Microscopic filter captures cancer cells circulating in blood stream
17 December 2012
A microscopic filter that can capture individual tumour cells from
blood has been developed by the RIKEN Advanced Science Institute in
Japan and University of California Los Angeles.
The nanoscale velcro-like filter can capture and release tumour
cells that have broken away from primary tumours and are circulating
in the bloodstream. It could enable detection of tumour cells that
circulate in cancer patients’ blood well before they subsequently
colonize as tumours in other organs.
The device also enables researchers to keep the tumour cells alive
and subsequently study them. It could be used for cancer diagnosis
and give insight into the mechanisms of how cancer spreads
throughout the body. The device also provides a convenient and
non-invasive alternative to biopsy, the current method for diagnosis
of metastatic cancer.
Similar cell-capture devices have been reported but this
technology is unique in that it is capable of catching the tumour
cells with great efficiency and releasing them with great cell
The filter contains a molecule capable of adhering to tumour
cells like Velcro and separating them with efficiency ranging from
40% to 70%. The cancer cells are retained by tiny
temperature-responsive polymer brushes inside the device. At 37°C,
these polymer brushes stick to the tumour cells, but when cooled to
4°C, they release them, allowing
scientists to examine the cells.
Diagram showing how the nanoscale filter operates
"Until now, most devices have demonstrated the ability to capture
circulating tumour cells with high efficiency. However, it is
equally important to release these captured cells, to preserve and
study them in order to obtain insightful information about them.
This is the big difference with our device." Explains Hsiao-hua Yu,
who led the team that developed the technique to coat the device
with polymer brushes.
Shuang Hou et al. Capture and Stimulated Release of Circulating Tumor Cells on Polymer-Grafted Silicon Nanostructures. Advanced