Compressive strength of β-TCP scaffolds fabricated via lithography-based manufacturing for bone tissue engineering

Abstract

Bone is a vital organ that is responsible for the support and movement of body as well as the storage and transportation of cells and nutrients. Disease, along with traumatic events, can leave regions of bone with large voids and/or defects. Related surgical procedures, such as allografts, autografts, and arthroplasty, are reported to amount to roughly €9.6bn annually, emphasising the need for bone repair/replacement globally. Tricalcium phosphate (TCP) is a bioactive ceramic that has been identified as a suitable material for bone tissue engineering applications due to its excellent bioresorbability and overall biocompatibility. Through lithography-based ceramic manufacturing (LCM), β -TCP scaffolds were fabricated across nine different designs in this work. Pore size, unit cell size, and unit cell geometry were altered to vary the porosity of these scaffolds. Following fabrication, the material composition, topography, macrostructure, and microstructure of the β-TCP scaffolds were characterised. The effects of porosity and unit cell geometry on the compressive strengths of β -TCP scaffolds were analysed in detail. Compressive strengths of the scaffolds were measured between 1.4 ± 0.5 MPa and 67.6 ± 13.3 MPa across a porosity range of 5.58 ± 0.09% to 59.36 ± 0.18%. The strength of these scaffolds was considerably lower than that of the compressive strength of cortical bone (100–200 MPa), but mimic the compressive strength of cancellous bone well (0.1–16 MPa). While scaffolds of β-TCP alone may not be suitable for load-bearing applications, they demonstrate enough mechanical stability for bone regeneration/tissue engineering applications. They hold more potential in the regeneration of small bone defects/voids or in composite materials.