Use of Gelatin as a Sacrificial Agent in Combination with Ultrasonication to Improve Cell Infiltration and Osteogenesis of Nanofibrous PCL-nHA Scaffolds for Bone Tissue Engineering

Electrospinning has been widely used to prepare nanofibrous scaffolds for bone tissue engineering. However, owing to the small pore size of electrospun scaffolds, cellular infiltration and tissue ingrowth are impossible. The use of sacrificial fibers (like poly ethylene oxide (PEO)) in combination with ultrasonication has been an appropriate way to increase the pore size of the electrospun scaffolds in our previous work. However, it is uneconomical due to the high cost of PEO. In this study, gelatin was chosen as a novel sacrificial agent in co-electrospun with polycaprolacton-nanohydroxyapatite (PCL-nHA). After electrospinnig, gelatin was washed with water, and the prepared scaffold was ultrasonicated. Morphological and structural properties of the prepared scaffolds were studied by SEM. Fourier transform infrared (FTIR) spectroscopy and water contact angle analysis were used to evaluate the removal of gelatin. According to the SEM results, the pore size of the modified scaffolds was increased 3-folds compared to the control sample. For PCL-nHA: gelatin (80:20) after the treatment, the average cell infiltration was 42.7 μm, while there was no infiltration for the control group. The modified electrospun scaffold significantly enhanced the osteogenic differentiation of hBMSCs as verified by increased ALP activity and upregulation of runt-related transcription factor 2 (RUNX2), collagen type 1 (COL1) and osteocalcin (OCN) genes. Co-electrospun PCL-nHA with gelatin as a sacrificial agent in combination with ultrasonication may be an effective, economic and controllable method to increase the pore size in electrospun scaffolds for bone tissue engineering applications.