Strontium-Substituted Hydroxyapatite-Gelatin Biomimetic Scaffolds Modulate Bone Cell Response

Current treatments for excessive bone resorption remain limited. Strontium has been proposed as a potential therapeutic agent due to its role in bone remodeling. However, the mechanisms by which strontium affects bone cells are still under investigation. Biomimetic scaffolds offer a promising platform for localized drug delivery. Prior research has shown that hydroxyapatite-based scaffolds can support bone regeneration. Yet, the impact of strontium substitution in these scaffolds on bone cell behavior is unclear. This gap motivated the exploration of strontium-substituted hydroxyapatite scaffolds. Such studies could advance the design of scaffolds for bone regeneration therapies.

This study aims to evaluate the effect of strontium-substituted hydroxyapatite scaffolds on bone cell response. The specific problem addressed is the need for controlled strontium delivery in bone resorption sites. The motivation stems from the potential of strontium to modulate osteoblast and osteoclast activity. The authors propose that incorporating strontium into hydroxyapatite scaffolds may enhance bone regeneration. By comparing strontium-substituted and pure hydroxyapatite scaffolds, the study investigates cell behavior differences. The goal is to determine whether these scaffolds can sustainably release strontium and influence bone cells. This could lead to improved biomaterials for localized strontium delivery in bone repair applications. The study's findings may inform the design of next-generation bone scaffolds.

The researchers prepared 3D gelatin scaffolds with strontium-substituted hydroxyapatite (SrHA) or pure hydroxyapatite (HA). Freeze-drying was used to create porous scaffolds with approximately 30% HA content. Scaffold properties such as porosity, pore interconnectivity, and mechanical strength were analyzed. Reinforcement was achieved by adding more gelatin to the scaffolds. The effect of reinforcement on pore size and water uptake was measured. Strontium release was tested in phosphate-buffered saline over 14 days. Cell culture experiments involved coculturing osteoblasts and osteoclasts on the scaffolds. Cell viability, activity, and differentiation were assessed using standard biological assays.

Scaffolds containing SrHA showed sustained strontium release, with only 14% released after 14 days. Reinforced scaffolds released 18% of their strontium content under the same conditions. The scaffolds exhibited high open porosity and full pore interconnectivity. Reinforcement slightly reduced pore size but did not affect interconnectivity. Reinforced scaffolds had lower water uptake and higher mechanical strength. Osteoblasts cultured on SrHA scaffolds showed increased viability and activity. Osteoclastogenesis and differentiation were significantly inhibited on SrHA scaffolds. These findings suggest that SrHA scaffolds may modulate bone cell behavior in a beneficial way.

The authors propose that SrHA scaffolds can modulate bone cell responses in a favorable manner. Sustained strontium release from these scaffolds was observed over a two-week period. Osteoblast viability and activity were enhanced on SrHA scaffolds compared to HA scaffolds. In contrast, osteoclast differentiation was inhibited on SrHA scaffolds. These results suggest that SrHA scaffolds may be useful in treating excessive bone resorption. The mechanical and structural properties of the scaffolds were suitable for bone tissue engineering. The study does not claim that SrHA scaffolds are essential for all bone regeneration applications. Further research is needed to confirm the clinical applicability of these findings.