Carboxymethyl chitosan-functionalized graphene for label-free electrochemical cytosensing

Here we demonstrate the fabrication of an effective cytosensor using carboxymethyl chitosan-functionalized graphene (CMC-G) prepared through chemical reduction of graphene oxide. The CMC-G hybrid was further characterized with UV–vis spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, transmission electron microscopy and atomic force microscopy. Layer-by-layer assembly of CMC-G with polyethyleneimine and folic acid enabled the fabrication of a label-free electrochemical impedance spectroscopy cytosensor with high stability and biocompatibility. The proposed cytosensor exhibited good electrochemical behavior and cell-capture ability for HL-60 cells, and showed a wide linear range and low detection limit for quantification.