A 3D-bioprinted alginate-MgP scaffold for superior regeneration of calvarial bone defects in a rat model

Abstract

While autologous transplants are the traditional standard intervention for non-healing bone defect regeneration, they carry many risks and limitations. Regenerative composite biomaterials are promising alternatives to conventional autograft and allograft implants. This study aimed to overcome these challenges by creating a novel biodegradable 3D biomaterial scaffold that mimics the structural and physiological properties of native bone. Scaffolds composed of magnesium phosphate (MgP) doped with copper oxide (CuO) in specific proportions (3, 5, or 7% [w/w]) were homogenously distributed in an alginate polymer matrix for the repair of calvarial bone defects in a rat model. The scaffolds were fabricated using a 3D bioprinting technique, and their physical properties were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, and mechanical strength assessments. The bioactivity of the scaffolds was evaluated in vitro for biomineralization and cytotoxicity, revealing high biomineralization and cell viability. Female rats were used for the in vivo experiments, and the defects were examined using microscopic and histological analysis, computed tomography imaging, as well as serum markers including osteocalcin and procollagen III. The in vivo results demonstrated high efficacy of the scaffolds in promoting bone regeneration and enhanced healing in the calvarial defect model. The incorporation of CuO not only improved the scaffolds’ mechanical properties but also exhibited angiogenic effects, fostering an environment conducive to bone healing. Our results indicated that the Alg–MgP–CuO scaffolds have great promise for bone tissue engineering applications and repair, especially with 7% (w/w) CuO doping.  

Keywords

3D bioprinting / Alginate / Bone regeneration / Copper oxide doping / Magnesium phosphate.

Funding

This research was funded by the project “Composite Bioinks for 3D Bioprinting and Their Application in Bone Tissue Engineering,” supported by the Academy of Scientific Research and Technology (ASRT) in Egypt. The authors acknowledge the financial support of the National Research Foundation (NRF) of South Africa under the SARChI Chair program (grant no. PPNT230823145247) awarded to Prof. Yahya Choonara.

Conflict of Interest

The authors declare no conflict of interest.

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