3D printed polycaprolactone scaffold incorporated with tragacanth gum/bioactive glass and cellulose nanocrystals for bone tissue engineering

Biomimetic organic-inorganic nanocomposite scaffolds hold tremendous potential to accelerate bone regeneration due to their ability to provide excellent structural and biological cues. Therefore, we employed a 3D-printed polycaprolactone host component as a mechanical support that was filled with a tragacanth gum-45S5 bioactive glass-cellulose nanocrystal guest component. The designed host-guest scaffolds were evaluated via physical, chemical, mechanical, and biological properties. Owing to the successful integration between host and guest components, the scaffolds showed enhanced physical and swelling properties (approximately 100 %) for nutrient transfer and cell proliferation. Furthermore, the host-guest scaffolds exhibited improved surface apatite formation and increased strength (3.35-16.55 MPa) within the ideal range for bone tissue engineering applications. It was verified in vitro that the host-guest scaffolds offer a highly desirable microenvironment for cell proliferation and attachment. Importantly, the host-guest scaffolds exhibited remarkable calcium deposition (4-56 %) and matrix formation. However, it was found that the proportion of cellulose nanocrystals can affect the properties of fabricated host-guest scaffolds. These results highlight the importance of optimizing the cellulose nanocrystal content in the scaffold composition to achieve the desired balance of properties for effective bone tissue engineering applications. The incorporation of cellulose nanocrystals at lower concentrations, particularly 3 wt%, represents a promising approach for developing biomimetic scaffolds that can enhance bone regeneration. Notably, the results of this study confirmed that incorporating cellulose nanocrystals at lower concentrations into the host-guest scaffolds is a viable strategy for fabricating a suitable biomaterial that enhances bone tissue engineering applications.