In vitro and in vivo degradation and mechanical properties of ZEK100 magnesium alloy coated with alginate, chitosan and mechano-growth factor.

The biocompatibility, ultimate loading capacity and biodegradability of magnesium alloy make it an ideal candidate in biomedical fields. Fabrications of multilayered coatings carrying sodium alginate (ALG), chitosan (CHI) and mechano-growth factor (MGF) on fluoride-pretreated ZEK100 magnesium alloy have been obtained via layer by layer (LBL) to reduce the degradation rate of magnesium alloy in this study. The modified surfaces of ZEK100 substrates were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) and CARE EUT-1020 tester. Results reveal that multilayer-coated magnesium alloy can be successfully obtained with smooth surface morphology, and the mechanical properties of coated samples are almost the same as those of uncoated samples. However, the fatigue life of coated ZEK100 is slightly larger than that of uncoated samples after 1 day of immersion. By comparing the degradation of uncoated and multilayer-coated ZEK100 samples in vitro and in vivo, respectively, it is found that the degradation rate of ZEK100 samples can be inhibited by LBL modification on the surface of the sample; and the corrosion rate in vivo is lower than that in vitro, which help solve the rapid degradation problem of magnesium alloy. In terms of the visible symptom of tissues in the left femur medullary cavity and material responses on the surface, multilayer-coated ZEK100 magnesium alloy has a good biocompatibility. These results indicate that multilayer-coated ZEK100 may be a promising material for bone tissue repair.