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.