'Wearable 'microbrewery' can protect humans from radiation damage'

Scientists have engineered yeast "microbreweries" that can help hospital lab workers better track their daily radiation exposure, enabling a faster assessment of tissue damage that could lead to cancer.

The researchers at Purdue University in the US used disposable badges made of freezer paper, aluminum and tape to grow yeast, rather than building portable cellars or ovens.

Simply adding a drop of water activates the yeast to show radiation exposure as read by an electronic device, according to the research published in the journal Advanced Biosystems.

On a commercial level, the readout device could one day be a tablet or phone, researchers said.

The badge could also be adapted in the future for nuclear power plant workers and victims of nuclear disasters, they said.

"You would use the badge when you are in the lab and recycle it after you have checked your exposure by plugging it into a device," said Manuel Ochoa, a postdoctoral researcher at Purdue.

Radiology workers are regularly exposed to low doses of radiation when they obtain patient imagery, such as X-rays.

While protective gear largely keeps workers within a safe range of radiation exposure, absorbing a little bit is still inevitable.

Radiation doses creeping above regulated guidelines pose risk for developing conditions such as cancer, cataracts, skin irritation or thyroid disease.

"Currently, radiology workers are required to wear badges, called dosimeters, on various parts of their bodies for monitoring their radiation exposure," said Babak Ziaie, a professor at Purdue.

"They wear the badges for a month or two, and then they send them to the company that made them.

"But it takes weeks for the company to read the data and send a report back to the hospital. Ours give an instant reading at much lower cost," said Ziaie.

The success of the badge lies in the quick and measurable response of yeast to radiation: The higher the radiation dose, the higher the percentage of yeast cells that die.

Wetting the badge activates the cells that are still alive to eat glucose and release carbon dioxide - the same fermentation process responsible for brewing beer and making bread rise.

When carbon dioxide bubbles at the surface, ions also form.

The concentration of these ions increases the electrical conductivity of yeast, which can be measured by hooking up the badge to a readout system.