Alendronate crosslinked chitosan/polycaprolactone scaffold for bone defects repairing

Bone tissue engineering aims to develop scaffolds that can support bone regeneration in critical-sized defects. Current scaffolds often lack the ability to sustain drug release or promote osteogenic differentiation effectively. While chitosan and polycaprolactone are commonly used in scaffold fabrication, their osteogenic potential remains limited. Alendronate is known to influence bone formation but is typically administered systemically, which limits its localized efficacy. Prior research has shown that genipin-crosslinked scaffolds can improve mechanical properties, but the integration of alendronate into such systems has not been fully explored. This gap motivated researchers to investigate whether alendronate could be anchored within a chitosan/polycaprolactone scaffold to create a sustained release system. The study aimed to address whether such a scaffold could enhance osteogenic differentiation and bone regeneration in vivo. No prior work had resolved the combined effects of alendronate and crosslinking on stem cell behavior. The research also aimed to explore the molecular pathways involved in this process.

The study aimed to assess the osteogenic potential of an alendronate-loaded chitosan/polycaprolactone scaffold in promoting new bone formation. The researchers focused on whether crosslinking alendronate into the scaffold could improve its sustained release and biological activity. They sought to determine if the scaffold could enhance ectomesenchymal stem cell differentiation into bone-forming cells. The motivation stemmed from the need for a low-cost, efficient delivery system for bone repair. The study also aimed to identify the molecular mechanisms underlying the observed osteogenic effects. By evaluating both in vitro and in vivo outcomes, the researchers aimed to validate the scaffold’s regenerative capacity. This work was driven by the limitations of current scaffolds in promoting localized drug delivery and bone regeneration. The study aimed to provide a novel strategy for bone defect repair.

The researchers fabricated a chitosan/polycaprolactone scaffold and anchored alendronate using genipin as a crosslinking agent. They tested the scaffold’s ability to sustain alendronate release in vitro. Ectomesenchymal stem cells were cultured on the scaffold to assess osteogenic differentiation. Gene and protein expression levels were analyzed to identify molecular changes. The scaffold was implanted into critical-sized calvarial defects in rats to evaluate bone regeneration. Micro-computed tomography was used to assess new bone formation quantitatively. Histological analysis was performed to confirm the presence of mature bone tissue. The study combined material science techniques with biological assays to evaluate the scaffold’s performance.

The alendronate-loaded scaffold significantly enhanced ectomesenchymal stem cell osteogenic differentiation in vitro. Bone morphogenetic protein 2, interleukin 10, and laminin expression were upregulated in cells cultured on the scaffold. The scaffold also activated the yes-associated protein signaling pathway, which is crucial for osteogenesis. Transglutaminase levels increased, indicating pathway activation. In vivo, the scaffold accelerated new bone formation in rat calvarial defects compared to controls. Micro-computed tomography showed increased bone volume and density in treated animals. Histology confirmed the presence of mature bone tissue at the defect site. These findings suggest the scaffold’s potential as a bone repair strategy.

The study demonstrated that the alendronate-loaded scaffold promoted osteogenic differentiation of ectomesenchymal stem cells through multiple mechanisms. The scaffold’s crosslinking with genipin allowed sustained alendronate release, which enhanced bone formation. Activation of the yes-associated protein pathway and upregulation of key osteogenic markers were observed. In vivo, the scaffold accelerated new bone formation in critical-sized defects. The researchers propose that this strategy could serve as an efficient delivery system for bone repair. The findings suggest that combining alendronate with a crosslinked scaffold improves regenerative outcomes. The study highlights the scaffold’s potential as a low-cost, effective solution for bone defect repair. These results align with the authors’ hypothesis that the scaffold could enhance osteogenic differentiation and bone regeneration.