Abstract
In order to acquire well dispersed graphene solution, we chose electrochemical exfoliation method to synthesize graphene. In this method, poly sodium 4-styrenesulfonate was bound on graphene during the process, therefore improve the hydrophilicity of graphene and prevent it from re-stacking by strong Van der Waals interaction. This method offers advantages such as low process temperature, low cost, and rapid and efficient graphene fabrication. Also, the polymer is biocompatible and thus suitable for biomedical application. To evaluate possible applications of graphene in vivo, this study conducted irritation and toxicity tests of graphene synthesized by the exfoliation method. First, skin irritation test on rabbits reveals that graphene did not cause any skin irritation and corrosion even in a long exposure time up to 24 h. Eye irritation test indicates that graphene could neither cause eye irritation nor induce corneal ulcer. On the other hand, mouse after tail vein injection of graphene at a high concentration showed acute abnormality of liver function on day 1, although the liver function result dropped to normal range on day 7. Histopathology analysis of tissue section uncovered that after injection of high dose graphene, there were obvious accumulates of graphene found in lung, liver, and spleen, and could be retained by these organs till 90 days post injection. In order to trace the distribution of graphene in mice after intravenous injection, in vivo and in situ image system was applied to acquire fluorescence images at different time points post injection. It shows that graphene is widely distributed in the entire mouse within one minute, and tends to retain in liver and bladder after one day.