Ultrasound accelerated bone tissue engineering monitored with magnetic resonance microscopy

Tissue engineering has the potential to treat bone loss, but current bone restoration methods, including osteogenesis from mesenchymal stem cells (MSCs), require three to four weeks for bone formation to occur. In this study, we stimulated the formation of engineered bone tissue with low-intensity ultrasound, which has been proven to accelerate bone healing in vivo. One group of engineered bone constructs received ultrasound stimulation 20 minutes per day over a 3-week growth period. We monitored the growth of all the engineered constructs quantitatively and noninvasively using magnetic resonance microscopy (MRM), where the T2 relaxation times of all the constructs were measured, on a weekly basis, using an 11.74 T Bruker spectrometer. Histological and immunocytochemical sections were obtained for all constructs and correlated with the MR results. This study shows that ultrasound can accelerate osteogenesis in vitro for tissue engineered bone, the growth and development of which can be monitored using MRM.