Box-Behnken experimental design for the process optimization of catfish bones derived hydroxyapatite: A pedagogical approach

The present work describes the synthesis, optimization, and evaluation of synthesized hydroxyapatite (HAp) from catfish bones (CB). This is with a view to achieving optimum processing conditions and sustainable pedagogical approaches for the preparation of hydroxyapatite scaffolds for tissue engineering. The catfish bones derived hydroxyapatite were prepared through conventional sintering, and low-cold compaction pressure (1 MPa), while the Box-Behnken statistical design tool was used in determining the optimum preparation conditions. Analytical studies were performed on the synthesized HAp to elucidate the physico-chemical and mechanical characteristics of the designed formulation. Three parameters; heating temperatures, holding times, and, sieve sizes were adopted to establish a significant correlation on the physico-mechanical characteristics of the fabricated HAp scaffolds. From the design of experiment (DOE), heating temperature proved to have the most significant effect on the material's mechanical and physical properties when compared to holding times and sieve sizes, with compressive strength (13 MPa), density 1.856 g/cm³ and fracture toughness (2.407 MPa m^1/2) observed to be the most improved properties in that order. The physico-mechanical properties of the hydroxyapatite scaffolds reached an optimum at 900 °C, 2 h 22 min holding time, and at a particle size of 100 μm. X-ray diffraction and Fourier transform infra-red studies showed that at every experimental run, optimum run (R6) inclusive, hydroxyapatite with remarkable purity was formed. This study, therefore, illustrates the optimum process for the synthesis of catfish bones derived hydroxyapatite revealing the most significant interactions responsible for achieving clinically useful hydroxyapatite scaffolds with a computational pedagogical approach that is useful for innovations in bioengineering education.