The Enhancement Of Nano-particles On The Mechanical Properties Of Bone Scaffold

Abstract:Selective laser sinering is regatded to be a kind of promising technology for the fabrication of artificial bone. Biodegradable polymers and bioceramics are considered as promising bone replacement material. While the scaffolds fabricated with these materials are lack of sufficient mechanical properties, which limited their load-bearing application. In this study, polymer scaffolds and ceramic scaffolds were fabricated via selective laser sintering and the properties of the scaffolds were improved by nano-reinforcement phase. It focused on the influencing of the content of nano-reinforcement phase on the mechanical properties of scaffolds. The main research work and innovative results are as follows:1. Structural improvement was proposed based on an independently developed selected laser sintering system. The three dimensional geometric models were built by Solidworks and structural analysis was done via Ansys. The results show that the bending deformation of the machine reduced from0.935mm to0.25mm.2. Polymer scaffolds were fabricated via selective laser sintering with the addition of different content of nano-HAP. It is discovered that with the content of nano-HAP increasing from0wt%to20wt%, the optimum compressive strength and modules of the scaffolds were3.28MPa and32.81MPa, respectively. The results demonstrate that the introduction of nano-reinforcement phase can enhance the mechanical properties of scaffolds.3. Porous ceramic scaffolds enhanced by nano-ZrO2were fabricated via selective laser sintering. The results showed that the phase transformation of monoclinic phase (m-ZrO2) into tetragonal phase (t-ZrO2) occurred after sintering, which is favorable for the reinforcing ability of ZrO2due to the stress-induced phase transformation toughening mechanism. The compressive strength and fracture toughness of the scaffolds increased from17.9MPa to44.1MPa and1.14MPa·m1/2to1.66MPa·m1/2, respectively.4. The mechanical properties of the ceramic scaffolds were further inproved by the addition of nano-SiO2and CNTs. The average grain size of the scaffolds decreased and the mechanical properties of the scaffolds increased when the content of nano-SiO2increased from0to5wt%. The optimum compressive strength and fracture toughness have been improved by about197%and103%as compared with the unmodified scaffolds, which increased by54%and23%than the scaffolds with only5wt%nano-SiO2. The results demonstrated that the addition of two types of nano-reinforcement phase can obtained a better strengthening effect on the mechanical properties of scaffolds.