Influence of low modulus Co-Zr alloys surface modification on protein adsorption and MC3T3-E1, NIH3T3 and RAW264.7 cell behaviour

Abstract

Three types of Co-xZr (x = 5, 7.5, and 10 wt.%) were treated with hydroxyapatite (HA) and used as an object to investigate the effect of HA coating on the surface and biocompatibility of Co-xZr alloys. And the protein adsorption and the subsequent biological behaviour of osteoblast, fibroblast and macrophages were also investigated. The surface microstructure and wettability were assessed by scanning electron microscopy (SEM) and static angle profilometer. To evaluate the biocompatibility of Co-xZr and Co-xZr-HA, we quantified plasma proteins adsorption by bicinchoninic acid assay (BCA), cytotoxicity and cell proliferation by cell counting kit-8 (CCK-8) and scanning electron microscopy (SEM). The results indicated that Co-xZr-HA alloy surfaces were more hydrophilic and had higher affinity to plasma proteins. Higher protein concentrations were found adsorbed onto Co-7.5Zr-HA and Co-10Zr-HA alloys. Cytotoxicity analysis indicated that HA coating improved the biocompatibility of Co-xZr alloys. Furthermore, the comparable results of co-incubation of Co-xZr-HA alloys with cells reveal cellular attachments to HA surfaces. HA was successfully formed on Co-xZr alloys and modified the surface structure and biocompatibility of the alloys. Co-10Zr-HA and Co-7.5Zr-HA had the most favourable properties and cytocompatibility, and therefore can be potentially used for dental implants.