Antibody functionalization of carbon nanotubes for breast cancer applications

Carbon nanotubes (CNTs) are remarkable solid state nanomaterials with unique electrical and mechanical properties. The electronic properties of nanotubes combined with biological molecules, such as proteins, could make miniature devices for biological sensing applications. The interaction of single wall carbon nanotubes (SWNTs) with antibodies is presented. This approach is used towards developing a biosensor for breast cancer detection, by functionalizing the CNTs with antibodies that are specific to cell surface receptors of breast cancer cells. The degree of binding of antibodies on CNTs was found to be 67-88% by confocal microscopy. The key to achieving such a high degree of functionalization is due to the separation of CNTs using surfactants that leads to a high surface-area-to-volume ratio and a higher number of active sites for charge transfer that enhances binding. Further, van der Waals forces and the charges on the antibodies and SWNTs are manipulated to achieve specificity of binding.