Characterization and Degradation Behavior of Polylactic Acid Composite Incorporated with Egg-Shell Derived Hydroxyapatite for Bone Repair

This study explored eggshells as an eco-friendly and cost-effective material for synthesizing hydroxyapatite. The phase compositions and morphological structure of polylactic acid composite with and without co-doped hydroxyapatite addition via a melt blending approach were evaluated. Furthermore, the biodegradation profile of the polylactic acid composite in phosphate buffer solution was studied. The concentrations of PLA/HAp, PLA/7.5MgO-7.5ZnO, and PLA/12.5MgO-2.5ZnO samples, respectively, were examined in this study. The results of morphological evaluation showed a well-distributed irregular spherical phase of hydroxyapatite. Meanwhile, the co-doped hydroxyapatite phases have variations in sizes and shapes. The polylactic acid composites showed fractured, rough, and honeycomb surfaces with interconnected pores suitable for cell propagation and enhancement, and the elemental composition proved precipitation of apatite formation. Characteristics of absorption bands of the hydroxyapatite, magnesium, zinc, and polylactic acid were present, respectively. The XRD spectra confirmed the presence of crystalline and semi-crystalline structures with percent crystallinity of 48.57%, 56.64%, and 60.08%, respectively. Meanwhile, the addition of the co-doped hydroxyapatite results in shifts in the 2θ angles of the crystal phases. The biodegradation study revealed the beneficial role of reinforcing polylactic acid composite with biogenic hydroxyapatite and hybrid doped hydroxyapatite as fillers and their synergetic effect with the pH of 7.08±0.21, 6.63±0.46, & 7.28±0.44, the porosity of 52.26±7.29, 48.57±6.74, & 43.72±5.07 %, and the degradation rate (weight loss) of 51.83±7.03, 48.16±6.85, & 43.66±5.46, respectively. Findings revealed that the current study aligns with the sustainable biodegradable composite used in bone tissue repair and hence contributed towards sustainable material without polluting the environment.