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that they have no competing interests. Authors’ contributions JL participated in the design of the study, carried out the experiments, and drafted the manuscript. SYR and JK carried out the sample preparation and measurements. YJ supervised the work. All authors read and approved the final manuscript.”
“Background Since discovered by Andre Geim and Konstantin 4SC-202 chemical structure Novoselov in 2004 [1], graphene has drawn significant attention to different scientific

and technical communities due to its unique electrical, chemical, mechanical, optical, and structural properties [2]. However, large-area graphene remains to be a metallic conductor even at the neutrality point which limits its application in nanoelectronic devices and biological science [3–6]. In addition, for the purpose of drug delivery and biological nanoprobe applications, small-sized graphene or graphene oxides (GOs) can easily be swallowed into organs, tissues, and cells [7]. Recently, quite a lot of researchers have reported about the preparation of graphene ribbons with quantum confinement and edge effect properties by directly tailoring large-area graphene via e-beam lithography [8], hydrogen plasma etching [9], scanning tunneling microscope lithography [10], atomic force

microscopy [11], chemical stripping, Inositol monophosphatase 1 or catalytic tailoring (Fe, Ni, and Co nanoparticles as catalysts) [12–16]. Usually, the technologies used for synthesis of graphene ribbons mostly must be operated under ultrahigh-vacuum and high-energy conditions. So it is very difficult to produce large quantities of water-soluble graphene pieces. Moreover, these extreme synthetic conditions will be ultimately bound to affect the properties of graphene ribbon. Till now, direct soluble-phase formation of nanoscale graphene or graphene oxide pieces has been rarely involved [17]. Generally, through selecting small-sized graphite as raw materials to control the size of GO during the synthesis of GO through the Hummers procedure, subsequently complicated treatment with strong sonication treatment and stepwise centrifugation at 4,000 to 10,000 rpm, a small-sized GO can be obtained [18]. However, the procedures are quite complex and the yield of nanoscale fragments is also very low.