Synthesis of silicate glass/poly(l-lactide) composite scaffolds by freeze-extraction technique: Characterization and in vitro bioactivity evaluation

The main objectives of the present study were to fabricate the silicate glass/poly(l-lactide) composite scaffolds for bone engineering applications, by using the freeze-extraction technique, and to evaluate the possibility for optimizing their degradation rate by changing their glass content. The scaffolds characterized by SEM-EDXA, FT-IR, TGA and XRD. Examination of the SEM microphotographs revealed that the pore size of the scaffolds decreased as the glass content increased. The neat polymer scaffold (PLA) had a highly interconnected porous structure with a maximum pore size of 200 μm. For the composite scaffold containing glass content up to 25 wt% (SP25) and up to 50 wt% (SP50), the maximum pore size was 40 μm and 20 μm respectively. The apparent porosity was 56.56%, 52.49% and 48.74% for PLA, SP25 and SP50, respectively. The results of the degradation study showed that the water absorption of the scaffolds decreased by increasing their glass content, It reached finally to 48.71%and 30.93% for SP25 and SP50, respectively. It revealed that also the weight loss of the scaffolds increased by increasing the glass content. The final weight loss was around 5.44%, 9.31% and 26.17% for the PLA, SP25 and SP50, respectively, indicating that it was possible to modulate the degradation rate of the scaffolds by varying their glass content. In addition, the pH measurement of incubation medium indicated that the glass could compensate the acidic degradation products of the polymer. In vitro bioactivity evaluation showed that the composite scaffolds were able to induce the formation of hydroxyapaptite layer on their surfaces, demonstrating their potential application in bone engineering.