In vivo study of the effect of composition and implantation site on scaffold degradation rate

Tissue engineering devices stabilize wounds, then degrade. However, published degradation rates often conflict. Incorporating monitoring functionality into devices allows real-time assessment of degradation and failure, but requires contrast agents, as polymer devices are invisible to most medical imaging modalities. Therefore, computed tomography (CT)-visible composite scaffolds were created from 5-20 wt% tantalum oxide (TaOx) nanoparticles in polymers with distinct degradation profiles: polycaprolactone, poly(lactide-co-glycolide) (PLGA) 85:15 and PLGA 50:50, representing slow, medium and fast degrading materials. Scaffolds, mimicking biomedical devices, were implanted into mice intramuscularly or intraperitoneally, and monitored via CT over 20 weeks. Scaffold degradation profile was dictated by polymer matrix, regardless of nanoparticle addition. Foreign body response was dependent on implant site and in mid-degrading composites degradation rates transitioned from linear degradation intramuscularly to exponential degradation intraperitoneally. Nanoparticle excretion via liver and spleen lagged polymer degradation. Overall, real time tracking of device behavior was demonstrated, advancing an era of personalized medicine. Tissue engineering devices degrade over time, but monitoring their degradation requires imaging contrast agents. Here, the authors developed computed tomography-visible TaOx-polymer composite scaffolds that enabled real-time in vivo tracking, showing that degradation depended on the polymer matrix and implantation site, supporting personalized medicine.