Mechanical and microstructural properties of polycaprolactone scaffolds with one-dimensional, two-dimensional, and three-dimensional orthogonally oriented porous architectures produced by selective laser sintering.

This article reports on the experimental determination and finite element modeling of tensile and compressive mechanical properties of solid polycaprolactone (PCL) and of porous PCL scaffolds with one-dimensional, two-dimensional and three-dimensional orthogonal, periodic porous architectures produced by selective laser sintering (SLS). PCL scaffolds were built using optimum processing parameters, ensuring scaffolds with nearly full density (>95%) in the designed solid regions and with excellent geometric and dimensional control (within 3-8% of design). The tensile strength of bulk PCL ranged from 10.5 to 16.1 MPa, its modulus ranged from 343.9 to 364.3 MPa, and the tensile yield strength ranged from 8.2 to 10.1 MPa. These values are consistent with reported literature values for PCL processed through various manufacturing methods. Across porosity ranged from 56.87% to 83.3%, the tensile strength ranged from 4.5 to 1.1 MPa, the tensile modulus ranged from 140.5 to 35.5 MPa, and the yield strength ranged from 3.2 to 0.76 MPa. The compressive strength of bulk PCL was 38.7 MPa, the compressive modulus ranged from 297.8 to 317.1 MPa, and the compressive yield strength ranged from 10.3 to 12.5 MPa. Across porosity ranged from 51.1% to 80.9%, the compressive strength ranged from 10.0 to 0.6 MPa, the compressive modulus ranged from 14.9 to 12.1 MPa, and the compressive yield strength ranged from 4.25 to 0.42 MPa. These values, while being in the lower range of reported values for trabecular bone, are the highest reported for PCL scaffolds produced by SLS and are among the highest reported for similar PCL scaffolds produced through other layered manufacturing techniques. Finite element analysis showed good agreement between experimental and computed effective tensile and compressive moduli. Thus, the construction of bone tissue engineering scaffolds endowed with oriented porous architectures and with predictable mechanical properties through SLS is demonstrated.