HYBRID POROUS SCAFFOLDS OF BIODEGRADABLE SYNTHETIC POLYMERS AND COLLAGEN FOR TISSUE ENGINEERING - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 421

skeleton can also be formed into any desired shape to define the
shape and structure of tissue-engineered tissues and organs.
Thecollagenmicrospongesintheporesandcoatedcollagenlayer
on the surface can promote interaction with cells and thus facili-
tatecelladhesionanddistribution.Theintroductionofcollageninto
the synthetic polymer sponges can also improve the wettability of
thesyntheticpolymersponges.Thesurfacepropertiesofbiodegrad-
able synthetic polymer sponges are hydrophobic. This property
inhibits infiltration of the cell suspension solution into the porous
scaffolds and, therefore, hinders smooth cell seeding. Pretreatment
such as prewetting with ethanol, hydrolysis with an alkaline aque-
oussolution,andplasmatreatmentisrequiredtochangethesurface
property from hydrophobic to hydrophilic to facilitate cell seeding
intothehydrophobicscaffolds.However,thewaterwettabilityofthe
PLGA-collagenhybridspongeisincreased.Improvementofwettabil-
ity facilitates cell seeding and cell infiltration into the inner parts of
the scaffolds.
The PLGA-collagen hybrid sponge has been used for the cul-
ture of bovine articular chondrocytes. 13 APLGAspongewasused
as a control. The chondrocytes were seeded into the PLGA sponge
and PLGA-collagen hybrid sponge and cultured in vitro in a serum
medium in a 5% CO 2 atmosphere at 37 ◦ C. Cell seeding into the
PLGA sponge requires prewetting of the sponge with an aqueous
ethanol solution. However, cell seeding in the PLGA-collagen hybrid
spongebecomesmucheasierduetoitsimprovedwettability.Simply
droppingthecellsuspensionsolutionontothePLGA-collagenhybrid
sponge causes the cell solution to penetrate the hybrid sponge. The
cell-seeding e ciency of the PLGA-collagen sponge was higher than
that of the PLGA sponge. More cells adhered to the PLGA-collagen
hybrid sponge than to the PLGA sponge because the collagen pro-
moted the cell adhesion in the hybrid sponge. The chondrocytes
proliferated in the hybrid sponge during culture. The chondrocytes
and their extracellular matrices gradually occupied the space in the
hybridsponge.BiochemicalanalysisdemonstratedthattheDNAand
proteoglycan content in the hybrid scaffold increased with culture
time.Mostofthechondrocytesafterfourweeks'culture,andalmost
allthecellsaftersixweeks,maintainedtheirphenotypicallyrounded
morphology.ImmunohistologicalstainingoftypeIIcollagenshowed