A new immunosensor for breast cancer cell detection using antibody-coated long alkylsilane self-assembled monolayers...

We designed a new efficient and reliable immunosensor and demonstrated its analytic performance to capture breast cancer MCF7 and T47D cells, under laminar flow, onto antibody-coated long alkylsilane self-assembled monolayers (SAMs) in a parallel plate flow chamber. The surface floor of the laminar flow chamber was grafted with an amino-terminated long alkyl chain spacer, 21-aminohenicosyl trichlorosilane (AHTS) followed by tethering a specific monoclonal antibody directed against the human epithelial cell adhesion molecule (EpCAM) antigen, which is overexpressed in primary breast cancer. Properties of the AHTS- and antibody-grafted surface floor were compared to that of surface floors coated with the short alkyl spacers 3-glycidoxy-propyl trimethoxysilane (GPTS) or 3-aminopropyl triethoxysilane (APTES) and antibodies. A theoretical model was constructed according to the geometry of the flow chamber in order to calculate the trajectories that would use cell flows. Cell capture experiments demonstrated that cell immobilization was optimized throughout the whole flow chamber. High cell capture was yielded on antibody-tethered long alkyl AHTS surface. This new procedure offers multiple advantages: a versatile tool readily applied to a panel of purified antibodies, an enrichment of cell immobilization using repetitive cell flow, and a stable capturing surface suitable for long term storage and handling.