity and phototoxicity of fluorescent organic salts would allow for the development of more effective PDT agents for cancer treatment.

This research is published in the journal Scientific Reports.

Source: Medical Express

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
MAY 05, 2020
Clinical & Molecular DX
A High Resolution Glimpse Inside the Brain
MAY 05, 2020
A High Resolution Glimpse Inside the Brain
Imagine a future where we could “see” inside the human brain at stunning high resolution, detecting the earl ...
JUN 24, 2020
Chemistry & Physics
Acoustic levitator allows for touchless chemical experiments
JUN 24, 2020
Acoustic levitator allows for touchless chemical experiments
Have you ever heard of an acoustic levitator? Acoustic levitation uses acoustic radiation pressure from high-intensity s ...
JUN 16, 2020
Technology
How True Is Teleportation?
JUN 16, 2020
How True Is Teleportation?
Teleporting worlds is something only seen through the lens of science fiction. For example, many Star Trek fans can reca ...
JUL 12, 2020
Chemistry & Physics
Scientists mimic nacre's strength and resiliency
JUL 12, 2020
Scientists mimic nacre's strength and resiliency
Did you know that mother of pearl - also called nacre - is not only stunningly beautiful but also one of the strongest m ...
JUL 22, 2020
Infographics
The Science of Sourdough
JUL 22, 2020
The Science of Sourdough
During the coronavirus stay-at-home order, many people have taken up the art of making sourdough bread and have learned ...
JUL 26, 2020
Chemistry & Physics
This hydrogel memorizes and forgets, just like our brains
JUL 26, 2020
This hydrogel memorizes and forgets, just like our brains
A hydrogel developed by researchers at Hokkaido University is the first material to mimic the human brain’s capabi ...
Loading Comments...