Polylactic acid–phosphate glass composite foams as scaffolds for bone tissue engineering

Abstract

Phosphate glass (PG) of the composition 0.46(CaO)-0.04(Na(2)O)-0.5(P(2)O(5)) was used as filler in poly-L-lactic acid (PLA) foams developed as degradable scaffolds for bone tissue engineering. The effect of PG on PLA was assessed both in bulk and porous composite foams. Composites with various PG content (0, 5, 10, and 20 wt %) were melt-extruded, and either compression-molded or foamed through supercritical CO(2). Dynamic mechanical analysis on the bulk composites showed that incorporating 20 wt % PG resulted in a significant increase in storage modulus. Aging studies in deionized water in terms of weight loss, pH change, and ion release inferred that the degradation was due to PG dissolution, and dependent on the amount of glass in the composites. Foaming was only possible for composites containing 5 and 10 wt % PG, as an increase in PG increased the foam densities; however, the level of porosity was maintained above 75%. PLA-T(g) in the foams was higher than those obtained for the bulk. Compressive moduli showed no significant reinforcement with glass incorporation in either expansion direction, indicating no anisotropy. Biocompatibility showed that proliferation of human fetal bone cells was more rapid for PLA compared to PLA-PG foams. However, the proliferation rate of PLA-PG foams were similar to those obtained for foams of PLA with either hydroxyapatite or beta-tricalcium phosphate.

Osteogenesis and angiogenesis: The potential for engineering bone

“…Ruhe et al (2005b) showed bioactive factors to be incorporated into (PLGA/ Ca-P cement) composites and could be slowly released. Furthermore, the combination of osteogenic growth factor release (BMP-2) from polymer scaffolds such as PLA and the addition of preosteogenic cells have further increased the possibility of engineering bone (Rose et al, 2004;Yang et al, 2004;Montjovent et al, 2005;Montjovent et al, 2007;Georgiou et al, 2007), whilst Jansen et al (2005) demonstrated orthotopic bone formation in a rabbit cranial defect model stimulated in rhTGFβ1 and rhBMP-2 CaP cement and Titanium-fibre mesh scaffolds.…”

Quantification of fluid shear stress in bone tissue engineering scaffolds with spherical and cubical pore architectures

“…This was carried out for a PDLLA scaffold that had a spherical architecture, with a pore size of 300µm and porosity of 90% (Blecha et al 2010;Bose et al 2013;Georgiou et al 2007;Karande et al 2004;Silva et al 2006;Tan et al 2011). Firstly, we investigated the influence of inlet fluid velocity on the WSS using the similar FSI model to that described in Section 2.4.…”

Bioactive composites for bone tissue engineering

“…Haimi et al [55] cultured human adipose stem cells on PLA reinforced with between 0 and 20 wt% of either β-TCP or a bioactive glass based on 5%Na 2 O-7.5%K 2 O-3%MgO-25%CaO-59.5%SiO 2 with porosity produced by freeze drying. After 2 weeks, compared to nonreinforced PLA scaffolds, statistically more cells were seen on the scaffolds reinforced with β-TCP and statistically less on the scaffolds reinforced with the bioactive glass.…”