Tantalum

The Bonitatibus group is advancing CT diagnostics with the development of a next-generation x-ray contrast agent to overcome the fundamental limitations of current iodinated media. Clinical CT has relied on small-molecule iodine agents for decades, but these suffer from poor performance in obese patients, rapid vascular washout, and safety limitations in patients with kidney disease or contraindications. To address this unmet need, we have designed a purpose-built nanoparticle system: the carboxybetaine zwitterionic tantalum oxide nanoparticle (TaOx NP).

TaOx NP combines three engineered features to deliver superior imaging performance: a tantalum oxide core chosen for its strong x-ray attenuation and clinical biocompatibility, a zwitterionic polymer shell designed for rapid renal clearance with minimal tissue retention, and a ~3.1 nm size optimized for both extended blood-pool imaging and efficient elimination. This rational design produces an autoclave-stable, injectable agent with an expanded diagnostic window and excellent safety profile. Preclinical studies have demonstrated low organ retention (<2% at 48 hours), rapid urinary excretion, and no evidence of cytotoxicity, hemolysis, or inflammation at doses far exceeding anticipated clinical use.

Performance testing in small-to-large animal models shows that TaOx NP provides markedly improved vascular contrast compared to iodinated standards, especially under the higher-energy x-ray conditions required for imaging obese patients. Beyond enhancing current CT practice, TaOx NP is ideally suited for emerging photon-counting CT (PCCT) systems, where tantalum’s K-edge enables material-specific imaging and effective suppression of metal artifacts.

This research thrust integrates scalable synthesis, rigorous safety testing (including GLP studies in dog), and advanced imaging evaluation to establish TaOx NPs as a leading candidate for clinical translation. We are exploring TaOx NP potential in cardiovascular imaging—particularly coronary CT angiography (CTA) and imaging of atherosclerosis. Our ongoing work also focuses on tumor and material-specific imaging applications, with the ultimate goal of introducing a safer, more effective class of CT contrast agents into medical practice, unlocking powerful new diagnostic capabilities. With collaborators, we are exploring TaOx NP-enabled medical devices, where nanoparticle incorporation allows longitudinal monitoring of implants in vivo.