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  • Development and production of 3D-printed composite scaffolds enriched with Beeswax for bone tissue regeneration
    Publication . Francisco, Martinho Jorge ; Moreira, André Ferreira; Correia, Ilídio Joaquim Sobreira; Cabral, Cátia Solange Duarte
    The regeneration of bone defects caused by trauma or disease is a significant challenge in modern medicine. Conventional therapeutic approaches like bone grafting (including autologous, allogeneic, and xenogeneic grafts), are widely used but have limitations such as donor scarcity, development of immune reactions, and risks of disease transmission, such as hepatitis, acquired immunodeficiency syndrome, bacterial infections, and bovine spongiform encephalopathy commonly known as “mad cow disease”. Bone tissue engineering has emerged as a promising alternative, focusing on developing bioactive scaffolds that mimic the native structure of bone. To this end, various therapeutic solutions under development aim to replicate the characteristics of native bone, namely the inorganic phase (i.e., calcium phosphate in the form of hydroxyapatite) and the organic phase (e.g., collagen type I, bone cells, and non-collagenous proteins), to support the natural bone healing process. This study aimed to attain the production of 3D scaffolds displaying suitable properties for bone tissue engineering, using a novel composite mixture comprising tricalcium phosphate (TCP), hydroxyapatite (HAp), sodium alginate (SA), beeswax (BW), and thymol (TM). The scaffolds were fabricated through a rapid prototyping technique, using the Fab@Home 3D-Plotter extruder via a top-down approach. The results demonstrated that the 3D-printed scaffolds exhibited well-defined structural and morphological features, with a porosity suitable for cell attachment and growth. Furthermore, scaffolds containing BW and TM showed rougher surfaces, which are more favorable for cell adhesion. The mechanical properties of the scaffolds, including compressive strength and Young’s modulus, were within the range required for bone regeneration. Otherwise, biological assays showed that the scaffolds were cytocompatible and were able to support human osteoblast cell adhesion and proliferation. In addition, the scaffolds containing TM demonstrated significant antibacterial activity, against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, making them an attractive option for preventing infections in bone healing applications. In conclusion, this study allowed the successful production of novel 3D-printed scaffolds composed of TCP, HAp, SA, BW, and TM. Compared to previous work, the addition of BW resulted in structures with improved mechanical properties, especially in humid conditions. In addition, BW also allowed the optimization of various physicochemical properties such as hydrophobicity and surface roughness, favoring cell growth. On the other hand, the incorporation of TM demonstrates the potential of this phenolic compound for application in bone regeneration, as a viable alternative to conventional antibiotic-based methods to prevent the establishment of bacterial infections and biofilm development. In this way, the results show that the scaffolds produced, incorporating materials of natural origin, could be highly effective for future clinical applications in bone tissue regeneration.
    2024-10-31Master thesis Embargoed access Show more