Horsetail-inspired lattice structures for bone scaffold applications

A well-design bone scaffold is critical for facilitating post in vivo implantation recovery. Key factors, such as elastic moduli matching to alleviate stress shielding, anisotropic characteristics, and sufficient porosity for cell ingrowth, shape the design consideration for bone scaffolds. Herein, we propose a novel body-centered cubic (BCC) lattice with modified horsetail inspired cross-section strut members as the building block for synthetic bone scaffold application. We demonstrated that geometrical parameters can be varied to attain expected desirable mechanical properties. We also successfully matched the performance of the physical compression tests of Ti-6Al-4V-based samples manufactured using selective laser melting to that of the simulation environment to facilitate design. Through our work, we created Ti-6Al-4V-based lattices, which match the mechanical performance of native bone in terms of elastic moduli and yield strength. Biologically, the lattices provide in-strut pore dimensions that facilitate bone cell ingrowth as well as yield point that is beyond the strain required to promote secondary healing. The good energy absorption capability of our lattices also adds resilience to accidental damage when applied for use in bone scaffold design. We also discovered that the isotropy characteristic is decoupled from the outer radius of the designed lattice; this avoids convolution that would otherwise increase design difficulties. Through this novel design, the tuning of the mechanical properties to attain the key considerations with geometrical variations is made possible.