Nanotube Biosensor Arrays for Detection of Molecular Surface Markers in Breast Cancer Cells
B. Panchapakesan, E. Wickstrom
University of Louisville, US
Keywords: nanotube, cancer, IGF1R, HEr2
Abstract: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. We report for the first time a single nanotube field effect transistor array, functionalized with IGF1R-specific and Her2-specific antibodies, which exhibits highly sensitive and selective sensing of live, intact MCF7 and BT474 human breast cancer cells in human blood. Those two cell lines both overexpress IGF1R and Her2, at different levels. Single nanotube devices that were functionalized with IGF1R-specific or Her2-specific antibodies showed 60% decreases in conductivity upon interaction with BT474 or MCF7 breast cancer cells in two-microL drops of blood. Control experiments with non-specific antibodies or with MCF10A control breast cells produced less than 5% decrease in electrical conductivity, illustrating the high sensitivity for whole cell binding by these single nanotube-antibody devices. We postulate that the free energy change due to multiple simultaneous cell-antibody binding events exerted stress along the nanotube surface, decreasing its electrical conductivity due to an increase in band gap.