Human tears could carry a flood of useful information.
“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 droplets could open a window for scientists to peer into the entire body, he says, and one day even let people quickly test their tears at home.
Like saliva and urine, tears contain tiny sacs stuffed with cellular messages (SN: 9/3/13). If scientists could intercept these microscopic mailbags, they could offer new intel on what’s happening inside the body. But collecting enough of these sacs, called exosomes, is tricky. Unlike fluid from other body parts, just a trickle of liquid leaks from the eyes.
So Liu’s team devised a new way to capture the sacs from tiny volumes of tears. First, the researchers collected tears from study participants. Then, the team added a solution containing the tears to a device with two nanoporous membranes, vibrated the membranes and sucked the solution through. Within minutes, the technique lets small molecules escape, leaving the sacs behind for analysis.
The results gave scientists an eyeful. Different types of dry-eye disease shed their own molecular fingerprints in people’s tears, the team found. What’s more, tears could potentially help doctors monitor how a patient’s diabetes is progressing.
Now, the scientists want to tap tears for evidence of other diseases as well as depression or emotional stress, says study coauthor Luke Lee, a bioengineer at Harvard Medical School. “This is just the beginning,” he says. “Tears express something that we haven’t really explored.”
'Exosomes'
Nonetheless, collecting enough of these sacs, known as "exosomes," is tricky. Opposite fluid from other body parts, only a trickle of liquid is leaking from the eyes.
Therefore, the team of Liu developed a new approach to capture the sacs from small volumes of tears. Initially, the study's authors published in ACS Nano collected tears from study participants.
Then, they added a solution with tears to a device with nanoporous membranes, vibrated the membranes, and sucked the solution through. The approach allows tiny molecules to escape in just a few minutes, leaving the sacks behind for examination.
The results gave researchers an eyeful. Essentially, the researchers discovered that different dry-eye disease types are shedding their molecular fingerprints in people's tears. More so, tears could help medical practitioners monitor how diabetes in patients develops.
The study investigators wanted to tap tears for evidence of other diseases and depression or emotional stress, explained bioengineer Luke Lee, the study co-author from Harvard Medical School. This, he added, "is only the beginning." Tears express something that has not been explored.
Lysozymes Antiseptic Proteins
A protein in the human that fights diseases has been tethered to a small transistor, allowing scientists to discover precisely how it destroys dangerous bacteria, a ScienceDaily report said
The study published in the Science journal could prove crucial to long-term work targeting cancer and other illnesses in their initial stages.
Ever since Alexander Fleming, a Nobel laureate, discovered that human tears have antiseptic proteins, also known as lysozyme, about 100 years ago, researchers have attempted to solve the mystery of how they could relentlessly wipe out quite larger bacteria.
It appears that lysozymes contain jaws latching on and chomping through rows of cell walls like an individual hungrily gobbling an ear of corn, the study findings showed.
Teardrops for Cancer Detection
According to Gregory Weiss, the molecular biologist and chemistry professor who co-led the study with Philip Collins, associate professor, and physics & astronomy professor, such jaws are chewing apart the walls of bacteria trying to enter the eyes and eventually infect them.
The study investigators decoded the behavior of the protein by building one of the tiniest transistors in the world, 25 times tinier than similar circuitry in laptops or smartphones.
Individual lysozymes were glued to the live wire, and their eating activities were observed. Collins explained, that their circuits are microphones a size of a molecule. He added it's simply like a stethoscope that listens to the heart, except that a single protein molecule is being listened to.
It took years for scientists to construct the transistor and connect single-molecule teardrop proteins. Researchers hope the same novel technology can be used to spot cancerous molecules.
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