Biomedical Engineering Reference
In-Depth Information
scaffolds. This chapter seeks to review that work and speculate on
the ability of each of these methods to develop effective bone tissue
engineering scaffolds.
25.2 Stereolithography
25.2.1 Scaffold-Manufacturing Process
Becoming commercially available over 20 years ago, SLA is per-
haps the most popular SFF method in use today. SLA utilizes a UV
laser that selectively photopolymerizes a liquid polymer material
(Fig. 25.1). 15 , 19 - 21 To develop a scaffold using SLA, a liquid poly-
mer is placed in a vat and a platform is positioned just below the
surfaceoftheliquidpolymer.Thepolymeristhencross-linkedusing
a laser, which is guided by a mirror to cross-link the polymer to the
shape specified. The photopolymerization only takes place at sur-
faceofthepolymer.Oncealayeriscomplete,theplatformislowered
one layer and recoated with the liquid polymer and subsequent lay-
ersarecross-linked,followingthesamemethod.Aftercompletionof
the scaffold, it is removed from the vat, excess polymer is removed,
and the scaffold is placed in a UV oven to complete the curing
process. SLA has the ability to create custom-shaped scaffolds with
Figure 25.1. A schematic of the stereolithographic process. 1 , 20 The
mirror-guidedlasercross-linksthepolymeratthesurfaceofthevatandcan
move in the x and y directions. The elevator lowers the completed scaffold
one layer in the zdirection.
 
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