Exosomes: A Powerful, New Diagnostic Tool
Your cells are more social than you may think. Chances are, they’re “talking” to each other right now.
Cells shoot out nanoparticle spheres, called exosomes, to help influence the behavior of their neighbors. These little balls, enclosed by a membrane that is packed with interesting molecules, can help diagnose cancer and other diseases. They also appear circulating in fluids all over the body. Current methods have not been good at separating exosomes from other similar particles flowing in fluids like blood. However, researchers at Aalborg University in Denmark have created a microarray that specifically targets exosomes. They printed antibodies onto microarray slides that would catch molecules that are expressed on the exosome surface, specifically three proteins called CD9, CD63, and CD81. They first tested the technique on a sample of colon cancer cells. The researchers discovered that in order to detect the exosomes there needs to be at least 25,000 per microarray spot. However, human blood plasma generally contains much fewer cells in the same volume (at the most 1,000 cells per spot). So, they used Arrayit multi-well cassettes to turn each spot into a test tube, and tried the test again, this time with unpurified plasma from seven different healthy individuals. The best signals on the microarray were samples that were five microliters (about 5,000 times thicker than the spot) and contained about 1 million exosomes each. They then tested each individual’s plasma against a suite of antibodies that can detect various molecules that the exosomes are carrying, many of them able to be used as biomarkers for cancer or autoimmune disease. The concentration of the molecules varied by sample from person to person, except for CD9 and CD81, which stayed fairly consistent between all samples. These two proteins demonstrated that they are excellent indicators for exosomes in a fluid. To read more about this advancement, check out the original paper here: http://www.journalofextracellularvesicles.net/index.php/jev/article/view/20920 |
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524 East Weddell Drive, Sunnyvale, CA 94089 USA Phone: 408-744-1331 Fax: 408-744-1711