Cobalt Chromium Molybdenum Surface Modifications Alter the Osteogenic Differentiation Potential of Human Mesenchymal Stem Cells

Abstract

Surface roughness on orthopedic implant materials has been shown to be highly influential on the behavior of osteogenic cells. Mesenchymal stem and progenitor cells (MSPCs) migrate to the interface, adhere, proliferate, and differentiate into osteoblasts, which subsequently form bone matrix. Modifications of the implant surfaces should accelerate this process and improve biocompatibility. In this study, five surface topographies on cobalt chromium molybdenum (CoCrMo) were engineered to examine the influence on MSPCs. Scanning electron microscopy revealed significant differences in the morphology of untreated CoCrMo discs in comparison with CoCrMo with a titanium nitride (TiN) coating, polished and porous coated CoCrMo surfaces, and CoCrMo with a pure titanium (cpTi) coating. Elemental analysis was performed using energy-dispersive X-ray spectroscopy (EDX). Human primary MSPCs were expanded from tissue samples of spongiosa bone and characterized according to the criteria of the International Society for Cellular Therapy. The characteristic phenotype of MSPC was confirmed by flow cytometry and multilineage differentiation. Alcaline phosphatase and osteopontin expression increased significantly in all groups about 5-fold and 10-fold, respectively, in comparison to the undifferentiated controls. The porous coated surface showed a reduced expression of osteogenic markers. Due to the osteogenic differentiation, the expression of integrin α5β1, which is particularly important for cell-material contact, increased 4–7-fold. In the dynamic process of bone biology, MSPCs cultured and differentiated on cpTi, showed significant upregulation of IL6 and leptin.

Graphene and its Derivatives for Bone Tissue Engineering: In Vitro and In Vivo Evaluation of Graphene-Based Scaffolds, Membranes and Coatings

“…The cobalt-chromium-molybdenum-based alloy (CoCrMo) was also an important candidate for orthopedic implants due to its excellent corrosion and wear resistance. Nonetheless, their biocompatibility and bioactivity were unsatisfactory ( Lohberger et al, 2020 ). Although many attempts have been made to improve their biocompatibility, none of the efforts are effective ( Poh et al, 2011 ; Logan et al, 2015 ; Sahasrabudhe et al, 2021 ).…”

Differences in In Vitro Bacterial Adherence between Ti6Al4V and CoCrMo Alloys

“…Nevertheless, it seems reasonable that higher biocompatibility allows the growth of bone cells on its surface more quickly, protecting the surface from colonisation by bacterial pathogens. CoCrMo biocompatibility and osseointegration can be improved using different strategies that modify the surface [ 31 , 32 ]. This metal ion release could affect microbial metabolism and play an important role in the differences observed in adherence [ 33 ].…”

Effect of Cobalt–Chromium–Molybdenum Implant Surface Modifications on Biofilm Development of S. aureus and S. epidermidis

“…The resulting coating had a porosity of 30 ± 10%, an average roughness of 50 ± 15 µm, a tensile strength of ≥22 MPa and a shear strength of ≥20 MPa. cpTi covered materials show an improved osteogenic differentiation potential ( Lohberger et al, 2020a ), since the given porous upper layer in combination with the increase in surface energy offers the bone cells an optimal structure for adhesion ( Geetha et al, 2009 ). Tricalcium phosphate coating (TCP, Bonit ® ) led to a deposited layer of 20 ± 10 µm thickness and to a tensile strength of ≥15 MPa ( ISO 13779-2, 2018 ).…”