Material from shellfish delivers a boost to bioassays and medical tests

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July 17, 2017







Scientists at the University of Washington have discovered a simple way to raise the accuracy of diagnostic tests for medicine and common assays for laboratory research. By adding polydopamine — a material that was first isolated from shellfish — to these tests at a key step, the team could increase the sensitivity of these common bioassays by as many as 100 to 1,000 times.
More sensitive tests would allow scientists to identify pathogens, diseases and specific cellular proteins even when these “biomarkers” are present at levels far below the detection threshold of today’s standard tests. Initial results show polydopamine boosted the accuracy and resolution of these tests for biomarkers of HIV, Zika virus and proteins on cancerous tumors.
“Common bioassays are the real workhorses of laboratory experiments and medical tests,” said Xiaohu Gao, a UW professor of bioengineering. “By boosting the sensitivity of these tests, we can enable more accurate medical diagnoses earlier in a disease or condition, and enable more certainty and less waste in the research process.”
Gao led the team that developed this simple modification for many common medical and laboratory assays. They recently published their approach — known as enzyme-accelerated signal enhancement, or EASE — in Nature Biomedical Engineering.

An artistic rendering of a virus particle (light blue, foreground) bound by brightly-colored reporter molecules in a common laboratory assay.Junwei Li/Xiaohu Gao

EASE centers on the simple addition of two biochemical components, dopamine and horseradish peroxidase, or HRP, at a key step. HRP is a common protein enzyme used to speed up the rate of reactions in biomedical research. Gao and his team discovered that HRP can connect dopamine molecules together to form the polymer chain polydopamine. Polydopamine, in turn, accumulates on the surfaces of reaction vessels, such as small Petri dishes. Once the polydopamine is present, scientists can continue the traditional steps of ...

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