"Cluster Bomb" Based on Redox-Responsive Carbon Dot Nanoclusters Coated with Cell Membranes for Enhanced Tumor Theranostics.

Designing intelligent stimuli-responsive nanoplatforms that are integrated with a biological membrane system and nanomaterials to realize efficient imaging and therapy of tumors still remains to be challenging. Herein, we report a unique strategy to prepare redox-responsive yellow fluorescent carbon dot nanoclusters (y-CDCs) loaded with anticancer drug doxorubicin (DOX) and coated with the cancer cell membrane (CCM) for precision fluorescence imaging and homologous targeting chemotherapy of tumors. The y-CDs with a size of 7.2 nm were first synthesized via a hydrothermal method and crosslinked to obtain redox-responsive y-CDCs with a size of 150.0 nm. The formulated y-CDCs were physically loaded with DOX with an efficiency of up to 81.0% and coated with CCM to endow them with antifouling properties, immune escape ability to escape from macrophage uptake, and homologous targeting capability to cancer cells. Within the reductive tumor microenvironment, the y-CDCs with quenched fluorescence can dissociate to form single y-CDs with recovered fluorescence and improved tumor penetration ability and simultaneously release DOX from the "cluster bomb", thus realizing efficient targeted tumor fluorescence imaging and chemotherapy. The designed y-CDCs/DOX@CCM may represent an updated nanomedicine formulation based on CDs for improved theranostics of different types of tumors.