Ultrasonic transport of particles into articular cartilage and subchondral bone

Osteoarthritis (OA) is a debilitating musculoskeletal disease without a cure. Delivery of therapeutic compounds is a problem and localized drug therapy could enable new treatment strategies. In this study high-intensity ultrasound was used to deliver micro- and nano-particles (MNPS) into three bovine osteochondral samples: (1) control (C) that was exposed to the particles without sonication, (2) UST-1 that was sonicated prior to immersion in a MNPS and (3) UST-2 that was sonicated in the presence of MNPS. Following treatment samples were cut into 2.9 ± 0.3 mm sections and digital images were obtained by light microscopy. In the sonicated samples (UST-1 and UST-2) MNPS penetrated into articular cartilage and subchondral bone. No MNPS penetration was observed in C. The proposed technique could potentially be used for local drug treatment of OA.