Compositions of calcium aluminate cement containing gold and silver nanoparticles for biomaterial applications

Research has been developed in the biomedical engineering field to seek biomaterials that favor bone repair. Studies on orthopedics point out the advantages of using calcium aluminate cement (CAC) to repair bone defects. This is due to its similarity in chemical composition and thermal expansion coefficient of the bones, besides its high viscosity, low heat release, and biocompatibility. The aim of the present study was to investigate the influence of gold (AuNPs) and silver (AgNPs) nanoparticles on the properties of CAC since nanotechnology allows improving the properties and biomaterials, as well as enhancing bone modeling. The samples were prepared from suspensions of homogeneous calcium aluminate cement (CACH) with AuNPs or AgNPs and were evaluated for theoretical density, uniaxial cold crushing strength, flexural stress, microhardness, apparent porosity, pore size distribution, and bioactivity in simulated body fluid (SBF). The suspensions were also evaluated to check their viscosity, injectability, and setting time as functions of solid content. The addition of AuNPs increased the flexural stress, decreased porosity and pore diameter, and increased bioactivity. Injectable pastes were prepared with solid content of 76 wt%, indicating their application potential to bone defects as they are associated with many advantages, for instance, perfect adjustment to the geometry of the bone defect, lesser trauma to the patient, and lower risk of infections. The AuNPs and AgNPs showed influence on the mechanical properties of CACH. The combination of CACH + AuNPs improved its properties, resulting in higher flexural resistance and lower porosity and pore diameter, but AgNP addition showed the worst results in terms of mechanical properties.