Development of graphene oxide/silver nanocomposite coating on NiTi alloy for biomedical applications

Abstract

The study aimed to evaluate the surface, mechanical, and biological properties of graphene oxide/silver nanocomposite (GO/Ag) coated NiTi alloy. Substrates were coated using the electrophoretic deposition at 30 V for 1, 5, and 10 min, and were characterized by scanning electron microscope, Raman spectroscopy, energy dispersive spectroscopy, surface profilometer, and atomic fluoroscope force microscopy (AFM). Hardness, modulus of elasticity, and friction were done and surface adhesion was measured from AFM. Biocompatibility testing was done on human gingival fibroblasts using 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed using SPSS 16; One-way ANOVA with post hoc Scheffe Test (P = 0.05). The coatings were confirmed from Raman spectroscopy (D bands at ∼1300 cm−1, G bands at ∼1600 cm−1 and ratio of D and G band was 0.83). The thickness of the coatings ranged from 0.34 to 1.12 µm for the GO and 0.45 to 1.33 µm for the GO/Ag coatings. Increasing coating time increased the roughness, thickness, and Young’s modulus but decreased the hardness. The friction of the coated alloy was lower than the uncoated alloy. Uncoated NiTi group showed less viable cells than the coated and control group. 10 min coatings showed higher viable cells than 1 and 5 min. The GO and the GO/Ag-coated NiTi alloys can be used for biomedical applications.