4D PRINTING OF SELF-FITTING SCAFFOLDS WITH NATURE INSPIRED ARCHITECTURE

Abstract

The implantation of bio-degradable scaffolds is considered as a promising approach to address the repair of bone defects. This thesis report aims to develop a computational approach to study the mechanical behaviour, fluid dynamic, and degradation impact on Polylactic Acid scaffolds with different nature-inspired design structures. Scaffold design is considered to be one of the main factors for the regulation of mechanical characteristics and fluid flow dynamics. In this thesis report, five scaffolds with different nature-inspired architectures have been designed. Based on finite element analysis, their mechanical behaviour in terms of total deformation, equivalent stress, and strain have been predicted. The computational fluid dynamic study is carried out to observe the fluid velocity profile, pressure distribution, and those parameters are used to evaluate fluid perfusion within the scaffold by determining the permeability using Darcy’s law. In addition, diffusion governed degradation analysis of the scaffolds has been performed to compute the total time required for the scaffold to degrade within a given environment. Based on the results of deformation, permeability, and degradation analysis, suitable scaffolds that mimic the properties of cancellous bone have been identified. 4D printing can fabricate dynamic structures with adjustable shapes, properties, or functionality. 3D printing of designed scaffolds is performed using a smart material (Polylactic Acid). Preliminary experiments of 4D printing are performed using the same smart material by observing the shape-memory transformation of 3D printed strips. The 3D printed strips are then transformed to a metastable state by folding it to a specific angle. The shape-memory effect is activated when the strip is externally heated at a temperature above the glass transition temperature, after which it transformed into its permanent shape.