Corrosion Behaviour and J774A.1 Macrophage Response to Hyaluronic Acid Functionalization of Electrochemically Reduced Graphene Oxide on Biomedical Grade CoCr

Abstract

Improvements in the lubrication of metal–metal joint prostheses are of great clinical interest in order to minimize the particles released during wear–corrosion processes. In this work, electrochemically reduced graphene oxide (ErGO) on CoCr was functionalized with hyaluronic acid (ErGOHA). Functionalization was carried out by soaking for 24 h in phosphate buffer saline (PBS) solution containing 3 g/L hyaluronic acid (HA). The corrosion performance of CoCrErGO and CoCrErGOHA surfaces was studied by electrochemical impedance spectroscopy (EIS) for 7 days in PBS. Biocompatibility and cytotoxicity were studied in mouse macrophages J774A.1 cell line by the measurement of mitochondrial activity (WST-1 assay) and plasma membrane damage (LDH assay). The inflammatory response was examined through TNF-α and IL-10 cytokines in macrophages culture supernatants, used as indicators of pro-inflammatory and anti-inflammatory responses, respectively. EIS diagrams of CoCrErGOHA revealed two time constants: the first one, attributed to the hydration and diffusion processes of the HA layer adsorbed on ErGO, and the second one, the corrosion resistance of ErGOHA/CoCr interface. Macrophage assays showed better behavior on CoCrErGOHA than CoCr and CoCrErGO surfaces based on their biocompatible, cytotoxic, and inflammatory responses. Comparative analysis of IL-10 showed that functionalization with HA induces higher values of anti-inflammatory cytokine, suggesting an improvement in inflammatory behavior.

Wettability, Corrosion Resistance, and Osteoblast Response to Reduced Graphene Oxide on CoCr Functionalized with Hyaluronic Acid

“…In the circuit of Figure 3 a, a time constant, R coat and CPE2, could be due to the presence of HA on the ErGO surface and attributed to the processes and phenomena that take place through the adsorbed hyaluronic acid, as previously observed in the PBS media of this surface [ 22 ]. The other time constant, R p and CPE1, could be due to a charge transfer process of CoCr passive film/PBS-HA medium interface that takes place through the discontinuities or coating defects of functionalized layers ( Figure 3 a) or directly on the passive film CoCr surface without functionalization ( Figure 3 b).…”

“…Surface modification of materials is a key property in new developments of functional implantable biomaterials used in regenerative medicine and cancer therapies. Therefore, this research aims to generate carbonaceous layers that increase the durability of metal–metal prostheses, while increasing the degree of lubrication at the same time [ 22 ]. In this paper, the main objective is the study of electrochemically reduced graphene oxide on CoCr surfaces functionalized with HA, from the point of view of wettability, corrosion resistance, and osteoblast response.…”