A team led by Hsiao-hua Yu, RIKEN Advanced Science Institute, Japan, and Hsian-Rong Tseng, University of California Los Angeles, USA, report a new nanoscale device that captures and releases tumor cells that have broken away from primary tumors and are circulating in the bloodstream.

Thermally responsive biotin-functionalized polymer brushes (i.e., poly(N-isopropylacrylamide) (PIPAAm)) are covalently grafted onto silicon nanowire substrates (SiNWS). Blood is passed through a device like a filter that contains these molecules. The cancer cells are retained by the brushes. This platform demonstrates superior performances in capturing cancer cells with high efficiency at 37 °C, and releasing the captured cancer cells with great viability and retained functionality at 4 °C.

The device provides a convenient and non-invasive alternative to biopsy, the current method for diagnosis of metastatic cancer. It could enable doctors to detect tumor cells that circulate in cancer patients’ blood well before they subsequently colonize as tumors in other organs. Similar cell-capture devices have been reported but this technology is unique in that it is capable of catching the tumor cells with great efficiency and releasing them with great cell viability, so that the researchers can study them.

• Capture and Stimulated Release of Circulating Tumor Cells on Polymer-Grafted Silicon Nanostructures,
  Shuang Hou, Haichao Zhao, Libo Zhao, Qinglin Shen, Kevin S. Wei, Daniel Y. Suh, Aiko Nakao, Bin Xiong, Shyh-Chyang Luo, Hsian-Rong Tseng, Hsiao-hua Yu,
  Adv. Mat. 2012.
  DOI: 10.1002/adma.201203185