Effects of polypropylene carbonate coating on the degradation and biocompatibility of degradable magnesium alloy AZ31

The use of magnesium alloys as degradable orthopaedic implants is limited by their rapid degradation in vivo and consequent loss of mechanical integrity before sufficient bone healing has occurred. To address this limitation, we coated the surface of AZ31 magnesium alloys with polypropylene carbonate (PPC). The obtained PPC-coated AZ31 showed reduced surface roughness, hardness, and hydrophilicity compared with bare AZ31. The PPC coating also significantly slowed the degradation of AZ31 in a simulated body fluid. The adherence and proliferation of MC3T3 osteoblastic cells cultured on PPC-coated AZ31 samples demonstrated good biocompatibility. The results of the present study indicate that application of a PPC coating may extend the functional period of AZ31 magnesium implants in vivo to allow sufficient time for bone healing and for the stimulation of new bone formation.