July 6 (UPI) -- Scientists have developed a method for separating circulating tumor cells, or CTCs, from blood samples quickly, which they say could help speed cancer diagnosis.
In a new study, published this week in the journal Small, scientists from Duke University, MIT and Nanyang Technological University in Singapore demonstrate a platform based on sound waves to separate CTCs from a 7.5-ml vial of blood. The process took less than an hour and succeeded with 86 percent efficiency.
The stray tumor cells are known as circulating tumor cells, which are small pieces of a tumor that break away and flow through the bloodstream. They contain information about the tumor, such as its type, physical characteristics and genetic mutations that can help doctors with prognosis and determining the most effective treatments.
The ability to quickly harvest and grow CTCs from a blood sample would enable "liquid biopsies" that could provide a reliable method diagnosis, prognosis and treatment suggestions based on CTC profiling, the researchers say.
"Biopsy is the gold standard technique for cancer diagnosis, but it is painful and invasive and is often not administered until late in the cancer's development," Tony Jun Huang, the William Bevan Professor of Mechanical Engineering and Materials Science at Duke University, said in a press release.
With the team's CTC separation technology, they could find out whether the patient has cancer, where the cancer is located, what stage it's in and which drugs would work best from a small sample of blood instead of invasive surgery, he said.
CTCs are rare and difficult to catch. There are typically only a handful for every few billion blood cells running through a persom's veins, and the many technologies designed to separate them from normal blood cells are flawed. Most damage or kill the cells in the process, lack efficiency, only work on specific types of cancer or take too long to be used in many situations.
The technology works by placing a standing sound wave at an angle to a the fluid flowing through a channel, and the pressure of the sound wave pushes cancer particles in the liquid -- they are larger and more firm than blood cells -- into a separate channel to be collected for analysis.
The sound waves are similar to those in ultrasonic imaging, and there's less risk of damage to the CTCs because each cell experiences the acoustic wave for only a fraction of a second and does not require labeling or surface modification.
The approach was first demonstrated three years ago and has been improved enough to be used in a clinical setting.
With additional improvements to the method, researchers hope the technology will form the basis of a new test through an inexpensive, disposable chip, researchers say.