▎ 摘　　要

We applied a fluorescein-containing oligonucleotide ( ON) to probe surface properties of oxidized graphene ( oxo-G) and observed that graphene-like patches are formed upon aging of oxo-G, indicated by enhanced probe binding and by FTIR spectroscopic analysis. By using a recently developed fluorogenic endoperoxide ( EP) probe, we confirmed that during the aging process the amount of EPs on the oxo-G surface is reduced. Furthermore, aging was found to strongly affect cell membrane carrier properties of this material. In particular, freshly prepared oxo-G does not act as a carrier, whereas oxo-G aged for 28 days at 4 degrees C is an excellent carrier. Based on these data we prepared an optimized oxo-G, which has a low-defect density, binds ONs, is not toxic, and acts as cell membrane carrier. We successfully applied this material to design fluorogenic probes of representative intracellular nucleic acids 28S rRNA and beta-actin-mRNA. The results will help to standardize oxidized graphene derivatives for biomedical and bioanalytical applications.