[Image from the University of Michigan]
Cancer cells are typically captured from blood samples from a patient, which is no more than a tablespoon of blood taken in a single draw. The blood sometimes has no cancer cells and blood samples from patients who have advanced cancer have no more than 10 cancer cells.
“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,” Dr. Daniel Hayes, professor of breast cancer research at the University of Michigan and senior author on the paper, said in a press release.
The new device could continuously capture cancer cells from the vein. So far, tests have shown that the chip was able to trap 3.5 times as many cancer cells per milliliter of blood compared to other blood draw samples.
“It’s the difference between having a security camera that takes a snapshot of a door every five minutes of takes a video. If an intruder enters between the snapshots, you wouldn’t know about it,” Sunitha Nagrath, associate professor of chemical engineering at the University of Michigan, said.
The device was tested on dogs at Colorado State University where human cancers cells were injected into the dogs. The blood cells were eliminated by the dog’s immune system over a few hours with no lasting effects. The dogs were given a mild sedative two hours after the cancer cells were injected and the device was connected to the dogs. The device screened 1-2% of their blood and had blood drawn every 20 minutes. Blood samples were collected by a chip of the same design.
Designed as a wearable device for the wrist, the University of Michigan-developed device reduces the size of traditional cancer cell collecting machines that are typically the size of an oven.
“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,” Tae Hyun Kim, a researcher on the project said.
Heparin, a drug that prevents clotting, was used to mix the blood, as well as sterilization methods that could kill bacteria without damaging cell-targeting immune markers on the device’s chip. Medical-grade pumps were also packaged within a 3D printed box with the device’s electronics and the cancer cell capturing chip.
The chip is made from nonmaterial graphene oxide to make antibody-tipped molecular chains to trap more than 80% of cancer cells. The researchers could also use the chip to grow captured cancer cells to make larger samples to analyze.
The researchers now plan to increase the blood processing rate and use the system to capture cancer cells from pet dogs that come to the cancer center as patients. They also suggest that the device could start being used in human trials in three to five years to help optimize cancer treatment in humans.
“This is the epitome of precision medicine, which is so exciting in the field of oncology right now,” said Hayes.
The research was published in the journal Nature Communications.
