Surface Functionalization of Three Dimensional-Printed Polycaprolactone-Bioactive Glass Scaffolds by Grafting GelMA Under UV Irradiation

Abstract

In this study, bioactive glass nanoparticles (BGNPs) with an average diameter of less than 10 nm were synthesized using a sol-gel method and then characterized by transmission electron microscopy (TEM), differential scanning calorimetric (DSC), Fourier transforms infrared spectroscopy (FTIR), and x-ray spectroscopy (XRD). Afterward, three dimensional (3D)-printed polycaprolactone (PCL) scaffolds along with fused deposition modeling (FDM) were incorporated with BGNPs, and the surface of the composite constructs was then functionalized by coating with the gelatin methacryloyl (GelMA) under UV irradiation. Field emission scanning electron microscopy micrographs demonstrated the interconnected porous microstructure with an average pore diameter of 260 µm and homogeneous distribution of BGNPs. Therefore, no noticeable shrinkage was observed in 3D-printed scaffolds compared with the computer-designed file. Besides, the surface was uniformly covered by GelMA, and no effect of surface modification was observed on the microstructure while surface roughness increased. The addition of the BGNPs the to PCL scaffolds showed a slight change in pore size and porosity; however, it increased surface roughness. According to mechanical analysis, the compression strength of the scaffolds was increased by the BGNPs addition and surface modification. Also, a reduction was observed in the absorption capacity and biodegradation of scaffolds in phosphate-buffered saline media after the incorporation of BGNPs, while the presence of the GelMA layer increased the swelling potential and stability of the composite matrixes. Moreover, the capability of inducing bio-mineralization of hydroxyapatite-like layers, as a function of BGNPs content, was proven by FE-SEM micrographs, EDX spectra, and x-ray diffraction spectra (XRD) after soaking the obtained samples in concentrated simulated body fluid. A higher potential of the modified constructs to interact with the aqueous media led to better precipitation of minerals. According to in-vitro assays, the modified scaffolds can provide a suitable surface for the attachment and spreading of the bone marrow mesenchymal stem cells (BMSCs). Furthermore, the number of the proliferated cells confirms the biocompatibility of the scaffolds, especially after a modification process. Cell differentiation was verified by alkaline phosphatase activity as well as the expression of osteogenic genes such as osteocalcin and osteopontin. Accordingly, the scaffolds showed an initial potential for reconstruction of the injured bone.

Recent Advances, Challenges and Future Opportunities for the Use of 3D Bioprinting in Large Bone Defect Treatment

“…Recently, 3D bio-printing is introduced as a novel scaffold fabrication method and has provided numerous capabilities compared to the traditional methods such as a lower rate of residual organic solvents which decreases the harmful effects of these chemical solvents on the cell's survival and interactions, or scaffold designing before printing which leads to personalization [131,132]. Also, it is possible to build complex structures with/without cells [133].…”

Bone Tissue Engineering Scaffolds: Function of Multi‐Material Hierarchically Structured Scaffolds

“…[ 54 ] In addition to hydrolysis of the polymer, proteins, biomolecules, growth factors, and peptides bound to the polymer surface are critical to initiate a bone healing cascade. [ 55 ] Table 3 highlights the effects of using secondary phases/polymers to functionalize polymer scaffolds. Further, these bioactive polymers can be used as carriers of growth factors and biomolecules to aid bone healing.…”

Bioactive Inks Development for Osteochondral Tissue Engineering: A Mini-Review

“…Additionally, stimulating osteogenic differentiation is the most crucial feature arising from BG in the ink composition. Ghorbani and coworkers synthesized PCL/BG ink to fabricate scaffolds with the FDM method [ 80 ]. The effects of BG addition were investigated on both mechanical and biological sides.…”