University of Michigan researchers have recently created a wearable device that can continuously collect and examine circulating tumor cells (CTCs) in the blood. These cancer cells are typically obtained via blood samples to provide a biomarker for treatment, but this wrist-worn prototype could potentially screen patients’ blood for a few hours to obtain only the CTCs of interest. These findings were published today in a Nature Communications paper.
The blood draws typically used to identify and analyze these CTCs are commonly limited by insufficient CTC counts in the sample in addition to the negative health impacts of removing blood from a patient with cancer. Taking a biopsy sample from the patient is another common method to detect cancers, but these biopsy procedures can often be more invasive than a patient would prefer. By continuously monitoring the patient’s blood for the specific CTCs of interest, this wearable device could offer an extremely convenient means of detecting cancers.
“Nobody wants to have a biopsy,” said senior author Dr. Daniel F. Hayes, professor at the University of Michigan Rogel Cancer Center. “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.”
The paper describes the device to be composed of a micro-controller, a peristaltic pump, a heparin injector, and a CTC capture module equipped with a microfluidic capture chip. The whole system is contained within a 3D printed casing and is controlled wirelessly through a corresponding app.
When outfitted to the patient, venous blood is taken up by the device through an intravenous catheter then replenished into the bloodstream. This method lets the device analyze a significantly larger quantity of blood while minimizing blood lost in the process.
“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,” said lead author Tae Hyun Kim, a postdoctoral scholar at the California Institute of Technology.
The technology showed promising results in a canine study, with the device capturing 3.5 times as many cancer cells per milliliter of blood than the traditional blood drawing method. The animals were injected with human cancer cells that were eliminated by the dogs’ immune system in a matter of hours, yielding no long-term effects.
In the first two hours after injection, the dogs were given mild sedatives and connected to the wearable, which screened 1-2 percent of their blood. Simultaneously, blood was drawn from the dogs and analyzed 20 minutes to compare the device to conventional screening methods. Hayes is confident the wearable could be tested in humans within the next three to five years.
“This is the epitome of precision medicine, which is so exciting in the field of oncology right now,” says Hayes.
— Michigan Engineering (@UMengineering) April 1, 2019