Jun 5 2020
Scientists at Washington State University (WSU) have designed a technology that is 30 times more sensitive compared to the existing lab-based tests in determining early-stage cancer biomarkers in blood.
Image of the paper-based isotachophoresis (ITP) device that isolates, enriches, and detects exosomes from a prostate cancer cell line. Image Credit: Washington State University.
The technology involves using an electric field to concentrate and isolate cancer biomarkers onto a paper strip. In the future, it could turn out to be a type of liquid biopsy and might result in earlier detection and quicker treatments for cancer, a disease that causes over 9.6 million deaths per year globally.
Under the guidance of Wenji Dong, an associate professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, and graduate student Shuang Guo, the team could identify minuscule levels of the cancer markers in small extracellular bubbles known as exosomes in just 10 minutes.
The study was reported in the Biosensors and Bioelectronics journal and is considered to be a “significant step” in the early detection of cancer and to develop rapid tests.
For a long time, scientists have been looking for techniques for early cancer detection to save more lives. Although laboratory tests have been developed to detect tumor biomarkers in blood, they lack the ability to identify early-stage cancer since the cancer markers are at extremely low levels that cannot be detected.
Rather, people most often identify they suffer from cancer using invasive biopsies once tumors are found.
Over the past few years, scientists have identified that one of the methods in which cancer cells spread and communicate with other parts of the body is through tiny exosome vesicles in blood or other fluids.
The exosomes vary in size from 40 to 120 nm, or around 1000 times smaller in width compared to a strand of human hair, and are considered to transport molecules from parent cancer cells through the body, entering and then re-programming friendly cells to turn cancerous. More exosome bubbles are secreted by the cancer cells compared to the regular cells.
Exosomes provide a unique opportunity as a cancer marker.
Wenji Dong, Associate Professor, Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University
But it is difficult to detect the cancer-filled exosomes in blood testing. These exosomes resemble the regular cell exosomes and other extracellular bubbles, and in early cancer, they appear at very low levels in the blood.
For the first time, the WSU team applied a technology that makes use of an electric field to quickly segregate, enrich, and detect the exosomes derived from a prostate cancer cell line. The technology was able to concentrate and further isolate the cancer-cell exosomes from those of normal cells by employing the method of immune-binding.
In other words, the team trapped the target exosomes by making use of an antibody specific to a protein marker on the surface of an exosome. Moreover, the team was able to segregate and examine cancer protein markers inside the exosomes.
When compared to the traditional techniques employed in research laboratories to detect and examine exosomes, the new technology was 33 times more sensitive.
This has the potential to become a technique capable of concentrating samples by orders of magnitude in minutes.
Wenji Dong, Associate Professor, Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University
The team was successful in demonstrating the technology using a test serum. At present, they are making efforts to enhance it using a huge amount of human blood that includes a perplexing mix of hormones, lipids, and other elements floating around and could form a challenging setting for viable testing.
Also, the researchers are working to adapt the power needs of the technology, which would enable it to be utilized in a simple and portable manner in a medical setting.
The study was financially supported in part by the National Science Foundation.
Journal Reference:
Guo, S., et al. (2020) Paper-based ITP technology: An application to specific cancer-derived exosome detection and analysis. Biosensors and Bioelectronics. doi.org/10.1016/j.bios.2020.112292.