Nanotube Biosensor Arrays for Detection of Molecular Surface Markers in Breast Cancer Cells

Recent reports have shown that nanoscale electronic devices can be used to detect a change in electrical properties when receptor proteins bind to their corresponding antibodies functionalized on the surface of the device, in extracts from as few as ten lysed tumor cells. Here we report a single nanotube field effect transistor arrays, functionalized with IGF1R-specific and Her2-specific antibodies and which exhibits selective sensing of live, intact MCF7 and BT474 human breast cancer cells in human blood. We postulate that the free energy change due to multiple simultaneous cellantibody binding events exerted stress along the nanotube surface, decreasing its electrical conductivity due to an increase in band gap. Because the free energy change upon cell-antibody binding, the stress exerted on the nanotube, and the change in conductivity are specific to a specific antigenantibody interaction, these properties might be used as a fingerprint for molecular sensing of circulating cancer cells.