Computational Modeling of Tissue Engineering Scaffolds as Delivery Devices for Mechanical and Mechanically Modulated Signals - Computational Modeling in Tissue Engineering - page 126

Fig. 3 Schematic of the one-stage bone-transport surgical procedure applied to the femur a and
b three-dimensional (3D) micro-computed tomograph reconstruction of the critical sized defect
control (unhealed after 16 weeks) and the defect surrounded by healthy periosteum in situ (healed
completely after 16 weeks) [ 28 ], used with permission. c Computer Aided Design (CAD)
drawings of 3D scaffold designs for treatment of CSD in the cranium [ 13 , 18 ], adapted from [ 13 ]
and used with permission . Please refer to online version of chapter for color version of the figure

recently (Fig. 3 a, b) [ 28 ]. The technique results in woven bone regeneration
in CSD zone within 2 weeks of surgery. Recent studies using a periosteum
replacement implant cum delivery device have shown that incorporation of peri-
osteal factors, including periosteum derived multipotent cells and periosteal strips
without patent blood supply, around the defect zone can improve defect infilling
compared to that observed with baseline controls [ 26 ]. For cranial CSDs, polymer
scaffolds have been designed, some of which also incorporate MSCs (Fig. 3 c)
[ 13 , 18 ]. This scaffold consists of polypropylene fumarate (PPF) mixed with a
photoinitiator, which can be cross-linked by exposing it to a concentrated flood of
UV light [ 13 ]. MSCs are seeded into the scaffold before implantation of this
scaffold into cranial CSD zone. Broad interdisciplinary studies are in progress
to elucidate mechanisms of tissue building, incorporating fundamentals of com-
putational and experimental mechanics, polymer science, rapid prototyping,

biochemistry, and stem cell mechanobiology [ 39 , 41 ].

3 Mechanical Characteristics of Embryonic Stem Cells

Biophysical and biochemical cues define the local environment of the cell and play
a key role in determining cell behavior including migration, proliferation, and
differentiation; cumulatively, these cell behaviors result in de novo generation of
tissue or bottom up tissue engineering. During embryonic development, cells
respond to biophysical and biochemical signals to form the template of the
complete organism. Defining the tissue template specifications to mimic the
environment of the condensed mesenchyme (Fig. 4 ) during development allows