|The CTC purification system is capable of controlling the temperature like an espresso machine for blood to capture then release the cancer cells in great purity.
Image: Courtesy of Dr. Hsian-Rong Tseng
UCLA scientists have led an international group in developing a new method for effectively extracting and analyzing cancer cells circulating in patients’ blood. Capturing these rare cells would allow doctors to detect and analyze the cancer so they could tailor treatment for individual patients.
In his laboratory at the UCLA California NanoSystems Institute, Hsian-Rong Tseng, PhD, professor of molecular and medical pharmacology, used a device he invented to capture circulating tumor cells from blood samples. The device, called the NanoVelcro Chip, is a postage-stamp–sized chip with nanowires that are 1,000 times thinner than a human hair and are coated with antibodies that recognize circulating tumor cells. When 2 milliliters of blood are run through the chip, the tumor cells stick to the Velcro-like nanowires.
Capturing the tumor cells was just part of the battle, though. To analyze them, Dr. Tseng’s team needed to be able to separate the cells from the chip without damaging them.
In earlier experiments with NanoVelcro, the scientists used a technique called laser capture microdissection that was effective in removing individual cells from the chip without damaging them, but the method was time-consuming and labor intensive, and it required highly specialized equipment.
Now, Dr. Tseng and his colleagues have developed a thermoresponsive NanoVelcro purification system, which enables them to raise and lower the temperature of the blood sample to capture (at 37 degrees Celsius) and release (at 4 degrees Celsius) circulating tumor cells at their optimal purity. Polymer brushes on the NanoVelcro’s nanowires respond to the temperature changes by altering their physical properties, allowing them to capture or release the cells. Because it could make extracting the cancer cells much more efficient and cost-effective at a time in a patient’s life when information is needed as quickly as possible, Dr. Tseng says it is conceivable that the new system will replace laser capture microdissection as the standard protocol.
“With our new system, we can control the blood’s temperature — the way coffeehouses would with an espresso machine — to capture and then release the cancer cells in great purity,” says Dr. Tseng, who also is a member of UCLA’s Jonsson Comprehensive Cancer Center. “We combined the thermoresponsive system with downstream mutational analysis to successfully monitor the disease evolution of a lung-cancer patient. This shows the translational value of our device in managing non-small-cell lung cancer with underlying mutations.”
"Nanostructure Embedded Microchips for Detection, Isolation and Characterization of Circulating Tumor Cells,” ACS Nano, August 11, 2014