Tumors can release more than 1,000 cancer cells into the bloodstream in a single minute. Current methods of capturing cancer cells from blood rely on samples from the patient — usually no more than a tablespoon taken in a single draw. Some blood draws come back with no cancer cells, even in patients with advanced cancer, and a typical sample contains no more than 10 cancer cells.
A prototype wearable device was developed that can continuously collect live cancer cells directly from a patient’s blood. Over a couple of hours in the hospital, the device could continuously capture cancer cells directly from the vein, screening much larger volumes of a patient’s blood. In tests, the cell-grabbing chip in the wearable device trapped 3.5 times as many cancer cells per milliliter of blood compared to the traditional blood draw samples.
Research shows that most cancer cells can’t survive in the bloodstream, but those that do are more likely to start a new tumor. Typically, it is these satellite tumors, called metastases, that are deadly, rather than the original tumor. This means cancer cells captured from blood could provide better information for planning treatments than those from a conventional biopsy.
The device shrinks a machine that is typically the size of an oven down to something that could be worn on the wrist and connected to a vein in the arm. Protocols were developed 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. Some of the smallest medical-grade pumps were packaged in a 3D-printed box with the electronics and the cancer-cell-capturing chip.
The chip 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.
In the next steps for the device, the team hopes to increase the blood processing rate. The device could begin human trials in three to five years. It would be used to help to optimize treatments for human cancers by enabling doctors to see if the cancer cells are making the molecules that serve as targets for many newer cancer drugs.