Remotely actuated shape memory effect of electrospun composite nanofibers.

One class of biodegradable polymer composite nanofibers was fabricated with an electrospinning process using chemically cross-linked poly(ε-caprolactone) (c-PCL) as the matrix and multiwalled carbon nanotubes (MWNTs) as the reinforced filler coated with Fe3O4 nanoparticles as a magnetism responsive source. The composite fibers showed an excellent shape memory effect, triggered both by hot water and by an alternating magnetic field. The heat in the PCL matrix generated from magnetic nanoparticles via hysteresis loss in the magnetic field was also determined quantitatively. The Fe3O4-loaded MWNT composite nanoparticles (Fe3O4@CD-M) were synthesized through two steps: (1) the raw MWNTs were firstly functionalized by grafting maleic anhydride (MA) on their surface through a free radical reaction and later covalently modified by β-cyclodextrin (β-CD) through an esterification reaction; (2) Fe3O4@CD-M composite nanoparticles were prepared by chemical co-precipitation of Fe2+ and Fe3+ ions on the surface of the β-CD functionalized MWNTs with an electrostatic self-assembly approach using β-CD as the depositional locus. Alamar blue assay was also performed from culturing osteoblast populations to evaluate the cytotoxicity. The result showed that the electrospun composite fibers possessed good biocompatibility and could be applied in biomedical fields.