RAPID CITY – While using cold plasma to kill cancer cells isn’t an entirely novel concept, a team of researchers and students at South Dakota School of Mines & Technology are exploring new ways to regulate cold plasma technology to target and kill cancer cells while leaving healthy cells alive.

If successful, the technique would prove to be a drug-free, minimally invasive cancer treatment that would affect the lives of millions of patients around the world.   

Plasma is ionized gas – an energetic state of matter where some of the electrons in the outer atomic orbitals have become separated from the atom. In other words, it’s a collection of ions and electrons no longer bound to each other. Cold plasma is a partially ionized gas where particles possess much higher energy.

SD Mines assistant professors Prasoon Diwakar, Ph.D., of the mechanical engineering department, and Timothy Brenza, Ph.D., of the chemical and biological engineering department, are overseeing the research with undergraduate mechanical engineering students Kristen Haller and Nicole Miller. 

Chemical and biological engineering PhD student Jordan Hoops and applied biological sciences undergraduate student Taylor Bright are also contributing to the work. Bright will be continuing the research in this area as an accelerated master’s student in biomedical engineering.

Diwakar began researching cold plasma cancer treatments as a postdoctoral research associate at Purdue University in West Lafayette, Indiana. While at Purdue, Diwakar worked with Ahmed Hassanein, a professor of nuclear engineering, to develop PLASMAT, or Plasma Technologies, for a Healthier Tomorrow. 

The PLASMAT technique combines cold atmospheric plasma (CAP) with electroporation and/or photoporation in order to kill cancer cells without destroying healthy cells.

When he arrived at SD Mines in 2018, Diwakar began collaborating with Brenza, whose lab works with cancer cells in drug delivery research, including lung cancer.

Together, the researchers turned their eye toward using cold plasma to treat lung cancers, but with a specific goal of vastly improving the plasma’s capability of targeting potential of cancer cells only.  

Diwakar explains that cold, atmospheric plasma is not cold, but room temperature. Diwakar demonstrates by holding his finger in a delicate, blue stream of laser light. It causes no damage to his finger. However, a specific level applied to cancer cells will destroy them.

In order to kill cancer cells, however, the pores of the cells must be opened to allow the cold plasma to be “shot” into the interior of the cell. Electroporation opens the cell pores. 

Haller demonstrates this by placing the cells, which have been suspended in a conductive solution, into an electroporation system. An electrical pulse lasting just milliseconds is discharged through the cells, disturbing the outer membrane and creating temporary pores. Once the pores are opened, Haller shoots cold plasma into the interior of the cell where the cancer cells are located. The cold plasma introduces reactive oxygen and nitrogen into the cancerous cells, which leads to apoptosis or death of the cancer cells.

Diwakar says researchers have used cold plasma to “push cancer cells over the limit so they die.” But this new research is focusing on finding the “right limit” – the level of cold plasma dosage needed to only kill the strain of cancer cells without damaging any healthy cells nearby. 

By identifying the limit, doctors will be able to apply proper dosage of cold plasma based on the type of cancer, the strain of cancer cells and other specifics – all while leaving healthy cells thriving, he says.

Eventually, this cold plasma process could be introduced into cancerous tissues and/or tumors in a person’s body to kill the cancer cells. 

And, unlike chemotherapy or even radiation, it would so precisely target the cancer cells that patients would not suffer the side effects that they do now with traditional treatments, including loss of hair, burned skin, nausea, etc.

Electroporation and cold plasma treatment would be most feasible for cancers that are easily reached in the body, such as skin cancer or cancers that cause localized tumors that can be accessed. But once this research is successful, the next step will be application of the treatment to less accessible cancers, Diwakar says. 

Obviously, cancer inside the body would have to be exposed for electroporation to occur followed by cold plasma application. 

“If it’s proven it can work, we’ll have to change how it’s applied. The cancer-affected area must be exposed. But we have some ideas,” Diwakar says, including accessing the cancer with laparoscopy. 

The team has shown preliminary results that the combination of cold plasma and electroporation is effective in killing lung cancer cells. 

Haller and Miller were chosen from undergraduates around the country to present the results at the SCIX 2019 The Great Scientific Exchange Conference in Palm Springs in October 2019. The next step is to study the exact mechanism which leads to cell death.