Photocrosslinkable Materials for the Fabrication of Tissue-Engineered Constructs by Stereolithography - Tissue Engineering: Computer Modeling, Biofabrication and Cell Behavior - page 158

Fig. 9 Left : PDLLA scaffold built by stereolithography [ 70 ]. Right : SEM images of the PDLLA
3-FAME/NVP stereolithographic scaffold [ 44 ]
able PLA resin for the fabrication of 3D scaffolds. The potential of this polymeric
material for neuronal tissue engineering applications was evaluated through the cul-
ture of rat primary Schwann cells and SH-SY5Y neuroblastoma cell line. Cells
showed good adherence to the methacrylated PLA films, assuming spindle-like and
flat cell morphologies when cultured on the 3D scaffolds. Results revealed the neu-
rocompatibility of the developed constructs as well its ability to support cell prolif-
eration.
Methacrylate end-functionalized PTMC macromers were used by Schüller-
Ravoo et al. [ 89 ] to produce 3D constructs with a gyroid pore network. Before
processing, the macromers were diluted using non-reactive propylene carbonate
to decrease the viscosity and increase the processing temperature. The resulting
network films exhibited high flexibility and elasticity, while the 3D porous scaf-
folds presented porosities in the range of 53-66 %. Meyer et al. [ 72 ]usedthe
2PP technique to produce 3D vessels with a branched tubular structure by, irra-
diating α, ω -polytetrahydrofuranether-diacrylate polymers. Tubular structures were
obtained with a height of 160 µm, an inner diameter of 18 µm and a wall thickness
of approximately 3 µm.
Synthetic hydrogels have also been processed through stereolithographic pro-
cesses, such as poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), poly(buty-
lene oxide) (PBO), poly(hydroxybutyrate) (PHB), polyacylamide, poly(hydroxy-
propyl methacrylamide) (PHPMA), poly(2-hydroxyethyl methacrylate) (PHEMA)
and PEG [ 8 ].
PEG hydrogels are the most commonly used for conventional stereolithography
[ 91 ], microstereolithography [ 63 ] and 2PP [ 80 ]. These materials exhibit high hy-
drophilicity, excellent biocompatibility, and can be functionalized with photoreac-
tive end groups, such as acrylates or methacrylates, allowing the photopolymeriza-
tion process [ 2 ]. Furthermore, PEG hydrogels can be susceptible to the hydrolytic
degradation by the cleavage of the ester bonds, through either the introduction of
proteolytically degradable peptide sequences into the backbone or by blending PEG
with other biodegradable polymers [ 3 , 24 , 91 ]. Several works showed that PEG-
based hydrogels can be modified with cell adhesive peptides, improving the cellular