Biomedical Engineering Reference
In-Depth Information
(A)
(B)
7.50
7.45
7.40
7.35
7.30
PLLA
PLLA/HA
PLLA/MWNT s/HA
PLLA
PLLA/HA
PLLA/MWNT s/HA
10
8
6
7.25
4
7.20
7.15
2
7.10
0
0
1
2
3
4
5
6
7
8
0
1
4
Degradation time(weeks)
2
3
5
6
7
8
Degradation time(weeks)
FIGURE 10.5
Characteristics of three kinds of membranes during
in-vitro
degradation: (A) and (B) represent the
changes of mass loss and pH, respectively.
The density of PDLCs on PLLA/MWCNTs/HA membranes was the highest among those of
the three membranes. The cells spread over the membrane fibers, linked with fibers by cytoplas-
mic extensions. PDLCs were more actively extended on the PLLA/MWCNTs/HA membrane than
on the PLLA and PLLA/HA membranes during the same culture time. More granulates, which was
an implication of mineralization, were observed on the surface of attached cells on PLLA/HA and
PLLA/MWCNTs/HA membranes (
Figure 10.6
).
By MTT assay (
Figure 10.7
), the PDLC number was similar at 1 day for the three tests and con-
trol group, while the most active proliferation was observed on the PLLA/MWCNTs/HA composite
membrane, which was almost 3 times that of the initial seeding cells and 30% larger than that of
the PLLA/HA membrane or control group for 7 days of culturing (
P
0.05). However, the PLLA/
MWCNTs/HA membrane prohibited the adhesion and proliferation of GECs compared with the con-
trol group.
The results suggested that the PLLA/MWCNTs/HA membrane would selectively increase the
adhesion of osteoblast cells and decrease the adhesion of osteoblast competitive cell lines, which was
a valuable feature for GTR application.
10.4.5
In-Vivo Implantation of PLLA/MWCNTs/HA Membranes
PDLCs were cultured in an osteogenic differentiation medium for 7 days and then seeded into PLLA/
MWCNTs/HA membranes and cultured in an osteogenic differentiation medium for 48 h. Under gen-
eral anesthesia, cell/membrane composites were implanted into one side of leg muscle pouches of
10 immunodeficient mice. After 4 weeks, all mice were sacrificed. The block sections were rinsed in
sterile saline and fixed in 10% buffered formalin and prepared for paraffin sections (of 5 μm) to con-
duct histological examinations.
It was observed that residual electrospun fibers could be clearly identified; no obvious
inflammation was found in the implant areas. As shown in
Figure 10.8
, bone-like tissues were
