Spatially varying porosity with continuous path plan for hollowed tissue scaffolds

In this paper, a bio-inspired scaffold design has been proposed by incorporating its functional (biological requirement) and fabrication constraint into the design processes. The proposed new methodology generates functionally gradient porosity along the hollowed scaffold architecture with desired level of control by combining two geometrically oriented consecutive layers. The resulting set of layers address the repeatable, interconnected and controllable pores. Modeling of the first layer starts with discretizing internal region by connecting ruling lines between internal and external features using a dynamic programming algorithm. These feature connecting ruling lines act as resolution for the proposed method. Then by accumulating those ruling lines, the region has been divided into equal area sub-regions. In the second layer, the desired pore size and hence the porosity has been achieved by geometrically partitioning those sub-regions. And thus the combined set of layers achieves the desired controlled variational porosity along the scaffold architecture.To ensure a continuous and interconnected tool path, optimized zigzag pattern followed by a concentric spiral like optimal layers are generated based on the required biological and mechanical properties. Several examples will be presented to demonstrate the proposed methodology. The designed examples will also be fabricated layer-by-layer using a micro-nozzle biomaterial deposition system.