Performance evaluation of waste-derived silica and marine collagen- enriched PLA biocomposites for bone regenerative applications

This study investigated the performance of alkali-treated biosilica and marine collagen reinforced PLA biocomposites for bone regenerative applications by evaluating their mechanical, fatigue, swelling, degradation, and SEM characteristics. Three composite formulations containing equal proportions of biosilica and collagen (0.5, 1.5, and 2.5 vol.% each) were fabricated as PMC0, PMC1, and PMC2, and compared with neat PLA. Among all compositions, PMC1 exhibited the best mechanical performance, achieving a tensile strength of 123 MPa, flexural strength of 137 MPa, impact energy of 2.71 J, and hardness of 89 Shore D. It also showed the highest fatigue life, reaching 26,790, 24,727, and 22,603 cycles at 25%, 50%, and 75% UTS, respectively, owing to uniform filler dispersion and strong interfacial bonding promoted by alkali treatment. In contrast, PMC2 exhibited the greatest swelling and degradation behavior, recording 1.995 wt.% swelling and 0.547 wt.% degradation after 4 weeks, which resulted from its higher hydrophilic filler content and increased water penetration. SEM analysis supported these findings by revealing homogeneous filler distribution and excellent matrix–filler adhesion in PMC1, while PMC2 showed localized filler agglomeration and microvoid formation. Overall, PMC1 provided the optimum balance of strength, hardness, and fatigue resistance, whereas PMC2 offered enhanced biodegradation and water uptake, making it suitable for applications requiring controlled scaffold resorption. These findings demonstrate the potential of alkali-treated biosilica/marine collagen reinforced PLA biocomposites for biodegradable bone tissue engineering applications.