Enhanced osteoinduction of electrospun scaffolds with assemblies of hematite nanoparticles as a bioactive interface

Abstract

Purpose

Electrospun scaffolds have been studied extensively for their potential use in bone tissue engineering. However, their hydrophobicity and relatively low matrix stiffness constrain their osteoinduction capacities. In the present study, we studied polymer electrospun scaffolds coated with hydrophilic hematite nanoparticles (αFeNPs) constructed using layer-by-layer (LbL) assembly to construct a bioactive interface between the scaffolds and cells, to improve the osteoinduction capacities of the scaffolds.

Materials and methods

The morphology of the αFeNPs was assessed. Surface properties of the scaffolds were tested by X-ray photoelectron spectroscopy (XPS), surface water contact angle, and in vitro protein adsorption test. The stiffness of the coating was tested using an atomic force microscope (AFM). In vitro cell assays were performed using rat adipose-derived stem cells (ADSCs).

Results

Morphology characterizations showed that αFeNPs assembled on the surface of the scaffold, where the nano assemblies improved hydrophilicity and increased surface roughness, with increased surface stiffness. Enhanced initial ADSC cell spread was found in the nano assembled groups. Significant enhancements in osteogenic differentiation, represented by enhanced alkaline phosphatase (ALP) activities, elevated expression of osteogenic marker genes, and increased mineral synthesis by the seeded ADSCs, were detected. The influencing factors were attributed to the better hydrophilicity, rougher surface topography, and harder interface stiffness. In addition, the presence of nanoparticles was believed to provide better cell adhesion sites.

Conclusion

The results suggested that the construction of a bioactive interface by LbL assembly using αFeNPs on traditional scaffolds should be a promising method for bone tissue engineering.

Keywords:

• layer-by-layer assembly
• osteogenesis
• nanotechnology
• bone tissue engineering
• surface
• αFeNPs

Supplementary material

Figure S1 Samples were prepared for attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR; NICOLET6700FT-IR, Thermo Scientific, Dallas, TX, USA) analysis.

Note: Compared with the ES control, αFe-ES showed a peak at 1,543 cm⁻¹, representing the typical stretching of -NR₂, which was caused by the nitrogen plasma treatment.

Abbreviations: αFe-ES, αFeNPs-assembled electrospun scaffold; ATR-FTIR, attenuated total reflectance Fourier transform infrared spectroscopy; ES, untreated electrospun scaffold.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (grant number 81771044 and 81800937), the Jiangsu Medical Youth Talent (grant number QNRC2016853), the Southeast University-Nanjing Medical University Cooperative Research Project (grant number 2242018K3DN16), Qing Lan Project, and the Project of the Priority Academic Program Development of Jiangsu Higher Education Institutions (grant number 2018-87).

Author contributions

Jianfei Sun and Yang Xia both conceived the project and wrote the manuscript. Jianfei Sun and Yang Xia designed the experiments. Shanshan Ma and Zibin Wang performed the fabrication and the characterization of the scaffolds. Peng Wang prepared the nanoparticles. Shanshan Ma, Yu Guo, and Zukun Yang carried out the cell culture, cell activity test, and captured the CLSM images. Liping Han performed the statistical analysis. Zibin Wang performed the TEM. All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.