Hollow silica reinforced magnesium nanocomposites with enhanced mechanical and biological properties with computational modeling analysis for mandibular reconstruction

Abstract

The present study investigates Mg-SiO₂ nanocomposites as biodegradable implants for orthopedic and maxillofacial applications. The effect of presence and progressive addition of hollow silica nanoparticles (0.5, 1, and 1.5) vol.% on the microstructural, mechanical, degradation, and biocompatibility response of pure Mg were investigated. Results suggest that the increased addition of hollow silica nanoparticles resulted in a progressive increase in yield strength and ultimate compressive strength with Mg-1.5 vol.% SiO₂ exhibiting superior enhancement. The response of Mg-SiO₂ nanocomposites under the influence of Hanks' balanced salt solution revealed that the synthesized composites revealed lower corrosion rates, indicating rapid dynamic passivation when compared with pure Mg. Furthermore, cell adhesion and proliferation of osteoblast cells were noticeably higher than pure Mg with the addition of 1 vol.% SiO₂ nanoparticle. The biocompatibility and the in vitro biodegradation of the Mg-SiO₂ nanocomposites were influenced by the SiO₂ content in pure Mg with Mg-0.5 vol.% SiO₂ nanocomposite exhibiting the best corrosion resistance and biocompatibility when compared with other nanocomposites. Enhancement in mechanical, corrosion, and biocompatibility characteristics of Mg-SiO₂ nanocomposites developed in this study are also compared with properties of other metallic biomaterials used in alloplastic mandibular reconstruction in a computational model.

Fig. 1

X-ray diffractograms of pure Mg and Mg-SiO₂ nanocomposites taken along the longitudinal direction of hot extruded samples. X, Y, Z represent 2θ = 32°, 34°, and 36° corresponding to (10–10) prism, (0002) basal, and (10–11) pyramidal planes, respectively

Fig. 2

The immersion response of the synthesized samples. a Calculated corrosion rates based on weight loss and b pH measurements from immersion testing

Fig. 3

Scanning electron microscope images of a pure Mg, b Mg-0.5 SiO₂, c Mg-1.0 SiO₂, and d Mg-1.5 SiO₂ nanocomposites after 7 days of immersion (red arrows indicating the corroded and non-corroded areas). Magnification, ×75. Scale bars are 200 μm

Fig. 4. Cytotoxicity in vitro for pure Mg and Mg-SiO₂ nanocomposites.

a Remaining cellular activity of and b relative cytotoxicity of MC3T3-E1 cells upon exposure to sample discs, as measured by MTS assay and LDH, respectively

Fig. 5

LIVE/DEAD staining of primary MC3T3-E1 cells cultured on samples for a Day 1, b Day 3, c Day 5, respectively, and d Percentage of living cells. Viable cells are labeled in green, the nucleus of live cells (blue), dead cells (red) and merge images of live and dead cells. d Percentage of living cells. Magnification: ×10 and scale bar are 200 µm

Fig. 6

Scanning microscope images of MC3T3-E1 cultured on Mg-SiO₂ nanocomposite samples for a Day 1, b Day 3, and c Day 7. Arrows show the cell attachment. Scale bars are 400 µm

Fig. 7

Von Misses stress values (MPa): a Pure magnesium, b Mg/1 SiO₂, c stress concentration areas. Magnitude of displacement: d Pure magnesium, € Mg/1 SiO₂, f Stress concentration areas

Fig. 8

Von Misses stress values of mandible (MPa): a Pure magnesium, b Mg/1 SiO₂, c stress concentration areas. Magnitude of displacement of mandible: d pure magnesium, e Mg/1 SiO₂, f stress concentration areas