Human tears can carry a stream of useful information.
With just a few drops, a new technique can spot eye disease and even glimpse signs of diabetesscientists report on July 20 in ACS Nano.
“We wanted to demonstrate the potential of using tears to detect disease,” says Fei Liu, a biomedical engineer at Wenzhou Medical University in China. It’s possible the drops could open a window for scientists to look into the whole body, he says, and one day even allow people to quickly test their tears at home.
Like saliva and urinetears contain tiny sacs filled with cellular messages (ЗН: 03.09.13). If scientists could intercept these microscopic mail bags, they could offer new information about what goes on inside the body. But collecting enough of these sacs, called exosomes, is difficult. Unlike fluid from other parts of the body, only a trickle of fluid flows from the eyes.
So Liu’s team came up with a new way to capture sacs from tiny volumes of tears. First, the researchers collected the tears of the study participants. The team then added a solution containing tears to a device with two nanoporous membranes, vibrated the membranes, and sucked up the solution. Within minutes, this method allows the small molecules to escape, leaving behind bags for analysis.
The results impressed the scientists. The team found that different types of dry eye leave their own molecular imprints in people’s tears. What’s more, tears can potentially help doctors monitor a patient’s diabetes.
Scientists now want to find evidence of other diseases in tears, as well as depression or emotional stress, says study co-author Luke Lee, a bioengineer at Harvard Medical School. “This is just the beginning,” he says. “Tears express something we haven’t explored yet.”