Tantalum oxide nanoparticles as an advanced platform for cancer diagnostics: a review and perspective

Abstract

The development of new safe and effective contrast agents (CAs) is a crucial factor to increase the effectiveness of computed tomography (CT). For now, tantalum oxide-based nanoparticles (TaO_x NPs) are among the most promising CAs for CT due to their superior properties: high X-ray attenuation coefficient, excellent biocompatibility, and easily modifiable surface chemistry. Compared to the commercially available analogs (iodine-based CAs), TaO_x NPs provide better contrast performance, long-circulation, and high safety profiles (reduced exposure of X-rays and CA dosage). Among the investigated nanoparticulate CAs they afford higher cost-effectiveness (Au, Pt, Lu). TaO_x NPs can also be easily modified to include other imaging or therapeutic modalities. This review aims to summarize the current state-of-the-art knowledge in the field of tantalum oxide-based CAs used for single or multimodal imaging and theranostic purposes. The design specification of TaO_x NPs in terms of size, surface functionalization, composition, and their influence on the contrast performance, toxicity, and pharmacokinetics are discussed. Finally, the future opportunities and challenges of TaO_x NPs used as CT CAs are addressed.