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Nano “Fly Paper” Captures Metastatic Cancer Cells for Testing

Just as fly paper captures insects, an innovative new device with nano-sized features developed by researchers at UCLA is able to capture 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. 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. 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 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 time required for CTC detection using CellSearch, a technology currently approved by the U.S. Food and Drug Administration, is upwards of three to four hours, according to one of the UCLA study authors, Dr. Hao Wang. The UCLA study found an optimal detection time of only two hours using nanopillar chips. "We hope that this platform can provide a convenient and cost-efficient alternative to CTC sorting by using mostly standard lab equipment," said senior study author Dr. Hsian-Rong Tseng. This report was published in the November 9 issue of Angewandte Chemie. [Press release] [AC abstract]