Composite Fiber Spun Mat Synthesis and In Vitro Biocompatibility for Guide Tissue Engineering

Composite scaffolds are commonly used strategies and materials employed to achieve similar analogs of bone tissue. This study aims to fabricate 10% wt polylactic acid (PLA) composite fiber scaffolds by the air-jet spinning technique (AJS) doped with 0.5 or 0.1 g of zirconium oxide nanoparticles (ZrO2) for guide bone tissue engineering. ZrO2 nanoparticles were obtained by the hydrothermal method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). SEM and fourier-transform infrared spectroscopy (FTIR) analyzed the synthesized PLA/ZrO2 fiber scaffolds. The in vitro biocompatibility and bioactivity of the PLA/ZrO2 were studied using human fetal osteoblast cells. Our results showed that the hydrothermal technique allowed ZrO2 nanoparticles to be obtained. SEM analysis showed that PLA/ZrO2 composite has a fiber diameter of 395 nm, and the FITR spectra confirmed that the scaffolds’ chemical characteristics are not affected by the synthesized technique. In vitro studies demonstrated that PLA/ZrO2 scaffolds increased cell adhesion, cellular proliferation, and biomineralization of osteoblasts. In conclusion, the PLA/ZrO2 scaffolds are bioactive, improve osteoblasts behavior, and can be used in tissue bone engineering applications.

Influence of Culture Period on Osteoblast Differentiation of Tissue-Engineered Bone Constructed by Apatite-Fiber Scaffolds Using Radial-Flow Bioreactor

With the limitation of autografts, the development of alternative treatments for bone diseases to alleviate autograft-related complications is highly demanded. In this study, a tissue-engineered bone was formed by culturing rat bone marrow cells (RBMCs) onto porous apatite-fiber scaffolds (AFSs) with three-dimensional (3D) interconnected pores using a radial-flow bioreactor (RFB). Using the optimized flow rate, the effect of different culturing periods on the development of tissue-engineered bone was investigated. The 3D cell culture using RFB was performed for 0, 1 or 2 weeks in a standard medium followed by 0, 1 or 2 weeks in a differentiation medium. Osteoblast differentiation in the tissue-engineered bone was examined by alkaline phosphatase (ALP) and osteocalcin (OC) assays. Furthermore, the tissue-engineered bone was histologically examined by hematoxylin and eosin and alizarin red S stains. We found that the ALP activity and OC content of calcified cells tended to increase with the culture period, and the differentiation of tissue-engineered bone could be controlled by varying the culture period. In addition, the employment of RFB and AFSs provided a favorable 3D environment for cell growth and differentiation. Overall, these results provide valuable insights into the design of tissue-engineered bone for clinical applications.

The effect of modifying the nanostructure of gelatin fiber scaffolds on early angiogenesis in vitro and in vivo

Early angiogenesis is one of the key challenges in tissue regeneration. Crosslinking mode and fiber diameter are critical factors to affect the adhesion and proliferation of cells. However, whether and how these two factors affect early angiogenesis remain largely unknown. To address the issue, the optimal crosslinking mode and fiber diameter of gelatin fiber membrane for early angiogenesis in vivo and in vitro were explored in this work. Compared with the post crosslinked gelatin fiber membrane with the same fiber diameter, the 700 nm diameter in situ crosslinked gelatin fiber membrane was found to have smaller roughness (230.67 ± 19 nm) and stronger hydrophilicity (54.77 ± 1.2°), which were suitable for cell growth and adhesion. Moreover, the in situ crosslinked gelatin fiber membrane with a fiber diameter of 1000 nm had significant advantages in early angiogenesis over the two with fiber diameters of 500 and 700 nm by up-regulating the expression of Ang1, VEGF, and integrin-β1. Our findings indicated that the in situ crosslinked gelatin fiber membrane with a diameter of 1000 nm might solve the problem of insufficient blood supply in the early stage of soft tissue regeneration and has broad clinical application prospects in promoting tissue regeneration.

Poly-ε-Caprolactone/Halloysite Nanotube Composites for Resorbable Scaffolds: Effect of Processing Technology on Homogeneity and Electrospinning

Polycaprolactone (PCL)/halloysite composites were prepared to compare the effect of homogenization technology on the structure and properties of the composites. Halloysite content changed from 0 to 10 vol% in six steps and homogeneity was characterized by various direct and indirect methods. The results showed that the extent of aggregation depends on technology and on halloysite content; the size and number of aggregates increase with increasing halloysite content. Melt mixing results in more homogeneous composites than the simple compression of the component powders or homogenization in solution and film casting. Homogeneity and the extent of aggregation determines all properties, including functionality. The mechanical properties of the polymer deteriorate with increasing aggregation; even stiffness depends on homogeneity. Strength and deformability decreases drastically as the number and size of aggregates increase. Not only dispersed structure, but also the physical state and crystalline structure of the polymer influence homogeneity and properties. The presence of the filler affects the preparation of electrospun fiber scaffolds as well. A part of the filler is excluded from the fibers while another part forms aggregates that complicates fiber spinning and deteriorates properties. The results indicate that spinning is easier and the quality of the fibers is better if a material homogenized previously by melt mixing is used for the production of the fibers.