Comparative Study on the Effect of Filler Size on the Mechanical Properties of Poly(DL-Lactide-Co-Glycolide) Acid – Hydroxyapatite Composite Scaffolds Available to Purchase

Tissue engineering is an emerging alternative treatment for various diseases and injuries. The use of hydroxapatite composites for bioscaffolds has shown to improve the osteoconductivity. Studies in the literature have been performed to examine the advantages of using this composite in the biological aspects of tissue engineering; however, few studies have been on the synthesis and mechanical properties of these bioscaffolds. These properties are especially important in load bearing applications like in bone tissue engineering. In this study, poly(DL-lactide-co-glycolide) acid (PLGA) and hydroxyapatite (HA) were used to fabricate gas-foamed/salt leached scaffolds. Micro and nano-scaled HA particles were melt-compounded with PLGA using a twin-screw compounder. The composite material was dry blended with salt particles at a salt-to-polymer mass ratio of 5:1. From observations of micrographs taken with a scanning electron microscope, both the micro and nano-HA particles were shown to be well dispersed within the polymer matrix. The thermal properties were examined using differential scanning calorimetry, and the effect of the compositions on the glass transition temperature, T_g, was studied. The T_g was not significantly changed with the addition of HA particles from 0 to 20 wt%. Similarly, thermogravimetric analysis showed that the thermal degradation temperature remained at approximately 320 °C. The mechanical properties of the scaffolds were tested in compression. At the same composition, the scaffolds fabricated with the nano-HA showed an increase in modulus and strength. The results found in this study are important in developing novel biodegradable scaffolds with a focus on improving the mechanical properties of the scaffolds for bone tissue engineering applications.