Bioavailability of Strontium Ions from Bioactive Glasses In Vivo: A Micro-PIXE Study of Trace Elements at the Bone Interface

Studying the local release of strontium traces in vivo is of key interest, but calls for highly sensitive techniques besides providing an excellent (micronic) spatial resolution. In this context nuclear microprobes such as the PIXE (Particle-Induced X-ray Emission) technique, appear as powerful tools of investigation. Here, the in vivo behaviour of a Sr-delivering bioactive glass has been investigated through micro-PIXE analyses in connection with histological studies. New bone formation is observed after 6 weeks of implantation in rabbit femoral condyle. Interestingly, Sr traces are detected over a large area at the site of implantation, demonstrating the efficient release of Sr osteo inductive ions from the glass and their diffusion over several ten microns through the tissues. From its inorganic composition and content in traces of interest such as Zn, neo formed bone seems of higher quality for Sr-delivering particles compared to Sr-free particles, evidencing the positive effect of Sr in vivo.