Biomedical Engineering Reference
In-Depth Information
FIGURE 6.6
Neutrally charged PEG monomer.
6.5
INTEGRATIVE SUPPORT MATERIALS
The role of hydrogel in bioprinting is recognized for its biocompatibility. However, hydrogels usually lack
mechanical strength. Some research groups have integrated the use of hard thermoplastic material such
as polycaprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA) with soft materials (hydrogel) to
enhance the mechanical strength of constructs and ensure better shape fidelity. The solid scaffold provides
a suitable macrostructure and creates open pore geometry with highly porous surface and microstructure.
Since these materials are synthetic, their degradation rate and cytotoxic effects can be controlled. The use
of soft and hard polymers also helps to enhance cell adhesion and proliferation on the scaffold.
The conditions required to process thermoplastic PCL and PLGA are unfavorable for cells. Hence,
most hybrid bioprinting systems comprise two components: (i) dispensing thermoplastic-melt plotting
system and (ii) dispensing hydrogel/cell materials.
Table 6.2
summarizes some of the current biomate-
rials used in bioprinting along with the different printing techniques used.
Table 6.2
Hydrogel used for bioprinting classified according to the type of material used
Materials
Printing technique
References
Soft
Natural Hydrogel
Alginate
Ink-jet Printing
(
Xu et al., 2013b
)
Ink-jet Printing
(
Xu et al., 2012
)
Pneumatic Extrusion
(
Ozbolat et al., 2014
)
Pneumatic Extrusion
(
Ahn et al., 2013
)
Pneumatic Extrusion
(
Huang et al., 2013
)
Pneumatic Extrusion
(
Lee et al., 2013
)
Pneumatic Extrusion
(
Fedorovich and Wouter, 2011
)
Pneumatic Extrusion
(
Shim et al., 2012
)
BioLP / AFA-LIFT / MAPLE-DW
(
Guillotin et al., 2010
)
Positive Displacement Extrusion
(
Sawkins et al., 2012
)
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