Biomedical Engineering Reference
In-Depth Information
Biodegradability
Biocompatibility
Porosity
Surface
chemistry
Mechanical
requirements
Material
Surface modification
Bulk modification
Design
Production technique
Biofactor
delivery
Moldability
Cell adhesion,
Proliferation,
Differentiation
Transport
requirements
Fig. 9.1
Schematic illustration integrating the complex multi-disciplinary needs which determine
the constraints for the ideal scaffold fabrication design
both conventional and rapid prototyping (RP) techniques have been explored.
Conventional scaffold fabrication set-ups include techniques such as particulate
leaching [
84,
112-
114
] , gas foaming [
113-
116
] , fi bre networking [
117,
118
] ,
phase separation [
119,
120
] , melt moulding [
121,
122
] , emulsion freeze drying
[
123,
124
] , solution casting [
125,
126
] , freeze drying [
80,
86,
127
] and combi-
nations of those. Conventional/classical approaches are defined as processes
that create scaffolds with a continuous, uninterrupted pore network. Nonetheless,
they completely lack long-range micro-architectural channels [
18
] . Other
reported disadvantages involve low and inhomogeneous mechanical strength,
limited porosity and insufficient interconnectivity, inability to spatially design
the pore distribution (internal channels) and pore dimensions and difficulty in
manufacturing patient-specific implants (control over external geometry is lim-
ited) [
18,
128
]. Furthermore, the use of organic solvents during processing is
seen as a second major drawback in addition to the above-mentioned architec-
tural drawbacks. The presence of organic solvent residues can pose significant
constraints related to toxicity risks and carcinogenetic effects [
18
] . Despite
some adaptations over the years the scaffold design remains process dependent
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