3D PRINTING AND NANOMANUFACTURING - 3D Bioprinting and Nanotechnology in Tissue Engineering and Regenerative Medicine - page 38

hyaluronic acid ( Gauvin et al. , 2012 ). Although a certain level of bioactivity has been demonstrated,
the surfaces of GMHA scaffold are ready for further modification to incorporate more cell-adhesive
proteins like laminin ( Hribar et al. , 2014 ).
Laser-based stereolithography (SLA) patterns photocrosslinkable hydrogels or polyesters to cre-
ate a microenvironment in 3D structure using UV laser. The technology was applied to PEGDMA
for 3D scaffold ( Mapili et al. , 2005 ), and to PEGDA for cantilever bioactuator ( Chan et al. , 2012 ) or
cell-encapsulated 3D scaffold ( Chan et al. , 2010 ). It was also employed to 3D bone scaffold with a
poly(propylene fumarate) (PPF)/diethyl fumarate (DEF) mixture ( Lee et al. , 2007 ).
In contrast to the point-by-point processing by laser-based SLA, optical projection stereolithogra-
phy employs DMD to fabricate 3D hydrogel objects layer-by-layer using UV irradiation. Suri et al.
demonstrated the freeform fabrication of nerve regeneration scaffolds with complex microarchitecture
using GMHA as shown in Figure 2.7 ( Suri et al. , 2011 ). With an improved version of the dynamic opti-
cal projection stereolithography (DOPsL) system, Soman et al. succeeded in using GelMA to fabricate
FIGURE 2.9
SEM images of woodpile structures fabricated from PEGDA by TPP: (a) large view, (b) close-up view ( Zhang and
Chen, 2011 ).
FIGURE 2.10
SEM images of microdot array with various feature sizes fabricated from PEGDA by TPP ( Zhang and Chen, 2011 ).