Strontium-modified chitosan/montmorillonite composites as bone tissue engineering scaffold

Highlights: • Strontium-modified chitosan/montmorillonite (Sr-C/MMT) composite was developed. • Macroporous 3D Sr-C/MMT sponge-like scaffold was fabricated by freeze-drying. • The release of Sr²⁺ from the scaffold was evaluated. • Human osteoblasts attached and proliferated on the biocompatible scaffold. • Sr-C/MMT has potential as a biomimetic template for bone tissue engineering. - Abstract: The objective of this study is to develop chitosan/montmorillonite (C/MMT) composite scaffolds based on improved properties for bone tissue engineering applications. With the freeze-drying technique, strontium (Sr²⁺) modified C/MMT composite scaffold with an interconnected porous structure was produced. X-ray diffraction, fourier transform infrared spectroscopy, thermal gravimetric analysis, and scanning electron microscopy (SEM) were employed to investigate the structural properties, surface morphology and porosity of the composite scaffold. One of the aims of this study was to document the release of Sr²⁺ from the non-modified and modified scaffolds into the cell culture medium. The biocompatibility of composite scaffolds was evaluated in cell cultures. Human osteoblasts (hOBs) were cultured, expanded and seeded on Sr²⁺-modified and non-modified C/MMT scaffolds. In-vitro cell viability and proliferation were investigated using MTT (3‑(4,5‑dimethylthiasol‑2‑yl)‑2,5‑diphenyltetrazolium bromide) assay and DNA content analysis. Live/dead cell staining assay and SEM were used for evaluating the cell-laden constructs. In-vitro studies showed that C/MMT scaffolds had no negative effects on osteoblasts. Ions present in the MMT were released into the cell culture medium, to induce osteoblast activity in the C/MMT scaffold system. Findings indicate that Sr²⁺ modification of MMT-chitosan improves scaffold properties, suggesting Sr²⁺-modified C/MMT composite may be a promising biomaterial for bone tissue engineering.