Just as fly paper captures insects, an innovative new device with nano-sized features developed by researchers at UCLA is able to grab cancer cells in the blood that have broken off from a tumor.
These cells, known as circulating tumor cells, or CTCs, can provide critical information for examining and diagnosing cancer metastasis, determining patient prognosis, and monitoring the effectiveness of therapies.
Metastasis — the most common cause of cancer-related death in patients with solid tumors — is caused by marauding tumor cells that leave the primary tumor site and ride in the bloodstream to set up colonies in other parts of the body.
The current gold standard for examining the disease status of tumors is an analysis of metastatic solid biopsy samples, but in the early stages of metastasis, it is often difficult to identify a biopsy site. By capturing CTCs, doctors can essentially perform a “liquid” biopsy, allowing for early detection and diagnosis, as well as improved treatment monitoring.
To date, several methods have been developed to track these cells, but the UCLA team’s novel “fly paper” approach may be faster and cheaper than others — and it appears to capture far more CTCs.
In a study published this month in the journal Angewandte Chemie, the UCLA team developed a 1-by-2-centimeter silicon chip that is covered with densely packed nanopillars and looks like a shag carpet. To test cell-capture performance, researchers incubated the nanopillar chip in a culture medium with breast cancer cells. As a control, they performed a parallel experiment with a cell-capture method that uses a chip with a flat surface. Both structures were coated with anti-EpCAM, an antibody protein that can help recognize and capture tumor cells.
The researchers found that the cell-capture yields for the UCLA nanopillar chip were significantly higher; the device captured 45 to 65 percent of the cancer cells in the medium, compared with only 4 to 14 percent for the flat device.
“The nanopillar chip captured more than 10 times the amount of cells captured by the currently used flat structure,” said lead study author Dr. Shutao Wang, a postdoctoral researcher at both the Crump Institute for Molecular Imaging at the David Geffen School of Medicine at UCLA and the California NanoSystems Institute at UCLA.