Development of a custom-made 3D printed bone substitute for critical-size bone defect repair

Abukhzaam, Hanan Abdusalam Salim (2024) Development of a custom-made 3D printed bone substitute for critical-size bone defect repair. PhD thesis, University of Glasgow.

Abstract

Introduction: The reconstruction of critical-size bone defects remains challenging, with autogenous bone grafting still considered the gold standard treatment despite limitations such as shortage of supply and donor site morbidity. Bone tissue engineering holds much promise to develop new bone substitutes, which can offer safety, cost-effectiveness, and efficacy.

Aims and objectives: This study aims to validate the effectiveness of a bioengineered 3D-printed scaffold with controllable micro-architecture, made from the bioabsorbable polymer polycaprolactone (PCL) that has been functionalised with plasma polymerised poly (ethyl acrylate) (pPEA), Fibronectin (FN) and Bone Morphogenic Protein (BMP), for bone repair.

Materials and Methods: The surface of scaffold was characterized using various techniques, including Atomic Force Microscopy (AFM), static water contact angle measurements (WCA), X-ray Photoelectron Spectroscopy (XPS), and quantification of protein adsorbed using bicinchoninic acid and Enzyme-Linked immunosorbent assay (ELISA). The viability of MSCs on the scaffold was assessed using fluorescent staining and alamarBlue assays. Furthermore, Quantitative Polymerase Chain Reaction (qPCR), von Kossa and Alizarin Red stains were conducted to assess the osteogenic capacity of the scaffolds. To explore the possibility of enhancing differentiation, nanovibrational stimulation was utilized to pre-condition the MSCs for osteogenesis prior to seeding them on the scaffold.

Results: The functionalization of PCL with PEA and FN significantly improved its hydrophilicity, leading to a substantial increase in the adsorption of FN and BMPs on the coated scaffold compared to the uncoated PCL scaffolds. The coated scaffolds exhibited significantly higher bioactivity, with a significantly larger number of cells attached and displaying elevated metabolic activity compared to the control group. Moreover, the osteogenic activity of the coated scaffold was validated, as demonstrated by a notable upregulation of osteogenic markers both with direct seeding of native MSCs onto the scaffolds and, notably more so, with MSC pre-conditioning using nanovibrational stimulation.

Conclusion: The functionalized PCL surface (PEA+FN+BMPs) demonstrated promising biocompatibility and osteogenic potential in vitro. Additionally, cell preconditioning emerged as a valuable step in a combined cell-device regenerative therapy approach. These findings suggest that the bioengineered scaffold holds considerable promise as a viable alternative for critical-size bone defect repair.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Supported by funding from the Libyan embassy.
• Subjects: Q Science > QR Microbiology; R Medicine > R Medicine (General)
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Supervisor's Name: Busuttil Naudi, Dr. Kurt, Ayoub, Professor Ashraf and Dalby, Professor Matthew
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84484
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 09 Aug 2024 15:21
• Last Modified: 09 Aug 2024 15:27
• Thesis DOI: 10.5525/gla.thesis.84484
• URI: https://theses.gla.ac.uk/id/eprint/84484