nuclear waste

Scientists Use Molecular “Claw” to Remove Uranium From Irradiated Mice

Researchers from China’s Soochow University have developed a new molecular “claw” that hooks onto toxic uranium isotopes, making them easier for the kidneys to excrete. If proven functional in humans, it would represent the first effective way for quickly removing the heavy metal from a person’s body. The method could prove vital in areas with contaminated groundwater and for the unfortunate ones who drink it.

Uranium is a very important but dangerous element. As a nuclear fuel, it is used to generate about 10% of the world’s electricity in nuclear power plants. Naturally occurring uranium (U) consists of three isotopes: 99% U-238, 1% U-235 and U-234 in traces. Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. U-235 is the only naturally occurring fissionable fuel (a fuel that can sustain a chain reaction). In a breeder reactor, U-238 becomes plutonium-239, a synthetic and also fissionable element. Of the 22 recognized isotopes, only a few are toxicologically significant.

Depleted (less radioactive) uranium is a dense metal that can be used as ballast for ships, counterweights for aircraft or in ammunition and armour. People should avoid ingesting or being exposed to this heavy metal at any cost. If you receive a small dose, the body will ditch two-thirds of it fairly quickly. Swallowing several grams of the element is necessary for severe poisoning.

However small the risks are, the consequences can be dire. Any remaining non-excreted uranium accumulates in the body. Nuclear researchers, workers in uranium mines and mills are all in risk of respiratory and kidney disease. Drinking contaminated groundwater also puts consumers at risk of kidney diseaseand uranium build up in bones.

Although there are a few ways to mop some of it up from your tissues, most methods are inefficient or toxic themselves. Removing heavy metals (mercury or lead) usually requires a therapy called chelation. There, “sticky” molecules grab the plus-sized metal atoms and make it easier for kidneys to remove from the body. Two chelating agents that can be used for removal of uranium are based on the chemical diethylenetriamine pentaacetate (DTPA) but do so poorly.

Now scientists from China’s Soochow University have designed a new technique that effectively removes uranium atoms from animal tissue. The novel “metal-hugging” molecule they developed packs a good “grip” on uranium atoms and is already showing promise in tests with mice. This research was published in Nature.

The chelating agent called hydroxypyridinone (5LIO-1-Cm-3,2-HOPO) is the molecule that showed promise. It proved to be less toxic than current options and did a better job when evaluated in mice. The molecule removed 80% of the residual uranium from the kidneys of irradiated mice. When injected straight into their abdomens, it “pulled” between a third and half the uranium from the animals’ bones. According to Science Alert, other available options for uranium removal only managed to pull about 20% from the mice’s kidneys and 10% from their bones. That indicates a big confirmation that could have huge significance for affected people.

In 2008, widespread uranium poisoning in India caused panic. A spike in congenital disabilities and various abnormalities and cancers among children concerned the public. High levels of the uranium were found in hair samples taken from children in the state of Punjab. Hundreds of children suffered from poisoning, and the amount of heavy metal in one child’s body was 60 times the maximum safe limit. The contamination could have come from nearby coal-burning power stations or a more natural source. Unfortunately, this is not the only example in India. In 2018 researchers have found that the nation’s groundwater still contained unsafe levels of uranium.

There is no easy way of clearing the system of all uranium from a potentially toxic dose. Researchers hope to the positive outcome of clinical trials. After all, the new molecular “claw” could very well make a difference. Cleaning up water sources could take longer than the development of effective therapy.  

Learn more about radiation poisoning in the video below:

By Andreja Gregoric, MSc

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