SAN FRANCISCO, July 23 (Xinhua) -- Researchers at the University of Washington (UW) have discovered a simple way, by adding polydopamine to diagnostic tests for medicine and common assays for laboratory research at a key step, to raise the accuracy of these tests.
Polydopamine, a material first isolated from shellfish, could help increase the sensitivity of the tests by as many as 100 to 1,000 times.
"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."
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.
Gao led the team that developed this modification for common medical and laboratory assays and recently published their approach, known as enzyme-accelerated signal enhancement, or EASE, in Nature Biomedical Engineering.
EASE centers on the 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's 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. Once the polydopamine is present, researchers can continue the traditional steps of their protocols, but now with a substantially increased test sensitivity.
"Scientists have been trying to improve the accuracy of these common tests for decades, but solutions often involve entirely new protocols or costly pieces of equipment," explained Gao. "Understandably, researchers can be reluctant to invest in unfamiliar protocols or expensive new equipment, but EASE is a simple addition to tried-and-true assays. It's like a software upgrade, instead of changing your operating system."
These assays include some of the most common medical and laboratory tests. Some of these assays have been used for decades to help hospitals and doctors detect signatures of a disease, ailment or other conditions by looking at a patient's blood, other body fluids or cells. Depending on the test, these telltale signs could be pieces of a bacteria or virus, a chemical, antibodies made by white blood cells, a hormone or even pieces of deoxyribonucleic acid (DNA).
If these compounds are present at extremely low levels, diagnostic tests can miss them and return inaccurate medical information. By increasing sensitivity, EASE reduces uncertainty and increases the amount of information these tests can provide. For example, the team used EASE to detect the presence of Zika virus in the placental tissues of primates. EASE made the assay so sensitive that the team was able to see which types of cells within the placenta were infected with Zika.
Gao was quoted as saying in a news release from UW that he hopes this simple modification will mean that scientists and medical professionals can easily incorporate EASE into their common practices and procedures.
