Scheme 1

Schematic representation of the integrated fabrication of 3D cytosensor and electrochemical detection of CTCs. a–f Fabrication procedure of the Ni micropillars on the ITO glass. g Fabrication of electrospun PLGA nanofibers on Ni micropillars. h CTCs were captured and i QDs-anti-EpCAM antibody conjugates were recognized. j The amplification of captured CTC and k SEM image of CTC in microenvironment. m, n Principles of electrochemical assay