ITP Multiplex Technology Used to Isolate and Identify Exosomes

Washington State University researchers have developed a new paper-based isotachophoresis (ITP) technology for rapid isolation and identification of exosomes from both malignant and healthy cells as well as multiplex detection of selected exosomal protein biomarkers of the target exosomes. They report that their technology is more than 30 times more sensitive than current lab-based tests in finding early stage cancer biomarkers in blood.

In addition, according to Wenji Dong, senior author of the paper published in Biosensors and Bioelectronics, and first author Shuang Guo, the team was able to detect miniscule levels of the cancer markers in exosomes in as little as 10 minutes.

While traditional lab tests to detect tumor biomarkers in blood have been developed, they often can't find early-stage cancer because the cancer markers are at levels too low to detect. Instead, people most often find out they have cancer through invasive biopsies once tumors are established.

In recent years, researchers have discovered that one of the ways cancer cells spread and communicate with other parts of the body is by way of tiny exosome vesicles in blood or other fluids. Ranging in size from 40 to 120 nanometers, or about 1000 times smaller in width than a strand of hair, the exosomes are thought to shuttle molecules from parent cancer cells through the body, entering and then re-programming friendly cells to become cancerous. Cancer cells also secrete more exosome bubbles than regular cells.

"Exosomes provide a unique opportunity as a cancer marker," Dong said. However, finding the cancer-filled exosomes in blood testing is challenging. They look the same as normal cell exosomes and other extracellular bubbles, and they are at very low levels in the blood in early cancer.

Using their unique approach, the WSU team was able to concentrate and then separate the cancer-cell exosomes from those from normal cells by way of immune-binding. They were also able to separate out and analyze cancer protein markers within the exosomes.