Biodegradation of graphene-based nanomaterials in blood plasma affects their biocompatibility, drug delivery, targeted organs and antitumor ability.

The extensive use of graphene-family nanomaterials (GFNs) in biomedicine and other fields has intentionally or unintentionally resulted in their introduction into the blood circulation system, but the effects of the biotransformation of GFNs in blood plasma on their biocompatibility, organ targeting, drug delivery and antitumor ability remain unclear. The present work discovered that GFN sheets were degraded in human blood plasma to holey sheets and aromatic hydrocarbons. The carbon atoms connected with oxygen-containing groups in the planes of GFNs were the initial attack sites for active substances (e.g., OH and O2-) in blood plasma. Subsequently, CC/CC bonds were broken. The reaction rate depended strongly on the extent of oxidization of GFNs. The pristine GFNs caused secondary structure damage to proteins and disturbances of cellular metabolic pathways. In contrast, the biotransformed nanomaterials presented high biocompatibility and were located in and targeted different tissues from their pristine forms, which influenced specific organ targeting therapy. The biotransformed nanomaterials also exhibited higher efficiencies of drug delivery (drug release and location) and killing tumor cells in vitro and in vivo. These findings provide insights into the application of nanomaterials in human healthcare using biotransformed nanomaterials.