Development of PMMA Monolith Impregnation with Hydroxyapatite Nanoparticles for Bone Regeneration

Abstract

Introduction: Bone regeneration in maxillofacial and orthopedic applications often requires biomaterials that mimic the structural and functional properties of natural bone. Polymethyl methacrylate (PMMA) is widely used in dentistry and orthopedics due to its biocompatibility and mechanical stability, while hydroxyapatite (HAp) offers excellent osteoconductive properties. However, HAp alone is brittle, limiting its use as a scaffold material. Incorporating HAp nanoparticles into a PMMA monolith may overcome these limitations and provide an effective scaffold for hard tissue regeneration.

Objectives: The study aimed to develop and characterize hydroxyapatite-infused PMMA monoliths and evaluate their morphology, elemental composition, and mechanical properties to determine their potential for bone regeneration applications..

Methods: PMMA (Mw 15,000) was dissolved in an ethanol–water mixture and combined with hydroxyapatite solution prepared via precipitation. The mixture was subjected to phase separation and freeze-drying to form monoliths. Morphological features were analyzed using field emission scanning electron microscopy (FE-SEM), elemental composition was confirmed by energy dispersive spectroscopy (EDS) and elemental mapping, and compressive strength was measured using a universal testing machine following ASTM standards.

Results: FE-SEM analysis revealed highly porous structures with visible impregnation of hydroxyapatite particles within the PMMA matrix. EDS confirmed the presence of calcium and phosphorus, validating the successful infusion of HAp. Elemental mapping further demonstrated the distribution of these bioactive elements. Mechanical testing showed that the PMMA–HAp monoliths exhibited compressive strength up to 3 kN, indicating adequate stability for biomedical applications.

Conclusion: Hydroxyapatite-infused PMMA monoliths demonstrated favorable porosity, bioactive elemental composition, and sufficient compressive strength. These findings suggest that the fabricated composite scaffolds overcome the brittleness of HAp while retaining osteoconductive potential, making them a promising candidate for hard tissue regeneration in dental and orthopedic applications..