Circulating tumor cells (CTCs) cause metastases of cancer, but they might have a redeeming quality if we could use them as biomarkers for those very cancers. For most neoplasms, biopsies are performed to definitively diagnose the disease, but circulating tumor cells offer the possibility of “liquid biopsies” that only require the sampling of blood.
Researchers at University of Michigan have now developed a wearable device that can continuously screen whole blood for CTCs and make those available for inspection by pathologists.
“Nobody wants to have a biopsy. 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,” said Daniel F. Hayes, M.D., senior author of the study, in a statement.
Capturing CTCs is difficult because of how rare they are. Typically, a blood sample is taken and a highly sensitive device is used to identify the few CTCs within that sample. The new device from U of M stays with the patient over a long time, so it has a chance to use effectively a lot more blood for its sample.
Moreover, because the tumor doesn’t always release the same amount of CTCs, a sample taken at any given time may have too few of the target cells to find. The new device can take samples as often as is required, which should help avoid issues of accuracy related to the timing of blood draws.
So far the technology was tried in dogs which were given injections of human CTCs (don’t worry, this didn’t lead to cancer in these dogs). The wearable device was set to take samples every 20 minutes and indeed it did spot the CTCs. It was small enough for the dogs to wear over a period of hours, and could be made into a simple wrist strap that a patient can wear.
Some details about what the research team had to do to achieve this latest development, according to U of M:
They developed protocols for mixing the blood with heparin, a drug that prevents clotting, and sterilization methods that killed bacteria without harming the cell-targeting immune markers, or antibodies, on the chip. Kim also packaged some of the smallest medical-grade pumps in a 3D-printed box with the electronics and the cancer-cell-capturing chip.
The chip itself is a new twist on one of the highest-capture-rate devices from Nagrath’s lab. It uses the nanomaterial graphene oxide to create dense forests of antibody-tipped molecular chains, enabling 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.
Study in Nature Communications: A temporary indwelling intravascular aphaeretic system for in vivo enrichment of circulating tumor cells…
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