Tantalum Oxide Nanoparticles for the Imaging of Articular Cartilage Using X‐Ray Computed Tomography: Visualization of Ex Vivo/In Vivo Murine Tibia and Ex Vivo Human Index Finger Cartilage

Abstract

The synthesis and characterization of tantalum oxide (Ta2O5) nanoparticles (NPs) as new X‐ray contrast media for microcomputed tomography (μCT) imaging of articular cartilage are reported. NPs, approximately 5–10 nm in size, and possessing distinct surface charges, were synthesized using phosphonate (neutral), ammonium (cationic), and carboxylate (anionic) ligands as end functional groups. Assessment of a cartilage defect in a human cadaver distal metacarpophalangeal (MCP) joint with the ammonium nanoparticles showed good visualization of damage and preferential uptake in areas surrounding the defect. Finally, an optimized nontoxic cationic NP contrast agent was evaluated in an in vivo murine model and the cartilage was imaged. These nanoparticles represent a new type of contrast agent for imaging articular cartilage, and the results demonstrate the importance of surface charge in the design of nanoparticulate agents for targeting the surface or interior zones of articular cartilage.

Functions and applications of metallic and metallic oxide nanoparticles in orthopedic implants and scaffolds

“…The positively charged tantalum oxide nanoparticles demonstrated an enhanced affinity for articular cartilage because of the coulombic attraction. 150 In addition, nontoxic nanocarriers can be used widely in both chemotherapy through drug delivery, and radiotherapy through acting as radiosensitizers. 151 Chen et al 151 Tantalum nanoparticles can also improve the mechanical properties of bone scaffolds.…”

“…Many inorganic nanoparticles have been tested in medical imaging. Tantalum oxide nanoparticles are chemically inert and biocompatible, and have excellent radiopacity, which makes them suitable for use as X‐ray and CT contrast agents 148‐150 . Freedman et al 150 used tantalum oxide nanoparticles as a CT contrast agent for successful imaging of human articular cartilage.…”

“…Tantalum oxide nanoparticles are chemically inert and biocompatible, and have excellent radiopacity, which makes them suitable for use as X‐ray and CT contrast agents 148‐150 . Freedman et al 150 used tantalum oxide nanoparticles as a CT contrast agent for successful imaging of human articular cartilage. The positively charged tantalum oxide nanoparticles demonstrated an enhanced affinity for articular cartilage because of the coulombic attraction 150 .…”

“…Freedman et al 150 used tantalum oxide nanoparticles as a CT contrast agent for successful imaging of human articular cartilage. The positively charged tantalum oxide nanoparticles demonstrated an enhanced affinity for articular cartilage because of the coulombic attraction 150 . In addition, nontoxic nanocarriers can be used widely in both chemotherapy through drug delivery, and radiotherapy through acting as radiosensitizers 151 .…”

An Innovative Agent-Based Cellular Automata Framework for Simulating Articular Cartilage Biomechanics

“…As constituents of the articular cartilage are intermixed at a molecular level [5], MRI and CT scan techniques cannot directly distinguish components of the tissue. Advanced MRI techniques can assess composition of cartilage indirectly [121,122] using contrast agents such as Hexabrix [12], sodium iodide [123], tantalum oxide nanoparticles [124] and gadopentetate [125]. For example, delayed gadolinium enhanced MRI of cartilage (dGEMRIC) uses fixed charge density (FCD) within the tissue to measure proteoglycan content quantitatively.…”