Hierarchically Targeted and Penetrated Delivery of Drugs to Tumors by Size‐Changeable Graphene Quantum Dot Nanoaircrafts for Photolytic Therapy

Theranostic nanohybrids are promising for effective delivery of therapeutic drug or energy and for imaging-guided therapy of tumors, which is demanded in personalized medicine. Here, a size-changeable graphene quantum dot (GQD) nanoaircraft (SCNA) that serves as a hierarchical tumor-targeting agent with high cargo payload is developed to penetrate and deliver anticancer drug into deep tumors. The nanoaircraft is composed of ultrasmall GQDs (less than 5 nm) functionalized with a pH-sensitive polymer that demonstrates an aggregation transition at weak acidity of tumor environment but is stable at physiological pH with stealth function. A size conversion of the SCNA at the tumor site is further actuated by near-infrared irradiation, which disassembles 150 nm of SCNA into 5 nm of doxorubicin (DOX)/GQD like a bomb-loaded jet, facilitating the penetration into the deep tumor tissue. At the tumor, the penetrated DOX/GQD can infect neighboring cancer cells for repeated cell killing. Such a SCNA integrated with combinational therapy successfully suppresses xenograft tumors in 18 d without distal harm. The sophisticated strategy displays the hierarchically targeted and penetrated delivery of drugs and energy to deep tumor and shows potential for use in other tumor therapy.