Biomedical Engineering Reference
In-Depth Information
17.7 (a) SEM micrographs of neat PCL mat. (b) SEM micrograph of
PCL/Ca-deficient nHA 2.0 wt%. (c) SEM micrograph and EDS mappings
of PCL/Ca-deficient nHA 6.4 wt%. (d) SEM micrograph of PCL/Ca-
deficient nHA 24.9 wt%. Reprinted with permission from Elsevier
(Bianco et al., 2009).
rotating collector by electrospinning. At low concentrations the fibres had
no agglomerates and good dispersion was achieved (Jose et al., 2009). The
presence of well-dispersed nHA particles reduced the chain mobility and
hence helped prevent shrinkage to some degree. The glass transition was
affected by the incorporation of nHA into the polymer matrix, which
hinders chain mobility.
Interestingly, the electrospinning technique allows the possibility of
aligning conductive nanoparticles with a high aspect ratio within the
polymeric fibers. Carbo nanofibers (CNFs) can orientate along the axis of
electrospun fibers due to sink flow and high extension of the electrospun jet
(Ago and Tobita, 2002). The CNF alignment depends on the CNF
dispersion in the polymer solution. The idea involves dispersing and aligning
carbon nanostructures in a polymer matrix to form highly ordered
structures. The mechanical properties of PCL/CNF mats, however, were
only slightly affected by CNF introduction (Armentano et al., 2009b).
Ternary nanocomposite scaffolds involving three different materials have
been developed (Mei et al., 2007; Misra et al, 2007). The addition
of MWNTs to the biopolymer makes for a new highly conductive material
due to the 3D electrical conducting network. The results showed that
combining two different nanostructures (e.g. MWNT/nHA or MWNT/
Bioglass
â
) led to multifunctional biomaterials with tailored bioactivity,
structural and mechanical integrity as well as electrical conductivity of the
porous scaffolds.
