Influence of graphene oxide and carbon nanotubes on physicochemical properties of bone cements

The influences of graphene oxide (GO) and carboxyl functionalized multi-wall carbon nanotubes (f-MWCNTs) on mechanical and biological performances bone cements used as the bone substitute are investigated. The bioresorbable and bioceramics were prepared of calcium sulfate diydrate, tetra calcium phosphate and dicalcium phosphate dihydrate is fabricated by a solid-state high temperature process. Then the bioceramic is mixed with carboxymethyl cellulose, gelatin and nanocarbons. The addition of 0.5 wt% f-MWCNT and 1 wt% GO is found to increase the compressive strength of the resultant nanocomposite by %50 and %55, respectively, in comparison to that of the bare bone cement. 1 wt% GO incorporated bone substitutes had the optimum mechanical properties which had compressive modulus and compressive strength of 1.9 +/- 0.3 and 35.8 +/- 0.5 MPa, respectively. Moreover, GO is found to be more effective than f-MWCNT in stabilizing pH. The degradation rate of the bone cement is stabilized through GO incorporation but increased by incorporating f-MWCNT. Bone substitutes up to 1 wt% nanocarbons exhibit biocompatibility and MC3T3-E1 pre-osteoblasts were mineralized after 14 days of cell culture. The results demonstrate that the physicochemical properties of the nanocomposites are significantly affected by the concentration and surface properties of nanocarbons.