چكيده به لاتين
The field of bone tissue engineering has advanced significantly, focusing on the development of biocompatible scaffolds with improved mechanical properties for load-bearing biomedical applications. This thesis aims to synthesize, optimize, and characterize ceramic/polymer composite scaffolds for use in bone tissue regeneration. The first phase explores the integration of nano-silica (SiO2) into Hydroxyapatite (HA) scaffolds to enhance mechanical strength, printability, and biocompatibility. A Design of Experiment (DOE) methodology was used to develop 13 ceramic pastes optimized for rheological properties, extrudability, and 3D printability. Characterization techniques, including amplitude and flow sweep tests, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDX), were employed. The Definitive Screening Design (DSD) identified an ideal HA/SiO2 composition, achieving a compressive strength of 7.8 MPa and mimicking trabecular bone properties. The second phase focuses on synthesizing and modifying triphasic ceramic powders, including calcium phosphate (TCP), HA, and calcium phosphate silicate (CPS). Coating the triphasic powder with silicon dioxide (SiO2) using tetraethyl orthosilicate (TEOS) significantly enhanced the mechanical properties, with a 117% increase in compressive strength (up to 9.05 MPa). These modified materials were optimized for Direct Ink Writing (DIW) 3D printing. In the third phase, the fracture behavior of polymer-infiltrated ceramic scaffolds (PICNs) was studied using Voronoi tessellation designs for mixed-mode fracture testing. The DIW-printed scaffolds, infiltrated with chitosan polymer, demonstrated improved toughness. Fracture testing was conducted using Brazilian Disk (BD) and Short Beam Bend (SBB) samples, with the Infiltrated Composite Isomorphism Model (ICIM) and Generalized Maximum Tangential Stress (GMTS) criterion predicting fracture loads. Finite Element Method (FEM) analysis showed reliable fracture behavior predictions, with an average error of 23%. The results show significant improvements in the mechanical performance and fracture resistance of ceramic/polymer scaffolds, paving the way for more effective, load-bearing medical implants. The optimized scaffold designs offer promising solutions for future advancements in bone regeneration, contributing to the development of personalized medical implants for enhanced patient outcomes.
