“Molecular jackhammers” – molecules that vibrate trillions of times per second when stimulated by infrared light – can destroy cancer cells, which could lead to “revolutionary” treatment of some cancers, researchers say.
The researchers, who reported their findings in the journal, Nature Chemistry, say the atoms of a common dye molecule used for medical imaging can vibrate in unison at 40 trillion oscillations per second when stimulated by near-infrared light – electromagnetic radiation wavelengths invisible to the eye that are safe and penetrate deep in the body.
The process, in turn, transforms the molecules into the powerful molecular jackhammers that tear apart the membranes of cancerous cells, leading to the cancer cells being destroyed, according to the study. The molecular jackhammers are then eliminated from the body through urine.
“I view this as potentially revolutionary in treatment of cancer because this is a totally new method that works through mechanical forces that destroy the cancer cell,” said Dr. Ciceron Ayala-Orozco, a Rice University research scientist and the study’s lead author. “We can destroy the cancer cells through mechanical force very efficiently, which is something that has not been done before.”
Experiments yielded an extraordinary 99% success rate in destroying cancer cells in tests targeting human melanoma cells in the lab, and half of mice with melanoma tumors became cancer-free after treatment.
Ayala-Orozco says he expects further research to show much higher success rates among mice, but for now, his team is moving on to studying how well the molecular jackhammers work against other cancers. They include pancreatic cancer, which researchers hope to treat by triggering molecular jackhammers through infrared light filtered through the GI tract using optical fibers.
Ayala-Orozco says he’s also hopeful the treatment could prove effective in targeting colorectal cancer and colon cancers, among others.
The electrons inside the molecular jackhammer molecules form what are known as plasmons, collectively vibrating entities that drive movement across the entire molecule.
The molecules, Ayala-Orozco explains, attach themselves to the fatty outer lining of cancer cells. But through targeting the beams of near-infrared light, the rapid vibrations can be localized so they attack only the tumor without damaging other cells or tissue, according to the study.
The near-infrared light also can penetrate far deeper into the body than visible light, enabling it to access organs or bones without damaging tissue and potentially eliminating the need for invasive surgery, the researchers say. Near-infrared light can penetrate as deep as 10 centimeters (4 inches) into the human body as opposed to only half a centimeter (0.2 inches) for visible light, the study said.
Ayala-Orozco, who began studying plasmons as a doctoral student, says the key to the latest research came when his team discovered that the near-infrared light could make the cancer-killing molecules move in unison so much more rapidly than in past research. And the molecular jackhammers can wipe out cancer cells in just minutes, much faster than radiation, chemotherapy or photodynamic therapy, which converts light into heat energy to kill the cancer cells.
The molecular jackhammers also could be used to drill through the outer membranes of infectious bacteria and treatment-resistant fungi to cure illnesses other than cancer, researchers say.
“These molecules are simple dyes that people have been using for a long time,” Ayala-Orozco said. “But even though they were being used for imaging, people did not know how to activate these as plasmons. I basically connected the dots.”
“We’ve discovered another explanation for how these molecules can work. This is the first time a molecular plasmon is utilized in this way to excite the whole molecule and to actually produce mechanical action used to achieve a particular goal ⎯ in this case, tearing apart cancer cells’ membrane. This study is about a different way to treat cancer using mechanical forces at the molecular scale.”
Dr. Sunil Krishnan, a professor of radiation oncology and director of radiation oncology research at the University of Texas’ McGovern Medical School, called the study’s results “tantalizing.”
Krishnan, who was not involved in the study, noted that the research found that the molecular jackhammers, activated by near-infrared light, could reach deeper into tissues and organs than treatments that rely on visible light.
But he cautioned that extremely careful targeting of infrared light would be essential to avoid damaging or killing non-cancerous cells.
Ayala-Orozco says the team has no timetable for when the treatment might be tested on humans.
