Magnesium Hydroxide as a Versatile Nanofiller for 3D-Printed PLA Bone Scaffolds.

Polylactic acid (PLA) is widely used in bone tissue engineering due to its biocompatibility and ease of processing. However, PLA scaffolds face limitations such as slow degradation, acidic byproducts, weak biomineralization, and poor cell interactions. These challenges hinder their effectiveness for long-term bone regeneration. While prior research has shown that polymer scaffolds can support tissue growth, they often fail to meet the mechanical and biological demands of bone repair. No prior work had resolved the simultaneous improvement of degradation, mechanical strength, and cell compatibility in a single scaffold design. This gap motivated the exploration of nanofillers to enhance PLA scaffolds. Researchers have already shown that adding inorganic components can improve scaffold properties, but no study had tested magnesium hydroxide specifically for this purpose. This paper introduces a new approach to address multiple scaffold limitations using a single nanofiller. The need for a material that can neutralize acidic degradation, promote mineralization, and support cell growth led to this investigation.

This study aimed to evaluate the use of magnesium hydroxide (Mg(OH)₂) as a nanofiller in 3D-printed polylactic acid (PLA) bone scaffolds. The goal was to determine whether Mg(OH)₂ could simultaneously improve mechanical strength, degradation behavior, and biocompatibility of the scaffolds. The researchers focused on addressing the limitations of pure PLA scaffolds, including slow degradation and poor cell response. They hypothesized that Mg(OH)₂ could neutralize acidic byproducts of PLA, accelerate degradation, and support cell growth. The motivation for this study was to develop a multifunctional scaffold that could meet the mechanical and biological requirements of bone tissue engineering. The approach involved using fused deposition modeling (FDM) to fabricate composite scaffolds with varying Mg(OH)₂ concentrations. By testing mechanical, degradation, and biological properties, the researchers sought to validate the potential of Mg(OH)₂ as a versatile nanofiller in tissue engineering applications.

The researchers prepared PLA/Mg(OH)₂ composite scaffolds using fused deposition modeling (FDM) 3D printing. They varied the Mg(OH)₂ concentration from 0 to 20 wt% to assess its effects on scaffold properties. Mechanical tests were conducted to measure tensile and compressive strengths of the scaffolds. Degradation behavior was evaluated by immersing the scaffolds in phosphate buffered solution (PBS) and measuring weight loss over 28 days. Simulated body fluid (SBF) immersion was used to assess biomineralization by observing apatite deposition on scaffold surfaces. Cell culture experiments with bone marrow mesenchymal stem cells (BMSCs) were performed to evaluate cell adhesion, proliferation, and osteogenic differentiation. The release of Mg²⁺ ions from the scaffolds was monitored over time to determine its impact on cell behavior. The study combined material characterization with biological testing to validate the performance of Mg(OH)₂ as a nanofiller in 3D-printed scaffolds.

The addition of 5 wt% Mg(OH)₂ increased the tensile strength of the scaffolds by 20.50% and compressive strength by 63.97%. The 20 wt% Mg(OH)₂ composite showed a weight loss of 15.40% after 28 days in PBS, compared to 0.15% for pure PLA. Mg(OH)₂ released Mg²⁺ ions continuously for more than 28 days. The alkaline degradation products of Mg(OH)₂ neutralized the acidic PLA byproducts, accelerating scaffold degradation. SBF immersion revealed enhanced apatite deposition on composite scaffolds, indicating improved biomineralization. Cell culture results showed that 5 wt% Mg(OH)₂ significantly improved BMSC adhesion, proliferation, and osteogenic differentiation. The Mg²⁺ release from the scaffolds contributed to better cell responses. These findings suggest that Mg(OH)₂ can simultaneously improve mechanical, degradation, and biological properties of PLA scaffolds.

The authors concluded that Mg(OH)₂ is a versatile nanofiller for 3D-printed PLA bone scaffolds. The addition of Mg(OH)₂ improved mechanical strength, accelerated degradation, and enhanced biomineralization. The alkaline degradation products of Mg(OH)₂ neutralized acidic PLA byproducts, promoting faster scaffold breakdown. Mg²⁺ release from the scaffolds supported better cell adhesion, proliferation, and osteogenic differentiation. The study demonstrated that Mg(OH)₂ can address multiple limitations of pure PLA scaffolds in a single modification. The results suggest that Mg(OH)₂ has promising applications in tissue engineering for bone repair. The authors propose that this approach could be extended to other polymer scaffolds to improve their performance. The findings highlight the potential of Mg(OH)₂ to enhance scaffold functionality without compromising biocompatibility.