Atomically Precise Water-Soluble Graphene Quantum Dot for Cancer Sonodynamic Therapy

Although water-soluble graphene quantum dots (GQDs) have shown various promising bio-applications due to their intriguing optical and chemical properties, the large heterogeneity in compositions, sizes, and shapes of these GQDs hampers the better understanding of their structure-properties correlation and further uses in terms of large-scale manufacturing practices and safety concerns. It is shown here that a water-soluble atomically-precise GQD (WAGQD-C₉₆ ) is synthesized and exhibits a deep-red emission and excellent sonodynamic sensitization. By decorating sterically hindered water-soluble functional groups, WAGQD-C₉₆ can be monodispersed in water without further aggregation. The deep-red emission of WAGQD-C₉₆ facilitates the tracking of its bio-process, showing a good cell-uptake and long-time retention in tumor tissue. Compared to traditional molecular sonosensitizers, WAGQD-C₉₆ generates superior reactive oxygen species and demonstrates excellent tumor inhibition potency as an anti-cancer sonosensitizer in in vivo studies. A good biosafety of WAGQD-C₉₆ is validated in both in vitro and in vivo assays.