In Vitro Biodegradation and In Vivo Biocompatibility of Forsterite Bio-Ceramics: Effects of Strontium Substitution.

The present study investigates the potential use of forsterite as an orthopedic biomaterial along with the role of strontium oxide (SrO) as a dopant. The in vitro degradation behavior was measured as a function of immersion time in simulated body fluid (SBF) for up to 8 weeks and was analyzed by micro computed tomography (µ-CT) and scanning electron microscopy (SEM). All the doped samples showed higher degradation than pure sample. The in vitro cytocompatibility study showed good cytocompatibility and proliferation of MC3T3-E1 cells on Sr-doped MgS samples. The in vivo experiments were carried out by implanting the ceramics in a rabbit femur for 30 and 90 days. The 3D µ-CT and SEM images of 2 and 3 wt % Sr-doped MgS showed increased bone regeneration around the implant materials compared with pure and 1 wt % Sr-doped MgS, which was further confirmed by quantitative oxytetracycline labeling. The histological examination of three major organs of heart, kidney, and liver confirmed that the degradation product of the MgS ceramics, with or without doping, had no toxicological side effects. These results indicate that Sr-doped MgS bioceramics exhibit enhanced degradability with the potential to be used for temporary bone regeneration.

In Vivo Biocompatibility of Zinc-Doped Magnesium Silicate Bio-Ceramics.

Magnesium-based bioceramics have emerged as a new class of biodegradable bone replacement material due to their higher degradation and good cytocompatibility. In the current research, we have prepared pure and zinc-doped magnesium silicate (MgS) bioceramics by solid state method and evaluated the in vitro degradability and in vivo biocompatibility. In vitro degradation of the MgS bioceramics was assessed in simulated body fluid (SBF) which showed enhanced degradability for 0.5 wt % Zn doped MgS samples. The in vivo biocompatibility was evaluated by implanting the samples in rabbit femur critical size defect. All the MgS samples were well-integrated at the host tissue site as evident in 90 day radiographic images and micro computed tomography (µ-CT). Oxytetracycline labeling indicated that 0.5 wt % Zn doped MgS samples had better bone regeneration after 90 days of implantation as compared to pure and 0.25 wt % Zn-doped samples. Any systemic and organ toxicity was negated by normal vital organ (heart, kidney, and liver) histology at 90 days.