▎ 摘　　要

A highly sensitive and selective tumor cell sensor based on partially oxidized graphene (POG) and folate acid (FA) composite was constructed. The POG was prepared through a modified Hummers method and characterized by means of Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, atomic force microscopy and transmission electron microscopy. The as-prepared POG exhibited the advantages of high electrochemical activity and a good capacity of linking amine derivatives. Using a facile one step reaction, the FA-modified POG was endowed with a more sensitive response to folate-expressing tumor cells than those sensors constructed by the two-step reaction, as well as high selectivity, good reproducibility and long-term stability.