Monetite addition into gelatin based freeze-dried scaffolds for improved mechanical and osteogenic properties

This study was aimed at fabricating monetite nanoparticles impregnated gelatin-based composite scaffold to improve the chemical, mechanical and osteogenic properties. Scaffolds were fabricated using a freeze-drying technique of the slurry containing a varying proportion of gelatin and monetite. The lyophilized scaffolds were cross-linked with 0.25 wt% glutaraldehyde solution to obtain a three-dimensional (3D) interconnected porous microstructure with improved mechanical strength and stability in a physiological environment. The fabricated scaffolds possessed >80% porosity having 3D interconnected pore size distribution varying between 65 and 270 mu m as evident from field emission scanning electron microscopy analysis. The average pore size of the prepared scaffold decreased with monetite addition as reflected in values of 210 mu m for pure gelatin GM(0) scaffold and 118 mu m registered by GM(20) scaffold. On increase in monetite content up to 20 wt% of total polymer concentration, compressive strength of the prepared scaffolds was increased from 0.92 MPa in pure gelatin-based GM(0) to 2.43 MPa in GM(20). Up to 20 wt% of monetite reinforced composite scaffolds exhibited higher bioactivity as compared to that observed in pure gelatin-based GM(0) scaffold. Simulated body fluid (SBF) study and alizarin red assays confirmed higher bio-mineralization ability of GM(20) as compared to that exhibited by GM(0). Human preosteoblast cells (MG-63) revealed higher degree of filopodia and lamellipodia extensions and excellent spreading behavior to anchor with GM(20) matrix as compared to that onto GM(0) and GM(10). MTT assay and alkaline phosphatase staining study indicated that MG-63 cells found a more conducive environment to proliferate and subsequently differentiate into osteoblast lineage when exposed to GM(20) scaffolds rather than to GM(0) and GM(10). This study revealed that up to 20 wt% monetite addition in gelatin could improve the performance of prepared scaffolds and serve as an efficient candidate to repair and regenerate bone tissues at musculoskeletal defect sites.