Enhanced bioactivity of regenerated eggshell membrane hydrogels with strontium-doped hydroxyapatite for potential bone tissue regeneration

Tissue engineering has emerged as a promising alternative for bone repair. Avian eggshell membrane stands out among potential biomaterials due to its low immunogenicity, similarity to the extracellular matrix, and widespread availability. This study focuses on developing a bone ingrowth support system from a regenerated avian eggshell membrane. The collagenous and non-collagenous protein fractions were developed into hydrogels with poly-(vinyl alcohol) (PVA) via freeze-thawing, followed by their incorporation with hydroxyapatite and strontium-doped hydroxyapatite synthesized from the eggshell cuticle. Their physicochemical analysis revealed the biphasic nature of hydroxyapatite and Ca/P and (Ca + Sr)/P ratios of 1.25 and 1.27, respectively. The characterization with ATR-FTIR revealed the identification of amide I, amide III, and –OH functional groups at 1639 cm⁻¹, 1264 cm⁻¹, and 3308 cm⁻¹, respectively, for all the hydrogels, along with a broad peak observed between 16° and 24° (2θ) in the XRD data. Evaluation of hydrogels’ morphology, degradation (40%−50%), swelling (162%−750%), mechanical properties (1.4 MPa–3.5 MPa), and biocompatibility with osteoblasts (>87%) demonstrated their suitability for bone regeneration. Further, histopathological examination of rat tibial bone demonstrated enhanced bone repair, with the findings strongly suggesting the potential application of the regenerated avian eggshell membrane in promoting bone regeneration.