Recognition and sensitive detection of CTCs using a controllable label-free electrochemical cytosensor

An excellent atomic layer deposition (ALD) method was adopted for the controllable systhesis of a xFe(2)O(3)-nPt (or nPt-xFe(2)O(3))-coated graphene nanostructure (xFe(2)O(3)-nPt@graphene). The produced nanomaterials have been characterized by transmission electron microscopy (TEM), cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). It is shown that xFe(2)O(3) and nPt were effectively tailored and deposited on the graphene. A simple, rapid, and sensitive electrochemical cytosensor based on the controllable nanomaterials was successfully developed for MCF-7 cells detection by combining the high affinity and specificity of an aptamer. The prepared cytosensor displays a linear response to MCF-7 in the concentration range 18 to 1.5x10(6) cell mL(-1) with the detection limit of 6 cell mL(-1) (at an S/N of 3). This cytosensor was applied to detect circulating tumor cells (CTCs) in patient blood and the results were satisfied. The experimental results indicate that the proposed controllable electrochemical cytosensor is highly-sensitive, and convenient for clinical detection of breast CTCs. Graphical abstract