Biomedical Engineering Reference
In-Depth Information
FIGURE 10.3
Schematic diagram of PLLA/MWCNTs/HA membrane
fabrication process.
and PLLA particles were added to the suspension until a weight ratio of MWCNTs/HA to PLLA of 1:9
was achieved. The suspension was kept in a 50°C oven for 12 h to get a well-mixed solution. The solution
was then electrospun at the same parameters as those for PLLA and PLLA/HA nanofibers.
10.4.3
Characterization of PLLA/MWCNTs/HA Composite Nanofibers
The diameters of electrospun PLLA/MWCNTs/HA fibers were about 1 μm, and the incorporation
of MWCNTs/HA nanoparticles resulted in fibers more irregular in diameter and more beaded in
morphology than pure PLLA fibers. Energy dispersive X-ray spectroscopy (EDX) analysis shows
the presence of P and Ca elements distributed uniformly in the fibrous membrane. The presence of
MWCNTs was confirmed by Raman spectrum (
Figure 10.4
).
The results of the
in-vitro
degradation tests (phosphate buffer solution (PBS, pH 7.4), 37 C) dem-
onstrated the incorporation of HA or MWCNTs/HA slowed down the rate of mass loss, especially
showing the lag phase in the early stage (
Figure 10.5
). The presence of alkaline HA particles could
neutralize the acidic degradation products of hydrolyzed PLLA, which decreased the acid autocatalyt-
ical degradation rate of PLLA. It was indicated that the incorporation of HA or MWCNTs/HA could
prevent PLLA membranes from rapid decomposition and a rapid decrease of pH in the surrounding
environment during the degradation.
