Biomedical Engineering Reference
In-Depth Information
TABLE 7.1
Summary of fabrication techniques for porous 3D bioscaffolds.
Fabrication Techniques
Process Description
References
Conventional scaffolds
Salt-leaching method
(i) Insoluble (porogen) particles are added to a polymer solution
(ii) Solution is cast into a mold and the solvent allowed to evaporate
(iii) Matrix is then placed in solvent to dissolve porogen particles
49-51
Gas-foaming method
(i) CO
2
and a polymer are placed in a chamber and the pressure
increased until the two are miscible
(ii) The pressure is lowered and the gas particles begin to cluster
(iii) Pores form as gas evolves
(iv) Often combine with particle-leaching step
52,53
Textile fiber-bonding method
(i) A fiber mesh is submerged into a polymer solution or placed in a
mold and a polymer solution is poured into the mold
(ii) The solvent is allowed to evaporate and the polymers are heated
to the melting point of the fiber mesh to create welded points
(iii) The non-fiber polymer is selectively dissolved and the bioscaffold
is vacuum dried
54, 55
Solid free-form fabrication
(i) Computer-aided design (CAD) tools are used to produce a digital
representation of the desired bioscaffold
(ii) Polymeric material is then deposited in a layer-by-layer manner to
produce the bioscaffold
50, 56, 57
Hydrogels
(i) Natural or synthetic hydrophilic polymers are placed in aqueous
solution
(ii) Chemical or physical crosslinks are used so the polymer does not
dissolve
58, 59
Nanofibrous scaffolds
Electrospinning
(i) A high voltage is applied to a polymer solution
(ii) A stream forms if there is sufficient chain entanglement
(iii) Fibers are deposited onto grounded collector of variable geometries
60-62
Thermally induced phase
separation
(i) A polymer solution is frozen
(ii) The polymer and solvent phases separate at lower temperatures
(iii) The solvent phase is evaporated through lyophilization
12, 43
Self-assembly
(i) Amphiphilic molecules, typically peptides, are placed in aqueous
solution
(ii) Hydrogen bonding, ionic, electrostatic, hydrophobic, and van der
Waals interactions can cause the molecules to form fibers
63, 65
Special scaffolds
Native tissue derived
(i) Allogeneic or xenogeneic tissues are processed in proprietary
ways to leave fibrous protein and carbohydrate ECM
(ii) Other chemical and physical modifications are made to ensure
bioscaffold's stability
in vivo
66, 67
Injectable scaffolds
(i) Prepare hydrogel or ceramic solution
(ii) Add cells and other material
68, 69
Inorganic ceramics/
composites
(i) Gas-foaming, free-form fabrication techniques
70-72
