Disperse magnetic sources constructed with functionalized Fe3O4 nanoparticles in poly-l-lactic acid scaffolds

Abstract

Fe3O4 nanoparticles were widely applied as magnetic sources in scaffolds to stimulate bone regeneration. In this study, Fe3O4 nanoparticles were successfully functionalized by oleic acid to circumvent the aggregate issue of the nanoparticles in poly-l-lactic acid (PLLA) bone scaffolds fabricated via selective laser sintering. On the one hand, carboxylic acid groups of oleic acid may interact with the hydroxyl groups of Fe3O4 nanoparticles in case of aqueous medium, contributing to the surface functionalization of the nanoparticles. On the other hand, hydrocarbon chains of oleic acid were oriented toward the PLLA matrix and mutually exclusive, facilitating the dispersion of the nanoparticles in PLLA scaffolds. As a result, the dispersion of functionalized Fe3O4 nanoparticles in scaffold was significantly better than that of non-functionalized nanoparticles. The magnetic scaffolds with uniformly dispersed nanoparticles (12 wt%) presented increased compressive strength and modulus by 95% and 68%, respectively, owning to the rigid enhancement effect of nanoparticles. Meanwhile, they exhibited good capabilities of cell adhesion, proliferation and differentiation, due to the magnetic stimulation for cells produced by uniformly dispersed magnetic sources. All these positive results indicated that the magnetic scaffolds showed great potential in the application of bone regeneration.