SOLID FREEFORM FABRICATION METHOD APPLIED TO TISSUE SCAFFOLDS - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 621

Figure 31.12. SEMimagesofscaffolds(7.4 × 7.4 × 3.2mm)fabricatedby
MHDS. (a)A 3D PCLscaffold and (b) a 3D PLGAscaffold.
31.2.3 3D Printing
The process of 3DP is an SFF technique used for the rapid manufac-
ture of accurate and complex 3D microstructures from predesigned
patterns of the final structures. The 3DP technology was developed
and commercialized at the Massachusetts Institute of Technology
(MIT) in 1995. Fundamentally, 3DP is also a layer-by-layer fabrica-
tion process, in which the sliced 2D pattern of a computer model
is printed on a fresh layer of powder via an inkjet print head. Suc-
cessive 2D profiles are then printed on a new layer of powder until
the whole 3D model is completed. After the binder has dried in the
powder bed, the finished component is retrieved and the unbound
powderisremoved.The3DPprocessisoneofthemostinvestigated
SFF techniquesfor scaffoldfabrication. 35 - 42
An advantage of 3DP for scaffold fabrication is that commercial
inkjetprinterscanbeeasilyreconstructedtoprintcell-encapsulated
natural polymers at precise positions inexpensively and with high
throughputs. In addition, the scaffold can be manufactured eas-
ily in an ambient environment. Therefore, bio-printers, which are
basedonthetraditional3DPapparatus,havebeendevelopedtoper-
form the computer-assisted deposition of natural materials, includ-
ing bioactive molecules, biomolecules, and viable cells. However, if
the scaffold is designed to be porous, one problem of the powder-
supported and powder-filled structure is the di culty of removing
internal unbounded powder. In addition, the resolution of the scaf-
fold is limited by the fixed nozzle size and the low position accuracy
oftheinkjetprinter.
Lee et al . fabricated scaffolds with large pore sizes and fine fea-
tures using commercially available 3DP systems. 40 They reported