A team of researchers from the University of Alberta, Canada, has demonstrated that applying intense ultrasound—at levels much higher than used for imagining—can cause the release of biomarkers from cells, allowing for earlier detection of cancer via liquid biopsy. Their work was presented today at the Acoustical Society of America and the Canadian Acoustical Association, being held this week in Ottawa.
“Ultrasound, at exposure levels higher than is used for imaging, can create tiny pores in cell membranes, which safely reseal,” said Roger Zemp, PhD, associated professor of in the Electrical and Computer Engineering at University of Alberta. “This process is known as sonoporation. The pores formed due to sonoporation were previously used to get drugs into cells and tissues. In our case, we care about releasing the contents of cells for diagnostics.”
Zemp’s laboratory focuses on the use of biomedical imaging, such as biomedical optics and biomedical ultrasound, with a focus on discovering new methods and technologies to deliver insights that are currently difficult to obtain. But a portion of the lab’s research also focuses on how to use these technologies to improve drug and gene delivery to cells, with most of the same techniques applicable to amplifying the population of available diagnostic biomarkers.
The lab also has a program that seeks to employ photoacoustic imaging of gene expression and is developing absorption-based reporter gene systems for that purpose.
According to Zemp, the application of the more intense ultrasound to allow material to pass from cells into the bloodstream increases the concentration of genetic material in the blood to high enough levels to be detection by conventional testing methods. The method has the potential to eliminate more invasive tissue biopsies and could be used both as a first diagnosis as well as to monitor treatment efficacy and/or disease progression.
“Ultrasound can enhance the levels of these genetic and vesicle biomarkers in blood samples by over 100 times,” Zemp said. “We were able to detect panels of tumor-specific mutations, and now epigenetic mutations that were not otherwise detectable in blood samples.
“We’ve also found that we can conduct ultrasound-aided blood testing to look for circulating tumor cells in blood samples with single-cell sensitivity for the price of a COVID test,” he added. “This is significantly cheaper than the current methods, which cost about $10,000 per test.”
In addition to providing ultrasound at levels that will induce sonoporation, Zemp and the team have also demonstrated the potential to use targeted ultrasound liquify small volumes of tissue to allow for biomarker detection. The liquefied tissue can also be collected from the blood less invasively using a fine-needle syringe compared with core needles needed for current biopsy methods.
The technique could become an important method for oncologist who are monitoring disease return or progression to metastatic disease by providing an earlier view of when cancer returns allowing for earlier—and targeted—treatment.
