Pharmaceutical Formulations

Carbon dots (C-Dots) with diameter smaller than 10 nm have recently attracted enormous attention in various fields due to their unique properties. In this talk, the synthesis, characterization and bioapplications of a new type of nontoxic, water-soluble C-Dots will be presented. A major medical challenge one faces to treat Central Nervous System (CNS) related diseases is to cross the tight junctions between endothelial cells, which are known as blood-brain barrier (BBB). Recently, our in vivo experimental observations suggested that the transferrin conjugated C-Dots could enter the CNS of Zebrafish while C-Dots alone could not. Thanks to the abundant presence of carboxylic acids on the surface, CDots are easily conjugated with transferrin and anticancer drug doxorubicin. The system was then applied as a drug delivery system for the delivery of

doxorubicin into cancerous cells. Our in vitro study showed greater uptake of the conjugates compared to free doxorubicin, the conjugates at 10 nM was significantly more cytotoxic than doxorubicin alone, reducing viability by 14-45 %, across multiple

pediatric brain tumor cell lines. Accidents, disease and aging compromise the structural and physiological functions of bones, and in vivo bone imaging test is critical to identify, detect and diagnose bone related development and dysfunctions. Here we show that C-Dots with low quantum yield ("dark") bind to calcified bone structures of live Zebrafish larvae with high affinity and selectivity. Binding resulted in a strong enhancement of luminescence that was not observed in other tissues, including non-calcified endochondral elements. Retention of Cdots by bones was very stable, long lasting, and with no detectable toxicity. These observations support a novel and revolutionary use of C-Dots as highly specific bioagents for bone imaging and diagnosis, and as a potential bone-specific drug delivery carrier.