Nanoparticle Lubricant and Imaging Agent: Preventing and Assessing Cartilage Tissue Damage.

Introducing additives to industrial lubricants reduces friction and wear between articulating metal surfaces by mechanistically impeding interfacial adhesion, heat dissipation, and abrasion. With this inspiration, we report the synthesis and use of tantalum oxide (Ta2O5) nanoparticles as a nanolubricant and tribosupplement (i.e., tribology-augmenting agent) for articular cartilage. Further, as tantalum oxide absorbs X-rays, the nanolubricant is also a contrast-agent for computed tomography (CT). These dual purpose nanoparticles, decorated with a short poly (ethylene glycol) and cationic trimethylammonium silane coating, suspend in aqueous fluid to form a CT active nanolubricant. In an ex vivo cartilage-on-cartilage model, the nanolubricant outperforms the clinical standard, Synvisc-One, as a viscosupplement during high load, low velocity sliding associated with low Hersey numbers and high static friction. Differential diffusion of the nanolubricants into healthy and degraded cartilage demonstrates the diagnostic capability of the nanolubricant to also distinguish disease state by μCT.