In vitro biodegradability and biocompatibility of porous Mg-Zn scaffolds coated with nano hydroxyapatite via pulse electrodeposition

The biodegradability and biocompatibility of porous Mg-2Zn (mass fraction, %) scaffolds coated with nano hydroxyapatite (HAP) were investigated. The nano HAP coating on Mg-2Zn scaffolds was prepared by the pulse electrodeposition method. The as-deposited scaffolds were then post-treated with alkaline solution to improve the biodegradation behavior and biocompatibility for implant applications. The microstructure and composition of scaffold and nano HAP coating, as well as their degradation and cytotoxicity behavior in simulated body fluid (SBF) were investigated. The post-treated coating is composed of needle-like HAP with the diameter less than 100 nm developed almost perpendicularly to the substrate, which exhibits a similar composition to natural bone. It is found that the products of immersion in SBF are identified to be HAP, (Ca, Mg)3(PO4)2 and Mg(OH)2. The bioactivity, biocompatibility and cell viabilities for the as-coated and post-treated scaffold extracts are higher than those for the uncoated scaffold. MG63 cells are found to adhere and proliferate on the surface of the as-coated and post-treated scaffolds, making it a promising choice for medical application. The results show that the pulse electrodeposition of nano HAP coating and alkaline treatment is a useful approach to improve the biodegradability and bioactivity of porous Mg-Zn scaffolds.