▎ 摘　　要

In vivo assays of graphene and its derivatives are big challenges in biological evaluations because they require simultaneous long-term stability in aqueous dispersion and controllable systemic toxicity. Bifunctional graphene nanosheets which have key function in biomedical area are expected to address this challenge. Here, novel bifunctional graphene nanosheets were successfully synthesized in the presence of Herceptin, a natural antibody, using a facile ultrasonic-assisted method. Graphite layers were successfully exfoliated which resulted excellent stability of separated layers in herceptin solution. In aqueous solution, graphene concentration was effectively controlled by varying the herceptin content and sonication time. Furthermore, the toxicity of graphene was tested in both 2D and 3D spheroid cultures. The results showed that graphene toxicity were considerably reduced in spheroid culture compared to the 2D culture data. Moreover, the toxicity behavior of graphene was dependent on the exposed concentration of graphene that the mortality rate was significantly decreased when the concentration of graphene was below 1 mu g/mL. This bifunctional graphene which possessed long-term stability in aqueous solutions and induced slight toxicity offers a promising nanostructure in tumor-targeted drug delivery, regenerative medicine and tissue engineering. This proof-of-concept study demonstrates the feasibility of ultrasonic assisted method in one-step synthesis of bifunctional nanomaterials and biostructures for clinical applications.