BIOLOGICAL IMPLICATIONS OF POLYMERIC SCAFFOLDS FOR BONE TISSUE ENGINEERING DEVELOPED VIA SOLID FREEFORM FABRICATION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 489

the study a Chinese hamster ovary cell line was used to demon-
strate the viability of the method. Cells were suspended in the
photopolymer solution before exposure to the laser and were
encapsulated upon polymerization. The cells remained viable
throughout the encapsulation procedure. The scaffolds used in this
particular study lacked the mechanical properties for effective use
in hard-tissue applications, like bone, but the ability to encapsulate
cellsinascaffoldcouldbeappliedtobonetissueengineeringtocre-
ate a uniform cellular seeded scaffold with a controlled architecture
and cell distribution.
Scaffold material must be liquid and photopolymerizable for use
in SLA, thus greatly limiting the scaffold material choice. Despite
this the ability to be used in PPF scaffold fabrication makes SLA
a promising method to produce bone tissue engineering scaffolds.
Morecellstudiesareneededtofullyassessthecellinteractionswith
SLA-fabricated scaffolds, but SLA has been shown to create scaf-
folds with feature architecture and porosity small enough for bone
tissue engineering purposes. The osteoconduction of scaffolds fab-
ricated via indirect SLA has been demonstrated, but the indirect
approach used to create these scaffolds adds an extra manufac-
turing step and could lead to uncontrolled microarchitecture in
the scaffolds. This makes the indirect SLA approach less clinically
viable than a direct approach. The possibility of the incorporation
ofcellsandbiomoleculesdirectlyintothescaffoldisanotherimpor-
tant attribute of SLA. Growth factors such as bone morphogenetic
protein-2 (BMP-2) and transforming growth factor-beta 2 (TGF- β 2)
have been shown to have great effects on the osteoinduction and
osteoconduction of bone tissue engineering scaffolds. 41 - 43 Direct
incorporation of these heat-sensitive materials into scaffolds can-
not be achieved by SFF methods that require high heat such, as sin-
tering. Incorporation of growth factors as well as cells through SLA
could create dynamic bone tissue engineering scaffolds with a uni-
form cell population, growth factors to enhance osteogenesis, and
controlled, reproducible scaffold architecture. The use of PPF, pos-
sibledirectincorporationofbiomolecules,andnanoscaleresolution
makes SLA one of the most promising SFF techniques for bone tis-
sue engineering, yet additional cell studies using SLA are needed to
realize this promise.