Evaluation of the probability of coating hydroxyapatite, graphene oxide and silk fibroin on titanium implants and its biocompatibility

Abstract

Background and purpose: The aim of this study is to investigate the possibility of hydroxyapatite, graphene oxide and silk fibroin coating on titanium alloy implants and their biocompatibility. Materials and methods: Thirty-five titanium samples were cut to a diameter and length of 10 mm. After grounding samples were sanded with 1200 grade sandpaper in water, and washed with acid, ethanol, and acetone. Hydroxyapatite was coated by electrophoretic deposition on titanium discs and the coating was confirmed by EDX, SEM and XRD tests. Then graphene oxide was grafted on hydroxyapatite by esterification reaction and the resulting products were confirmed by EDX, SEM and XRD spectroscopy. In the next step, silk fibroin was grafted on coated graphene oxide and hydroxyapatite and the resulting product was analyzed and confirmed by EDX, SEM and XRD. The biocompatibility of the composite coating on the implant surface was checked by MTT assay. For data analysis, Kolmogorov-Smirnov test was used to check the normality of the data, one-way analysis of variance and spss version 24 software. Results: SEM images showed uniform coverage of hydroxyapatite particles and graphene oxide sheets with a thickness of 120-130 nm. The morphology of titanium coated with hydroxyapatite-graphene oxide-silk fibroin also has almost uniform parts with porosities. EDX evaluation indicates Ca and P elements in the titanium coated with hydroxyapatite and C and O elements in the sample coated with graphene oxide. In the case of titanium coated with silk fibroin, the amount of C and O elements is still high, and P and Ca elements are still seen in the composition. Evaluation by XRD confirmed the crystalline nature of each stage of the coating. Biocompatibility evaluation did not show a significant difference between the toxicity of uncoated titanium sample and titanium coated with hydroxyapatite-graphene oxide-silk fibroin (P value>0.05). Conclusion: Covering titanium implants with hydroxyapatite by electrophoretic deposition and grafting graphene oxide and silk fibroin on it produces a titanium sample with high biocompatibility.