Fabrication of porous scaffolds with a controllable microstructure and mechanical properties by porogen fusion technique

Abstract

Macroporous scaffolds with controllable pore structure and mechanical properties were fabricated by a porogen fusion technique. Biodegradable material poly (d, l-lactide) (PDLLA) was used as the scaffold matrix. The effects of porogen size, PDLLA concentration and hydroxyapatite (HA) content on the scaffold morphology, porosity and mechanical properties were investigated. High porosity (90% and above) and highly interconnected structures were easily obtained and the pore size could be adjusted by varying the porogen size. With the increasing porogen size and PDLLA concentration, the porosity of scaffolds decreases, while its mechanical properties increase. The introduction of HA greatly increases the impact on pore structure, mechanical properties and water absorption ability of scaffolds, while it has comparatively little influence on its porosity under low HA contents. These results show that by adjusting processing parameters, scaffolds could afford a controllable pore size, exhibit suitable pore structure and high porosity, as well as good mechanical properties, and may serve as an excellent substrate for bone tissue engineering.

Keywords: composite scaffolds; mechanical property; porogen fusion technique; tissue engineering.

Figure 1.

(A) Scanning Electron Microscopy (SEM) images of scaffolds with the same Biodegradable material poly (d, l-lactide) (PDLLA) concentration of 15% and different porogen sizes: (a) 200∼300 μm (b) 300∼450 μm (c) 450∼900 μm; (B) Scaffold sizes with the same PDLLA concentration of 15% and different porogen sizes calculated from the SEM images.

Figure 2.

The porosity of scaffolds with the same PDLLA concentration of 15 wt% and different porogen sizes.

Figure 3.

The compressive strength of scaffolds with the same PDLLA concentration of 15 wt% and different porogen sizes.

Figure 4.

(A) SEM images of scaffolds with the same porogen size of 300∼450 μm and varying PDLLA concentrations: (a) 10 wt%; (b) 12.5 wt%; (c) 15 wt%; (d) 17.5 wt%; (e) 20 wt%; (B) Scaffold sizes with the same porogen size of 300∼450 μm and varying PDLLA concentrations calculated from SEM images.

Figure 5.

The porosity of scaffolds with the same porogen size 300∼450 μm and different PDLLA concentrations.

Figure 6.

The compressive strength of scaffolds with the same porogen size of 300∼450 μm and different PDLLA concentrations.

Figure 7.

(A) SEM images of scaffolds with the same porogen size 300∼450 μm, the same PDLLA concentration 15 wt%, and different HA contents: (a) 0 wt%; (b) 5 wt%; (c) 10 wt%; (d) 15 wt% (e) 20 wt%. (B) Scaffold sizes with the same porogen size 300∼450 μm, same PDLLA concentration 15 wt%, and different HA contents calculated from the SEM images.

Figure 7.

(A) SEM images of scaffolds with the same porogen size 300∼450 μm, the same PDLLA concentration 15 wt%, and different HA contents: (a) 0 wt%; (b) 5 wt%; (c) 10 wt%; (d) 15 wt% (e) 20 wt%. (B) Scaffold sizes with the same porogen size 300∼450 μm, same PDLLA concentration 15 wt%, and different HA contents calculated from the SEM images.

Figure 8.

The porosity of the scaffolds with the same porogen size 300∼450 μm, the same PDLLA concentration 15 wt%, and different HA contents.

Figure 9.

The compressive strength of scaffolds with the same porogen size of 300∼450 μm, same PDLLA concentration of 15 wt%, and different HA contents.

Figure 10.

Water absorption ability of PDLLA/HA scaffolds with different HA contents as a function of soaking time.