Nanofiber/hydrogel composite scaffolds based on alginate sulfate and extracellular matrix for cartilage tissue engineering applications

In this study, a three-layer composite scaffold was fabricated based on co-electrospun polycaprolactone/gelatin (PCL/GT) and polyvinyl alcohol/gelatin sacrificial nanofiber, alginate/alginate sulfate hydrogel and decellularized extracellular matrix powder. The novelty of this study is the fabrication of co-electrospun PCL/GT and polyvinyl alcohol nanofibers, which are modified by the sacrificial agent method, alginate/alginate-sulfate hydrogels, and DECM powder as growth factors with the aim of cell infiltration. Comparing the results of the microscopy images of the co-electrospun nanofibers before and after the washing process revealed that the distance between nanofibers increased from 2 ± 0.3–8 ± 0.1 µm. Furthermore, an increase in the porosity of prepared nanofibers by the washing process was observed. In addition, cell morphology studies showed that after 7 days, the cells could penetrate the underlay of nanofibers. Decellularized extracellular matrix powder in a hydrogel medium improved cell adhesion. The scaffold's porosity was tested to evaluate the ability of the cells to penetrate. The results showed that the percentage of porosity in optimized nanofiber is 94.4 ± 1.4%, which increased by 14% compared to PCL/GT with the conventional electrospinning method. Moreover, by preparing the optimal multi-layer composite, the porosity percentage was about 93.3 ± 1%. Finally, to investigate cell infiltration, cell seeding was performed on the optimal multi-layer composite for 7 and 14 days. H&E and DAPI staining analysis demonstrated that the cell penetration process through the optimal nanofiber layer was successful.