Control and Monitoring of Scaffold Architecture for Tissue Engineering - Biomaterials Fabrication and Processing - page 83

FIGURE 3.7 OCT image of a porous PLLA scaffold generated by single porogen technique: (a) cross-section
and (b) top view from reconstruction. The pore size ranged from 255 to 350 µm.
3.5.3 D ISCUSSION
Development of relatively simple, fast, and highly productive techniques to manufacture scaffolds
with the required external and internal architecture is an interesting research area in biomaterials
and TE fi eld. Its success will greatly benefi t and promote the study of engineered tissues. The main
objective for achieving high-quality scaffolds is to increase pore interconnection at the same time
maintaining the mechanical strength in order to overcome the poor diffusion effi ciency of nutrients
and gas within the center of scaffolds. Furthermore, the internal architecture should fi t the require-
ment for specifi c tissues.
In the reported case study, we have developed a dual porogen system for solvent-evaporation and
salt-leaching technique. OCT and SEM image have shown that the pore interconnection increased
with this technique. It has been found that it can also tailor the interconnectivity by changing the per-
centage of the second porogen, that is, naphthalene. Sodium chloride and naphthalene have different
mechanisms for pore formation within scaffolds. Macropores are created by dissolving the NaCl crys-
tal in water, leaving an empty space within the polymer composites (see Figure 3.7), while naphthalene
remains undissolved. Thus, during the removal of NaCl, naphthalene remained in the scaffolds until
the macropores were formed (see Figure 3.3). In this study, either 255-350 µm or 106-255 µm pores
were formed fi rst. Uniquely, naphthalene volatilized and sublimed at room temperature. Thus, the