Currently when doctors test for cancer, they often have to take a biopsy, which can require a surgically invasive procedure that can make an already stressful situation even more so for a patient.
Researchers at the University of Michigan have found a way to make this type of test easier for both patients and physicians with a prototype wearable device that can continuously collect live cancer cells directly from a patient’s blood.
The device—which already has been successfully tested in animal models—also could help doctors diagnose and treat cancer more effectively, said Daniel Hayes, a professor of breast cancer research at the University of Michigan Rogel Cancer Center.
|A small wearable device developed by researchers at the University of Michigan has a cancer-cell-capturing chip mounted on top and can be used in place of a biopsy to test patient cells for cancer. The catheter connecting to the patient runs through the hole in the top left corner. (Image source: Tae Hyun Kim, Nagrath Lab, University of Michigan)|
Avoiding a Biopsy
“Nobody wants to have a biopsy,” he said in a U of M news release. “If we could get enough cancer cells from the blood, we could use them to learn about the tumor biology and direct care for the patients. That’s the excitement of why we’re doing this.”
Because a biopsy is not a pleasant experience, doctors currently take just a small sample to test for cancer cells in someone’s bloodstream, taking usually no more than a tablespoon in a single draw. However, this is not always an accurate way to test for cancer, as sometimes even patients with cancer return samples with no cancerous cells.
The device the University of Michigan team developed can take cancer cells directly from the vein, which gives physicians a much higher volume of blood as a testing surface. In tests the team conducted using the device with animal models, the device trapped 3.5 times as many cancer cells per milliliter of blood compared to conventional blood draw samples, researchers said.
The device itself uses a chip to detect immune markers, or antibodies in the blood, and is worn on the wrist and connects to a vein in a person’s arm. It includes protocols for mixing the blood with heparin—a drug that prevents clotting—and sterilization methods that kill bacteria without harming the antibodies on the chip. The device also includes tiny medical-grade pumps in a 3D-printed box with the electronics.
Balancing all of these components in a device that performed as expected was not easy, said Tae Hyun Kim, who earned his PhD in electrical engineering at the University of Michigan and is now a postdoctoral scholar at the California Institute of Technology.
All in a Single Device
“The most challenging parts were integrating all of the components into a single device and then ensuring that the blood would not clot, that the cells would not clog up the chip, and that the entire device is completely sterile,” he said.
The key technology of the device—the chip itself—uses the nanomaterial graphene oxide to create dense clusters of antibody-tipped molecular chains, Kim said. This enables it to trap more than 80 percent of the cancer cells in whole blood that flows across it. The chip can also be used to grow the captured cancer cells, producing larger samples for further analysis, he said.
The team tested the device in dogs at the Colorado State University’s Flint Animal Cancer Center in collaboration with Douglas Thamm, a professor of veterinary oncology and director of clinical research there. To conduct the experiments, they injected healthy adult animals with human cancer cells, which the animals’ immune systems destroy over the course of a few hours with no lasting effects, researchers said. Researchers published a paper on their work in the journal Nature Communications.
It Takes Time
The team plans to continue to work on the device to boost the blood-processing rate, and then will use the improved system to capture cancer cells from pet dogs that are patients at the animal cancer center. To facilitate this, researchers currently are developing chips targeting proteins on the surfaces of canine breast cancer cells.
As for human use, this will take a bit more time, with researchers estimating human trials in three to five years, Hayes said. “This is the epitome of precision medicine, which is so exciting in the field of oncology right now,” he said.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.
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