Delivery of a chemotherapeutic drug using novel hollow carbon spheres for esophageal cancer treatment.

Low toxicity and high efficacy are the key factors influencing the real-world clinical applications of nanomaterial-assisted drug delivery. In this study, novel hollow carbon spheres (HCSs) with narrow size distribution were developed. In addition to demonstrating their ease of synthesis for large-scale production, we also demonstrated in vitro that the HCSs possessed high drug-loading capacity, lower cell toxicity, and optimal drug release profile at low pH, similar to the pH in the tumor microenvironment. The HCSs also displayed excellent immunocompatibility and could rapidly distribute themselves in the cytoplasm to escape lysosomal clearance. More importantly, the HCSs could efficiently deliver doxorubicin (a representative chemotherapeutic drug) to tumor sites, which resulted in significant inhibition of tumor growth in an esophageal xenograft cancer model. This also prolonged the circulation time and altered the biodistribution of the drug. In conclusion, this study revealed a novel drug delivery system for targeted tumor therapy.