New functionalities of a bone cement by adding mechanochemically synthesized magnetic nanoparticles

Abstract

New formulations of calcium phosphate cements (CPCs) with magnetic properties have been developed. The CPC matrix was prepared from an equimolar mixture of tetracalcium phosphate (TTCP) and anhydrous calcium hydrogen phosphate (DCPA), using Na2HPO4 solution as liquid phase. Naked and functionalized iron oxides nanoparticles (IONPs), were incorporated into the CPC solid phase and the effect of the different contents of IONPs on the initial and final setting times of the CPCs was investigated. Moreover, magnetic properties, antibacterial activity and magnetic hyperthermia response of these systems were evaluated. The results showed a clear influence of the IONPs in the setting process, with low conversion of hydroxyapatite (HA), especially for contents greater than 10 wt%. Magnetization values of 5.6 and 11.4 emu/g at the maximum applied field (13 kOe) for CPC with 10 and 20 wt% of IONPs respectively, were obtained. Magnetic hyperthermia of CPC with 10 wt% of IONPs showed a specific power absorption (SPA) of 0.22 (W/g). Similar values of SPA were obtained for cements with functionalized IONPs. Also, CPC with 10 wt% of functionalized IONPs with usnic acid showed antibacterial activity against L. inoccua. These data are promising, considering that the concentration of IONPs in the cement is only equivalent to 10 wt% of the material.