Controlled mechanical and mass-transport properties of porous scaffolds through hollow strut

The rational design of bone implants is relatively complex because they should meet a unique combination of mechanical, mass-transport, and biological properties for favorable performance. However, in conventional topological structures of scaffolds, some important properties are coupled, which hampers the achievement of optimal performance. For example, it is difficult to enhance the stiffness and mass-transport properties of a scaffold simultaneously. This study aims to obtain controlled mechanical and mass-transport properties of scaffolds through adding an inner pore within the strut. The experimental results suggest that permeability and mechanical property were decoupled to a good extent, e.g., the elastic modulus of the four fabricated samples ranges from 1428.6 MPa to 3924.4 MPa, while the counterpart permeability distribution ranges from 11.08 × 10⁻⁹ m² to 12.35 × 10⁻⁹ m² (only 10% difference). Then, combination of the stiffness and permeability was controlled through porosity and inner pore. The simulated results show that permeability is sensitive to both the added inner pore and porosity while elastic modulus depends largely on the porosity, which provides a robust and straightforward approach to tailor the mechanical and mass-transport properties. The hollow-strut structure allows for greater design freedom in the combination of multi-physical properties, which provides a promising basis to the design of high-performance bone implants.