Production and optimization of novel rice husk ash reinforced polycaprolactone/hydroxyapatite composite for bone regeneration using grey relational analysis

Abstract

Polycaprolactone (PCL) is a common biopolymer used in tissue engineering for bone-implant due to several properties i.e. Biodegradability. However, PCL is associated with some disadvantages like poor mechanical strength, and low stiffness. In this study, hydroxyapatite (HAp) sourced from sheep bones was synthesized, and for the first time, locally sourced HAp and silica extracted from rice husk ash (RHA) were reinforced with PCL nanoparticles using the solvent casting route to improve the mechanical strength of the biopolymer composite. Then, the effect of the stirring time, RHA and HAp content on the physical and mechanical properties of the scaffold were studied via the Taguchi design of experiment. The porosity of the fabricated scaffolds falls within 19.4 ± 0.62 - 56.6 ± 0.06% as against 70% obtained for the pure PCL. From the mechanical measurement, the compressive strength of the reinforced composite ranges between 8.6 ± 0.01 and 15±0.1 MPa. The compressive strength data obtained in this study shows that the proposed scaffold had improved mechanical strength equivalent to the minimum required mechanical strength of trabecular bone (4–12 MPa). Also, the addition of the RHA and HAp on PCL increase the hardness and fracture toughness significantly. From the grey relational analysis, the optimal performance from the sixteen experiment (L16) runs was obtained with 20 wt.% of RHA content, 30 wt.% of HAp content and stirring time at 30 min. The sample with the optimum parameters is then recommended for further analysis (i.e. in vitro and in vivo)