Effects of polylactic acid coating on properties of porous Zn scaffolds as degradable materials

In recent years, porous Zn-based scaffolds have been proposed as promising candidates for ideal bone tissue engineering scaffolds to treat large bone defects. However, the degradation rates of Zn-based implants are still relatively slow for orthopedic applications. Moreover, the released excessive Zn2+ will lead to cytotoxicity. In this work, porous Zn scaffolds modified with polylactic acid (PLA) coating (PLA/Zn) were fabricated by ultrasonic infiltration of porous Zn scaffolds in different concentrations of PLA-trichloromethane solutions and subsequent centrifugal treatment. The effect of PLA coating on mechanical properties, in vitro degradation behaviors, antibacterial properties, and cytotoxicity of the scaffolds were investigated. The results show that the PLA coating is helpful to improve the mechanical strength of the scaffolds. In addition, the PLA coating can accelerate degradation of porous Zn scaffolds, and the degradation behavior of the porous scaffolds can be easily regulated by controlling the PLA coating thickness. Antibacterial tests suggest that the porous Zn scaffolds modified with PLA coating have good antibacterial ability to Escherichia coli. Cytotoxicity tests indicate that the 10% extracts of the porous Zn scaffolds modified with PLA coating exhibit excellent cell viability on MC3T3-E1 cells and the specimens have acceptable biocompatibility. The prepared PLA/Zn scaffolds have great potential for application in the field of bone tissue engineering scaffolds.