Effects of Magnesium-Doped Hydroxyapatite Nanoparticles on Bioink Formulation for Bone Tissue Engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Nanotechnology

Background:

• Bioprinting holds promise for bone tissue engineering, utilizing nanohydroxyapatite (nHA)-based bioinks.
• The influence of nHA's physicochemical properties on bioink printability and cell behavior is not well understood.
• Developing biomimetic bioinks requires precise control over nanoparticle characteristics.

Purpose of the Study:

• To synthesize and characterize two distinct nHAs with varying properties.
• To investigate the impact of these nHAs on bioink printability and human bone marrow stromal cell (hBMSC) behavior.
• To evaluate how nHA chemistry and morphology affect osteogenic differentiation in bioprinted constructs.

Main Methods:

• Synthesis and characterization of crystalline, needle-like Mg2+-doped nHA (N-HA) and amorphous, rounded Mg2+- and CO32--doped nHA (R-HA).
• Incorporation of 1% (w/w) nHA into gelatin and GelMA bioinks for bioprinting hBMSCs.
• Assessment of bioink printability (extrudability, buildability, filament spreading).
• Evaluation of hBMSC viability, metabolic activity, and osteogenic differentiation over 21 days.

Main Results:

• Both N-HA and R-HA significantly improved the printability of GelMA-based bioinks.
• High cell viability was observed for both nHA types.
• N-HA enhanced metabolic activity under non-osteogenic conditions; R-HA boosted it with osteogenic stimulation.
• Distinct effects of nHA chemistry and morphology on osteogenic marker expression at RNA and protein levels were observed.

Conclusions:

• Physicochemical properties of nHA nanoparticles critically influence bioink performance in bone bioprinting.
• Tailoring nHA characteristics is essential for creating effective biomimetic bioinks.
• This study provides insights into optimizing nHA for enhanced bone regeneration applications.