PEI-modified diatomite/chitosan composites as bone tissue engineering scaffold for sustained release of BMP-2

Abstract

The bone healing defects resulting from bone disease remain a significant clinical challenge. The bone tissue engineering scaffolds combined with osteoinductive compounds represent an effective approach to overcome this challenge. In this study, a novel chitosan-based scaffold was prepared by incorporating modified natural diatomite (DE) as filler and adsorption element. Specifically, modified-diatomite (MDE) was synthesized by grafting polyethyleneimine (PEI) on the surface of diatomite via hydroxyl groups. The physicochemical characteristics of MDE, including chemical composition, zeta potential, and adsorption behavior, were investigated successively. Further, the mechanical strength, drug release, cytotoxicity and osteogenic activity analyses were carried out for the scaffold material. The FTIR and zeta potential analyses exhibited that the amino groups (–NH₂) were grafted on MDE, and the surface potential of diatomite altered from −24 mV to 55 mV. Subsequently, the protein adsorption capacity and cytocompatibility of MDE were observed to be improved as compared to DE. The compressive strength was observed to be enhanced due to the addition of MDE. Besides, the composite scaffold loaded with rhBMP-2 demonstrated a more positive impact on proliferation and osteogenic differentiation of the bone mesenchymal stem cells, thus, indicating an optimal bone regeneration capacity. The findings obtained in this study reveal that the MDE-rhBMP-2/CS composite scaffold can be potentially used to promote the bone tissue regeneration.

Keywords:

• Diatomite
• surface potential
• protein adsorption
• composite scaffold
• drug delivery

Acknowledgments

The authors would like to express their gratitude to EditSprings (https://www.editsprings.com/) for the expert linguistic services provided.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported by Scientific and Technological Innovation Programs of Higher Education Institutions (2019L0432 and 2020L0217) in Shanxi, Research Fund of Shanxi Medical University School and Hospital of Stomatology (KY201806) and Follow-up to the Fourth National Oral Health Epidemiological Survey (201502002).