The determination of biomechanical properties of ten different bone graft formulations containing eggshell and eggshell membrane powder

The biomechanical stability of bone graft materials is a crucial determinant of clinical success in bone regeneration procedures. This experimental study aimed to evaluate the mechanical and structural properties of ten different bone graft formulations prepared using eggshell and eggshell membrane powder, which represent a biocompatible and natural alternative source of calcium-based biomaterials. Each formulation was composed of varying ratios of eggshell powder, membrane extract, and calcium phosphate compounds. The samples were cross-linked with glutaraldehyde (GA) and incubated in simulated body fluid (SBF) for 48 hours and one week to assess their in vitro stability. The analyses included percentage weight loss, compressive strength (MPa), and fracture strength (MPa) measurements. The findings revealed that Formulas 3, 4, and 7 demonstrated the lowest weight loss rates (ranging between 2.8–3.5%) after both 48-hour and 1-week immersion periods. Formula 4 exhibited the highest mechanical performance, with a mean compressive strength of 8.12 ± 0.21 MPa and fracture strength of 4.86 ± 0.18 MPa. Statistical analysis confirmed that GA cross-linking significantly enhanced the structural integrity and mechanical resistance of the graft blocks (p<0.05). In conclusion, eggshell- and membrane-based composite grafts demonstrated mechanical properties comparable to synthetic calcium phosphate materials, while offering the advantages of biocompatibility, biodegradability, and cost-effectiveness. These results indicate that eggshell-derived biocomposites may serve as promising biomaterials for bone tissue engineering and regeneration applications. Keywords: Eggshell, Eggshell membrane, Bone graft, Biomechanical strength, Tissue engineering, SBF