Mg and its alloys are biodegradable and mechanically strong materials, which can be used for an orthopedic implant and device applications, but corrosion rate of these alloys is high. In this research, the nanocomposite coatings of chitosan (CS)/graphene oxide (GO) were fabricated to improve the corrosion resistance of the Mg–2 wt% Zn scaffold. The contents of the GO nanosheets and the pulse electrodeposition process parameters, including peak current density (CD) and duty cycle (DC), will also be investigated. The Mg–2 wt% Zn as a substrate of the scaffold was prepared using a powder metallurgy process. The influence of the porosity was studied on the microstructure fabricated scaffolds. The coating microstructures and morphologies were investigated by Raman spectroscopy, x-ray diffraction, thermogravimetric analysis, and SEM. The atomic force microscopy was performed to study the thickness of the nanocomposite coatings. The zeta potential measurement was conducted for the dispersion of the GO nanosheets in the CS matrix. The obtained results showed that the optimum conditions to fabricate a uniform CS/GO coating on the scaffolds were 2 wt% GO, CD = 20 mA cm−2, and DC = 0.5. The pH, time and temperature for the fabrication of the coatings were conducted at 5, 20 min, and 37 °C, respectively. Additionally, the potentiodynamic polarization measurement in simulated body fluid indicated that the CS/GO coatings could provide effective protection of the scaffolds against corrosion. Additionally, the optimum sample obtained from the aspect of the corrosion behavior demonstrated adequate biocompatibility with proper adhesion of mouse fibroblast cells (L929) on the CS–2 wt% GO coating.

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In the present study, optimal conditions for the fabrication of chitosan (CS)/graphene oxide (GO) nanocomposite coatings were evaluated by the pulse electrodeposition process (PED) on Mg–2wt%Zn scaffolds. The size distribution of CS, GO, and nanocomposite coatings were evaluated using dynamic light scattering (DLS). The coatings microstructure and morphologies were investigated by the Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV- visible), Raman spectroscopy, thermogravimetric analysis (TGA), derivative thermal gravimetric (DTG), differential thermal analysis (DTA), and scanning electron microscopy (SEM). Taguchi statistical method was used to optimize the effect of PED parameters, including peak current density (CD) and duty cycle (DC) as well as GO nanosheets content (1,2, and 3wt%). Results showed that optimal coatings were produced under the conditions of 2 wt% GO, CD = 20 mA/cm 2, DC = 0.5 and pH = 5. The process's time, temperature, and frequency were 20 min, 37oC, and 1000 Hz. The biocompatibility of coatings was assessed by in vitro test. The results of cell viability and adhesion of MG63 cells on optimal coating are promising for application in bone tissue engineering.

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