Biodegradable microcarriers as cell delivery vehicle for in vivo transplantation and magnetic resonance monitoring.

Microcarrier culture systems offer an attractive method for cell amplification and as delivery vehicle. At the same time, super paramagnetic iron oxide (SPIO) nanoparticles represent a unique in vivo tracking system, already approved for clinical use. In our study, we tested the combination of clinically approved microcarriers and SPIO nanoparticles for cell-construct delivery and subsequent tracking after implantation. In order to mimic better a clinical setting, biodegradable macroporous microcarriers were employed as an alternative approach to expand human primary chondrocytes in a dynamic culture system for subsequent direct transplantation. In addition, cellseeded microcarriers were labeled with SPIO nanoparticles to evaluate the benefits of cell-constructs tracking with magnetic resonance. In vivo subcutaneous implants were monitored for up to 3 weeks and orthotopic implantation was simulated and monitored in ex vivo osteochondral defects.