Background The restoration of large cancellous bone defects in weight-bearing sites is a major problem to be solved in clinical practice. Currently, calcium phosphate (Ca-P) bioactive coatings combined with porous magnesium is expected to solve this problem, but the evaluation of mechanical properties and biocompatibility is lacking.
Objective To evaluate the mechanical properties and biocompatibility of the porous magnesium scaffolds with Ca-P coating.
Methods The porous magnesium scaffold was manufactured by selective laser melting 3D printing and Ca-P bioactive component was successfully coated on the surface of scaffolds by chemical transformation while the scaffold without coating was the control group. The morphology and composition of the coating were characterized by scanning electron microscopy (Scanning electron microscope, SEM) and energy dispersive spectroscopy (Energy-dispersive X-ray spectrometry, EDS). The compression mechanics experiment was conducted and the stress-strain curve was drawn to calculate the yield strength and elastic modulus of the scaffold. The biocompatibility of porous magnesium scaffolds was tested by CCK-8 assay, live and dead staining and cell adhesion experiment.
Results Porous magnesium scaffolds with Ca-P coating had been successfully manufactured. The results of SEM and EDS showed that the magnesium particles in porous magnesium scaffolds presented a fused sheet and the Ca-P coating was composed of petal-like grains stacked with each other in a certain orientation, integrated with magnesium matrix closely. Mechanical tests showed that the compressive strength of porous magnesium scaffolds coated with Ca-P was higher than that of non-coated scaffolds (35.3 ± 0.7 Mpa vs 31 ± 1.0 Mpa, P=0.0029, n=3), so as Young's modulus (656 ± 8.7 Mpa vs 623 ± 7.0 Mpa, P=0.0076, n=3). The biocompatibility experiments showed that compared with the control group, Ca-P coated scaffolds significantly promoted cell proliferation (P<0.05), while uncoated scaffolds had significant inhibitory effect (P<0.05).
Conclusion The Ca-P coated porous magnesium scaffolds are featured with strong mechanical properties and good biocompatibility, which can be applied for the treatment of cancellous bone defects in weight-bearing sites.
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