Incorporation of Gadolinium Oxide and Gadolinium Oxysulfide Microspheres: MRI/CT Monitoring and Promotion of Osteogenic/Chondrogenic Differentiation for Bone Implants

Abstract The current biodegradable polymer materials, as orthopedic implants, can not be traced timely by using the existing medical imaging techniques due to low density and lack of relaxed hydrogen proton ability. Considering the paramagnetism of gadolinium and the particularity of micro/nano materials, we synthesized inorganic gadolinium oxide and gadolinium oxysulfide microspheres with regular morphology and uniform size without doped rare earth. After incorporation into biodegradable polymer of poly(lactic‐co‐glycolic acid), their effects on signals of MRI, CT and osteogenic/chondrogenic differentiation were investigated to acquisition of multifunctional micro/nano composites for bone implants. At the studied concentrations, gadolinium oxide microspheres showed higher signal than gadolinium oxysulfide microspheres on T₁‐weighted imaging. Both of them were of fine biocompatibility and did not show their negative effect on adhesion and proliferation in the concentration of 0.4% (w/w, Gd/PLGA). Meanwhile, the osteogenic/chondrogenic differentiation of MC3T3‐E1 preosteoblasts, including ALP activity, calcium deposition and expression of Runx2, OPN, OCN, COL I and COL II in mRNA and protain, were stimulated at different level, which indicated that moderate use the inorganic gadolinium oxide and gadolinium oxysulfide microspheres could realize the function of tracing the polymer bone implants by MRI/CT and inducing the osteogenic/chondrogenic differentiation simultaneously.