Facile one-pot synthesis of folic acid-modified graphene to improve the performance of graphene-based sensing strategy.

A convenient and environment-friendly method is reported to synthesize the reduced graphene oxide (rGO) sheets in aqueous solution using folic acid (FA) as both a reducing and stabilizing agent, to improve the performance of graphene-based sensing strategy. The as-prepared FA-rGO sheets were characterized by transmission electron microscopy (TEM), UV-vis absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA), which provided the clear identification of the removal of oxygen-containing functional groups from the graphene oxide (GO) to form FA-rGO sheets. Further, it was found that the obtained FA-rGO sheets exhibited better biocompatibility and could act as the more efficient energy acceptor in long range resonance energy transfer (LrRET) process than that of graphene. Additionally, the FA-rGO can also catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2, and compared with GO sheets, they exhibited the more prominent intrinsic peroxidase-like activity, thus providing the more sensitive approach for colorimetric detection of H2O2.