Encapsulating tantalum oxide into polypyrrole nanoparticles for X-ray CT/photoacoustic bimodal imaging-guided photothermal ablation of cancer

A nanotheranostic agent has been readily fabricated by encapsulating tantalum oxide (TaOx) nanoparticles (NPs) into polypyrrole (PPy) NPs via a facile one-step chemical oxidation polymerization for bimodal imaging guided photothermal ablation of tumor. It was proved that the obtained composite nanoparticles (TaOx@PPy NPs) with an average diameter around 45 nm could operate as an efficient bimodal contrast agent to simultaneously enhance X-ray CT and photoacoustic (PA) imaging greatly in vivo. Systemically administered TaOx@PPy NPs could passively accumulate at the tumor site during the blood circulation, which was proved by both CT and PA imaging. In addition, the in vivo therapeutic examinations showed that TaOx@PPy NPs exhibited significant photothermal cytotoxicity under near infrared laser irradiation. The tumor growth inhibition was evaluated to be 66.5% for intravenously injection and 100% for intratumoral injection, respectively. This versatile agent can be developed as a smart and promising nanoplatform that integrates multiple capabilities for both accurate diagnosing and precise locating of cancerous tissue, as well as effective photoablation of tumor.