Croaker Fish Bone-Derived Hydroxyapatite as a Sustainable Source for 3D-Printed Scaffolds for Bone Regeneration

The use of biogenic hydroxyapatite as a sustainable and bioactive alternative to synthetic ceramics has attracted increasing attention for 3D-printed scaffolds in bone tissue engineering. In this work, calcium alginate-based scaffolds reinforced with commercial (cHA) and biogenic hydroxyapatite (bHA) obtained from croaker fish bones (Micropogonias furnieri) were fabricated by 3D printing using hydroxyapatite contents ranging from 10% to 20%. Both hydroxyapatites exhibited hexagonal structures, and all formulations showed rheological behavior suitable for extrusion-based printing. Structural analyses revealed increased diffraction peak intensity with higher hydroxyapatite content, while FTIR spectra showed no significant structural changes. Hydroxyapatite addition increased the compressive modulus, although higher loadings reduced maximum resistance and produced denser, less porous structures. After 14 days in simulated body fluid, scaffolds containing 10% bHA favored apatite deposition, evidenced by increased phosphorus levels. In vitro assays using MC3T3-E1 pre-osteoblasts demonstrated biocompatibility, with metabolic viability above 70% and no toxicity. The 10% bHA formulation also enhanced cell proliferation, adhesion, and migration without increasing reactive oxygen or nitrogen species. Alizarin Red staining indicated osteogenic potential, while micronucleus assays with CHO-K1 cells confirmed the absence of genotoxicity. These findings highlight the potential of biogenic hydroxyapatite scaffolds for bone tissue engineering.