Evaluation of bone allograft processing methods: Impact on decellularization efficacy, biocompatibility and...

Bone grafting is a critical area of orthopedic and reconstructive surgery. As the global population ages, the need for effective bone grafting materials continues to rise. Autologous grafts remain the standard of care, but they come with limitations such as donor site morbidity. Allografts and xenografts offer alternatives that avoid these issues. The success of these grafts depends heavily on their physiochemical properties, which are shaped by the processing methods used. Decellularization is a key step in preparing allografts, as it aims to remove cellular components while preserving the structural and biochemical integrity of the graft. However, the impact of different decellularization methods on graft properties and their interaction with mesenchymal stem cells is not yet fully understood. No prior work has resolved the question of which decellularization method leads to the most favorable outcomes in terms of biocompatibility and stem cell functionality. That uncertainty drove the current investigation into two distinct decellularization approaches and their effects on graft performance.

This study aimed to evaluate the impact of two different decellularization methods on the properties of bone allografts. The first objective was to compare the efficacy of chemical processing and sonication-based processing in removing cellular material from the grafts. The second objective was to assess how these methods affect the grafts' surface texture and composition. The third goal was to evaluate the biocompatibility of the processed grafts by measuring their impact on mesenchymal stem cell (MSC) viability. The fourth objective was to determine how the grafts support MSC functionality, including cell adhesion, proliferation, and osteogenic differentiation. The fifth aim was to compare the performance of the two decellularization methods with commercially available allografts and xenografts. The sixth goal was to assess the effects of the extraction medium used during processing on MSC behavior. The seventh objective was to evaluate the overall osteogenic potential of the grafts by measuring alkaline phosphatase activity and mineralization. The eighth goal was to determine whether the decellularization method influences the suitability of the graft for stem cell-based therapies.

The study compared two decellularization methods: chemical processing and sonication-based processing. Each method was applied to bone allografts to produce chemically processed allografts (CPAs) and sonication-based processed allografts (SPAs). The efficacy of decellularization was assessed by measuring DNA content, a proxy for residual cellular material. Surface texture and composition were analyzed using scanning electron microscopy and biochemical assays. Biocompatibility was tested by exposing mesenchymal stem cells to the extraction medium from each graft type. MSC functionality was evaluated by reseeding the cells onto the grafts after pre-differentiation in osteogenic medium. Cell adhesion and proliferation were measured using cell counting and metabolic activity assays. Alkaline phosphatase activity and mineralization were quantified to assess osteogenic differentiation. Commercially available allografts and xenografts were included as controls for comparison. The study also examined the effects of the extraction medium on MSC viability and function. Data were collected using standardized protocols to ensure consistency across all experimental groups.

The sonication-based processed allografts (SPAs) demonstrated greater decellularization efficacy compared to the chemically processed allografts (CPAs). DNA quantification showed a 60% reduction in SPAs versus a 35% reduction in CPAs. Surface texture analysis revealed that SPAs retained a more intact extracellular matrix structure. Composition testing indicated that SPAs preserved more collagen and mineral content than CPAs. Despite the higher decellularization efficacy, SPAs induced a 15% decrease in MSC viability compared to CPAs. MSCs reseeded onto SPAs showed comparable proliferation rates to those on commercial allografts. Alkaline phosphatase activity was similar between SPAs and commercial grafts, suggesting equivalent osteogenic potential. Mineralization levels were also comparable across the groups, indicating that SPAs supported osteogenic differentiation as effectively as commercial products. Commercial Tutoplast allografts outperformed both SPAs and CPAs in terms of MSC viability and osteogenic differentiation.

The study found that sonication-based processing leads to more effective decellularization than chemical processing. However, this method also caused a slight reduction in MSC viability. Despite this, the overall performance of SPAs in supporting MSC functionality was comparable to commercial allografts. The authors suggest that the choice of decellularization method should consider both the degree of decellularization and the impact on cell viability. The results indicate that SPAs may be suitable for applications where high decellularization is required. The study also highlights the importance of evaluating grafts not only for their structural properties but also for their biological interactions with stem cells. Commercial Tutoplast allografts showed the best overall performance in terms of MSC functionality. The findings support the use of SPAs in stem cell-based therapies, provided that the viability impact is managed. The authors note that further research is needed to optimize decellularization methods for specific clinical applications. The study contributes to the understanding of how processing techniques influence graft performance in regenerative medicine.