Biodegradable polylactide/hydroxyapatite nanocomposite foam scaffolds for bone tissue engineering applications

Abstract

Supercritical carbon dioxide processing of poly-L-lactide (PLLA)/hydroxyapatite (nHA) nanocomposites was investigated as a means to prepare foams suitable as scaffolds in bone tissue engineering applications. For given foaming parameters, addition of nHA to the PLLA gave reduced cell sizes and improved homogeneity in the size distribution, but did not significantly affect the degree of crystallinity, which remained of the order of 50 wt% in all the foams. The compressive modulus and strength were primarily influenced by the porosity and there was no significant reinforcement of the matrix by the nHA. The mechanical properties of the foams were nevertheless comparable with those of trabecular bone, and by adjusting the saturation pressure and depressurization rate it was possible to generate porosities of about 85 %, an interconnected morphology and cell diameters in the range 200-400 lm from PLLA containing 4.17 vol% nHA, satisfying established geometrical requirements for bone replacement scaffolds.

Supercritical processing of CO 2 -philic polyhedral oligomeric silsesquioxane (POSS)-poly( l -lactic acid) composites

“…According to the multiple comparisons carried out using Dunnett's T3 test, the difference between the two average pore sizes were statistically significant at α=0.05 level, indicating that smaller average pore sizes were obtained with slower venting rate. Similar observation has been reported previously by Delabarde et.al, which used hydroxyapatite as additive in PLLA films, attributing the smaller cell diameters to possible crystallization occurred during slower venting rates [35].…”

“…The modulus and compressive strength of the foam were improved up to 250 MPa and 6 MPa, respectively in case of HAp presence. In another study, however, addition of HAp caused smaller pore size with more homogeneous structure [35]. No significant change on the mechanical properties of PLLA was reported upon addition of up to 4.17vol% HAp.…”

Evaluation of the novel three-dimensional porous poly (L-lactic acid)/nano-hydroxyapatite composite scaffold

“…The PLLA/n-HA composite scaffold can be fabricated by many methods including film casting [12], particulate leaching [13] and gas foaming [14]. Although these methods are convenient, they fail to accurately control the pore size and porosity of the scaffold.…”

Repairing rabbit radial defects by combining bone marrow stroma stem cells with bone scaffold material comprising a core-cladding structure

“…The seed cells need to proliferate and differentiate to osteoblasts rapidly, thus promoting generation of new bone tissue. As a glycoprotein on the cell surface, alkaline phosphatase acts as a marker indicating the differentiation of cells and osteogenesis (Delabarde et al, 2012).…”