CLEMSON — Research aimed at creating a new biosensor that would help military investigators search for signs of nuclear activities, including weapons development, is moving forward under the leadership of a former naval officer who now is a Clemson University faculty member.

Nicole Martinez and her team are beginning to lay the groundwork for a biosensor that could help determine whether the radiation is natural or manmade and peaceful or weapons grade. It could help investigators search for labs amid concerns a nation or group could illicitly develop weapons of mass destruction.

Nicole Martinez demonstrates her research in a lab at Clemson University.

Nicole Martinez demonstrates her research in a lab at Clemson University.

“The unique aspect of the biosensor we envision is that it would give an indication of radiation exposure even after the radiation source is removed or relocated,” Martinez said. “Moreover, the proposed biosensor may distinguish between types of radiation, which would provide insight into its origin.”

The biosensor would be an improvement on current radiation-detection systems that are easily identified, must be placed close to the radiation source and report on radiation emitted only at the time the detection system is present.

Martinez, an assistant professor in the environmental engineering and Earth sciences department, is the principal investigator on the $866,884 project. It lasts three years and could be eligible for a two-year extension, boosting the total to about $1.5 million.

The team had its kickoff meeting this week.

The project is funded by the U.S. Defense Threat Reduction Agency. Mark Blenner, the Dean’s Assistant Professor of Chemical & Biomolecular Engineering  is the co-principal investigator.

Exactly how the biosensor would be used and what it would look like has not been determined and would ultimately be up to the Department of Defense.

But if the biosensor functions as hoped, it could be the first based on how bacteria and yeast change DNA to RNA, a process called transcription.

Researchers will study how tritium, iron-55, plutonium-239 and neutron irradiation affect transcription in three types of bacteria and two kinds of yeast.

The effect of high doses of ionizing radiation on biological systems is well known, but much less is understood about the effect of low doses. Researchers expect to find distinctive responses at the sub-cellular level based on different types of radiation.

“The value of what we’re doing supports application but isn’t the application itself,” Martinez said. “Our research questions are along the lines of: ‘Do bacteria exhibit a unique response to radiation exposure compared to other environmental signals and stressors?  If so, does that uniqueness extend to the type of radiation to which it was exposed? If so, can we identify that unique signature or pattern of gene regulation? Can we utilize this signature to our advantage and engineer a related biosensor of radiation type?’”

The research will also involve measuring the effects of low-level radiation.

“We are looking at patterns of gene regulation that occur in response to exposure to low levels of radiation,” Martinez said.

The project came together after Blenner saw the need for alternative approaches to monitoring nuclear activities and had the idea to use microorganisms.

“He eventually linked up with me for the radiation expertise, and together we worked out what we thought the best experimental design would be,” Martinez said. “He chose the microorganisms, and I chose the isotopes. I planned exposures/dosimetry, and he planned the genomic/transcriptomic analysis.

“We decided on me being the principal investigator as we expect a lot of the work will be physically done at my lab and I have the more open schedule to dedicate to the management of the project. Intellectually, Dr. Blenner contributes as much or more than I do.”

Blenner said he looks forward to working with Martinez and that the research presents some promising opportunities to advance knowledge in an area important to defense.

“Microorganisms are ubiquitous in nature and their properties are often sensitive to their environment,” Blenner said. “It was a logical extension to suppose we could use them to detect and discriminate different radiation sources.

“This idea stems from my group’s work on using microbes as chemical factories and sensors in resource-poor settings. However, without Dr. Martinez and her expertise in radioecology, this project would not be possible.

“This study is our first step towards engineering systems that discriminate source and dose of radiation that could be autonomously deployed to report on nuclear weapons proliferation.”

Before going to graduate school, Martinez served as an instructor at the Nuclear Power School and later as a hospital-based radiation health officer. She went on to receive a master’s degree and doctorate, both in radiological health sciences from Colorado State University.

She joined Clemson in August 2014.

David Freedman, chair of environmental engineering and Earth sciences, congratulated Martinez on the grant.

“Dr. Martinez and her team are helping advance the science necessary to detecting weapons of mass destruction,” he said. “The award is well-deserved.”

Martinez said she finds radiation fascinating.

“Radioactivity occurs naturally and can also be induced. It can both cause and cure cancer,” she said. “It aids in diagnostic medicine. It gives insight into environmental processes. It can provide a source of clean energy. Yet for all this, it still has destructive potential.

“Radiation has so much to offer but needs educated respect and stewardship,” she said. “I’m motivated to do what I can to ensure the safe and effective use of radiation and radioactivity.”


The project or effort depicted was or is sponsored by the Department of the Defense, Defense Threat Reduction Agency. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred.