The effect of increasing the pore size of nanofibrous scaffolds on the osteogenic cell culture using a combination of sacrificial agent electrospinning and ultrasonication

Abstract

One of the major problems associated with the electrospun scaffolds is their small pore size, which limits the cellular infiltration for bone tissue engineering. In this study, the effect of increasing the pore size on cellular infiltration was studied in poly/nanohydroxyapatite electrospun scaffolds, which were modified using ultrasonication, co-electrospinning with poly (ethylene oxide), and a combination of both. Ultrasonic process was optimized by central composite design. The ultrasonic output power and time of the process were considered as the effective parameters. The pore size of the scaffolds was evaluated by scanning electron microscope. The optimum conditions, according to the pore area and mechanical properties of the scaffolds were selected, and finally the groups that had the highest pore size and mechanical strength were selected for the combined method. Increasing the pore size enhanced the cellular proliferation, extension and infiltration, as well as the osteodifferentiation of stem cells. At the optimum condition, the average cellular infiltration was 36.51 µm compared to the control group with no cellular infiltration. In addition, alkaline phosphatase activity and the expression of osteocalcin and collagen I (COL I) were, respectively, 1.86, 2.54, and 2.16 fold compared to the control group on day 14. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1887-1899, 2017.

The effect of modified electrospun PCL‐nHA‐nZnO scaffolds on osteogenesis and angiogenesis

“…FTIR characterization was carried out on different scaffold types, including PCL, PCL‐based before and after removal of PEO (Figure ), and PCL‐based with ZnO (Figure ). The peaks at 841, 1972, 2,695, 2,741, 2,886, and 3,446 cm −1 (associated with PEO fibers) did not appear for PCL‐based scaffolds, where PEO fibers have been removed (Aghajanpoor et al, ). According to the FTIR spectra of PCL‐based scaffolds with or without n‐ZnO (Figure ), the characteristic bands such as CO at 1170, CO at 1730, and CH at 2948 and 733 cm −1 were related to PCL, and PO 4 3− at 563, 604, 960, 1,047, and 1,108 cm −1 were related to n‐HA in the fibers (Bužarovska, ; Cengiz, Gokce, Yildiz, Aktas, & Calimli, ).…”

“…The analyzed results using Image J software are reported in Table . The effect of modified pore size on cell infiltration is clear (Aghajanpoor et al, ), and also the presence of n‐ZnO does not have any significant effect on the cell infiltration.…”

“…Surface morphology of the fabricated scaffolds coated with gold was investigated by scanning electron microscopy (SEM; Hitachi, S‐4160) at an accelerating voltage of 20 kV. Distributions of the fiber diameter and pore size were estimated from the SEM images using Image J software (Aghajanpoor et al, ).…”

“…Bone tissue engineering is a suitable approach for bone healing, and one of its major challenges is the treatment of large bone defects. Electrospun scaffolds with high porosity provide a similar environment to the natural extracellular matrix; however, they suffer from some drawbacks, such as small pore size for cell penetration and migration (Aghajanpoor et al, ; Bhowmick et al, ).…”

“…Microstructure of the scaffolds has high impact on the cell infiltration, differentiation, cell–cell contact, and vascularization (Phadke, Hwang, Hee Kim, et al, ). In our previous work (Aghajanpoor et al, ), we optimized the pore size of electrospun polycaprolactone (PCL)‐nanohydroxyapatite (nHA) scaffolds using a combination of a sacrificial agent (polyethylene oxide [PEO]) and ultrasonication, for bone tissue engineering purposes. The modified scaffolds showed osteogenesis promotion, compared to the control ones.…”