3D-printed bioactive scaffolds with alginate hydrogel and stromal vascular fraction differentiated into osteoblasts applied to bone repair.

Abstract

Bone injuries present enormous medical challenges worldwide. Most scaffolds used in tissue engineering do not possess an appropriate combination of properties inherent to bone tissue, such as elasticity, rigidity, biocompatibility, osteoinductivity, and antimicrobial properties. In this study, we constructed a bioprinted scaffold using polycaprolactone (PCL), polyethylene glycol (PEG), and alginate cellular carrier hydrogels. This scaffold is associated with the stromal vascular fraction (SVF), a heterogeneous cell population rich in adipose-derived stem cells and contains osteogenic differentiation factors that promote bone repair. The successful construction of the PCL-PEG-based scaffold was confirmed using Fourier-transform infrared spectroscopy and X-ray diffraction, and thermal evaluation of the material showed stability above 210 °C. Flow cytometry was used to evaluate cell integration and biological activity. Studies have shown low cytotoxicity of scaffolds based on PCL-PEG 70:30 (w/w) interacting with SVF cells, with viability higher than 95%. The scaffolds based on PCL-PEG 70:30 (w/w) did not exhibit cytotoxic characteristics and did not interfere with cell proliferation. Scaffolds based on PCL-PEG 70:30 (w/w) showed favorable kinetics of interaction with the bone lesions of C57BL6J mice, accelerating the lesion closure process and facilitating the formation of new bone tissue with an area of wound closure of up to 40% compared with animals without scaffolds. In addition, tissues morphologically similar to non-injured regions and an increase in blood vessels were observed. Therefore, the developed PCL-PEG 70:30 (w/w)-based scaffold is a promising tool for bone tissue engineering applications.