  Magnesium and its alloys have aroused tremendous interests because of their
promising mechanical properties and biocompatibility. However, their
excessively fast corrosion rate hinders the development of Mg alloys in the
biomedical fields. Inspired by conventional ion implantation, a less-toxic
functional group (hydroxyl) is used as the ion source to bombard the ZK60 Mg
alloy surface to form a functionalized oxide layer. This functionalized oxide
layer significantly facilitates the corrosion resistance of the ZK60 Mg alloy
substrate and the proliferation of MC3T3-E1 cells, which is confirmed by
electrochemical, immersion, and in vitro cytocompatibility tests. In comparison
with results of ZK60 alloy implanted with carboxyl ions in our previous work,
it is concluded that hydroxyl-treated alloys exhibit slightly higher corrosion
rate while better biocompatibility. In summary, less-toxic functional ion
implantation can be an effective strategy for inhibiting corrosion of Mg alloy
implants and promoting their biocompatibility.
