Traditionally, testing a water sample for mercury has involved an expensive, lab process. Aydogan Ozcan, a professor at UCLA, says standard techniques such as atomic absorption spectroscopy and inductively coupled plasma-mass spectrometry aren’t exactly easy to do in the field in, say, Uganda.
Ozcan’s lightweight alternative is based around a smartphone. It uses a simple 3-D printed attachment. And, it comes in at a fraction of the old cost. It could make mercury testing much easier and more widespread. “The cost per test could be as low as five cents,” he says. “The attachments, which weigh less than 40 grams, cost about $37 each to produce, and could be lower cost if they are made in large quantities.”
That attachment passes two frequencies of light through a test tube sample. The liquid is mixed with an assay of gold nano-particles and short DNA fragments that changes color in the presence of mercury. The phone’s camera detects concentration levels by assessing how light transfers through the sample.
The entire test takes 20 minutes and can detect at levels small enough to be useful to groups like the U.S. Environmental Protection Agency and the World Health Organization. The results can also be mapped using an accompanying app.
It’s only the latest lab-on-a-phone test Ozcan’s lab has developed. He has several patents for tests related to infectious disease monitoring, and has commercialized a platform called Holomic. See him talk about that below:
As for the mercury test, Ozcan hopes to have that into the market within two years. “This technology could be especially useful for developing countries, where rapid industrialization without proper infrastructure or legal measures has resulted in severe heavy metal contamination,” he says.