In-situ grown Ag on magnetic halloysite nanotubes in scaffolds: Antibacterial, biocompatibility and mechanical properties

A novel design of antibacterial and magnetic halloysite nanotubes loaded with Ag and Fe 3 O 4 was reported. In detail, magnetic nanoparticles (Fe 3 O 4 ) were immobilized on the surface of halloysite nanotubes (HNTs) via electrostatic adsorption (termed as HNTs/Fe 3 O 4 ). The magnetic HNTs/Fe 3 O 4 was then modified by polydopamine to in-situ grow Ag nanoparticles by a redox reaction , forming a composite nanostructure of HNTs/Fe 3 O 4 @Ag. The HNTs/Fe 3 O 4 @Ag was incorporated into poly- l -lactic acid (PLLA) scaffold fabricated via selective laser sintering , with the intent to endow the scaffold with robust antibacterial function and favorable cell activity. The results showed that the released Ag + from the scaffold significantly against E. coli activity, with bacterial inhibition rate above 99%. Moreover, ion release behavior showed a scaffold enable to sustain release Ag + over 28 days. Furthermore, Fe 3 O 4 nanoparticles constructed magnetic microenvironment greatly enhanced cell activity and promoted cell proliferation . In addition, tensile strength of the scaffold increased by 52.9% compared with PLLA scaffold. These positive results suggested that the HNTs/Fe 3 O 4 @Ag nanostructure possessed potential in facilitating bone repair.