▎ 摘　　要

We demonstrated that the fine control over the surface charge density of chemically converted-graphene (CCG) is possible via salt "invasion", resulting in the formation of self-assembled stacked-CCG colloids in solution, which can serve as powerful building blocks for the capturing of DNAs independent of their structure that are not available to traditional colloidal graphene-based materials, thus providing our new insight into graphene/DNA interaction. Furthermore, the self-assembled biocomposites exhibit high stability even in saline solution (0.4 M NaCl) and can function as ideal components for real-time assay for screening genotoxic chemicals, not only avoiding the complex layer-by-layer assembly in comparison with those of conventional electrochemistry-based sensors, but also improving the signal transduction. We envision that the stacked-CCG, a novel type of colloidal graphene-derived material, could open new opportunities for the rational design of multifunctional graphene-based biocomposites and provide a brand new avenue in biosensing, drug screening and genotoxicity screening in the future.