Chinese researchers have developed a biosensor that uses thioflavin T to detect strontium ions.


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Strontium-90 is a radioactive product commonly found in nuclear reactor waste. It has a long half-life and is chemically similar to calcium. This radioisotope takes hundreds of years to decay to negligible levels and can accumulate in the food chain and in bones. It can therefore pose a risk to public health. Unfortunately, strontium(II) ions (Sr2+) are not easy to detect because they do not emit characteristic energy rays. A team of Chinese, British and Greek scientists has found a solution. They published their findings in Nature Sustainability in February.

The scientists used the fluorescent dye thioflavin T. This dye activates DNA to form guanine quadruplex structures. When strontium ions come into contact with this structure, they replace the thioflavin and reduce the fluorescence intensity. This allows them to detect strontium ions at very low concentrations; they report a detection limit of 2.11 nM. This should make it possible to monitor the spread of radioactive strontium contamination in the environment around a nuclear reactor or after a nuclear disaster.