Biomedical Engineering Reference
In-Depth Information
turn into osteoarthritis. Autologous chondrocytes implantation was
first published by Brittberg
et al.
17
Recently, articular cartilage
repairhasbeengivenmuchintentioninorthopedictissueengineer-
ing. Usually scaffolds are designed as a highly porous 3D structure
to allow cells to accommodate and grow inside, as well as organize
cells into a 3D tissue. Many trials have successfully cultured articu-
lar chondrocytes,
18
formed neocartilage tissue,
19
and transplanted
autologous neocartilage to the defect, so biocompatible scaffolds
that afford the proliferation of cartilage and accumulate the matrix
have been widely investigated.
20
As we discussed earlier, numerous attempts have been made
for successful tissue reconstruction using PLGA-based scaffolds
either by PLGA itself or in combination with natural polymers,
such as collagen,
21
and extracellular matrices (ECMs) scaffolds,
that is, SIS
9
,
10
as well as DBPs
8
,
11
,
12
in our previous studies. The
incorporation of bioactive molecules in PLGA is believed to medi-
atecellbehavior,forexample,proliferation,differentiation,andfunc-
tion. To minimize cells lost during the
in vitro
seeding procedure,
we used fibrin to immobilize cells and to provide homogenous cell
distribution in PLGA scaffolds. Fibrin has been widely used for car-
tilage reconstruction purposes.
13
,
22
,
23
We hypothesized that fibrin
would be an ideal cell carrier/transplantation matrix to enhance
in
vitro
chondrogenesis of rabbit articular chondrocytes morphologi-
cally, histologically, biochemically, and phenotypically similar to the
normal hyalinecartilage.
Articular cartilage was aseptically isolated from the femoral
condyles and patellae of six-week-old New Zealand white rab-
bits, and isolated chondrocytes were cultured in a mixture of
equal volume of F12/DMEM. PLGA (mole ratio 50:50, molecular
weight 33,000 g/mole, Resomer RG 503 H) was purchased from
Boehringer Ingelheim Pharma GmbH (Ingelheim, Germany). Micro-
porous 3D PLGA scaffolds (0.2% w/v) were fabricated by the
solvent-casting/salt-leaching technique using sodium chloride as a
porogen. Each sample was assigned into two experimental groups:
culturedchondrocyteswereseededinto(1)PLGAscaffoldswithfib-
rin (fibrin/PLGA) and (2) PLGA scaffolds without fibrin. One mil-
lion cells per scaffold were incorporated and resuspended with
the (1) commercially available fibrin glue kit from Greenplast
R
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