Gelatın nanoparticle loaded polycaprolactone-nanohydroxyapatite functionally graded scaffolds

Official URL: https://risc01.sabanciuniv.edu/record=b3400649

Bone fractures represent a common medical challenge, necessitating innovative approaches for effective bone tissue regeneration. This thesis explores the potential of controlled bone morphogenetic protein-2 (BMP-2) release from functionally graded (FG) vs. uniform scaffolds made of Polycaprolactone (PCL) and Nanohydroxyapatite (HA) incorporating gelatin nanoparticles. The scaffolds were fabricated using a combination of the earlier proposed Non-Solvent-Induced Phase Separation (NIPS) method and 3D printing and therefore display multi-scale porosity and spatially varying macropores mimicking natural bone tissue. Gelatin nanoparticles (GNP) were created through a two-step desolvation method, and BMP-2 was encapsulated into these nanoparticles using a diffusion method. The incorporation of BMP-2 encapsulated gelatin nanoparticles into PCL-HA scaffolds of uniform and FGSs was achieved through adsorption. Of particular significance, this study investigates the effect of morphology and BMP-2-gelatin nanoparticle loading on biological and release performance of uniform and functionally graded scaffolds (FGSs). The macro porosity gradient and internal micro-porosity was analysed using micro-computed tomography (micro-CT). Tensile tests using universal tensile machine (UTM) were conducted on both uniform and FGSs to assess their mechanical strength. The variation in macro-scale porosity gradient of multi-scale porous scaffolds and its influence on in-vitro performance and release mechanism constitute the primary focus of this research and were analysed using phalloidin and DAPI staining and alkaline phosphatase activity (ALP) assays as well as enzyme linked immunosorbent assay (ELISA) and confocal microscopy. Scanning electron microscopy (SEM) was conducted to visualize the GNP structure and microstructure of scaffolds. The results underscore the viability of fabricating scaffolds via NIPS-based 3D printing and loading them via BMP-2 GNP demonstrating the potential for sustained release of BMP-2 encapsulated gelatin nanoparticles in 3D scaffolds with gradient and multi-scale porosity. The findings contribute to the understanding of how porosity gradients influence the in-vitro performance of these scaffolds, providing valuable insights for the design and optimization of tissue engineering constructs.