Review of additive manufactured tissue engineering scaffolds: relationship between geometry and performance

Abstract

Material extrusion additive manufacturing has rapidly grown in use for tissue engineering research since its adoption in the year 2000. It has enabled researchers to produce scaffolds with intricate porous geometries that were not feasible with traditional manufacturing processes. Researchers can control the structural geometry through a wide range of customisable printing parameters and design choices including material, print path, temperature, and many other process parameters. Currently, the impact of these choices is not fully understood. This review focuses on how the position and orientation of extruded filaments, which sometimes referred to as the print path, lay-down pattern, or simply “scaffold design”, affect scaffold properties and biological performance. By analysing trends across multiple studies, new understanding was developed on how filament position affects mechanical properties. Biological performance was also found to be affected by filament position, but a lack of consensus between studies indicates a need for further research and understanding. In most research studies, scaffold design was dictated by capabilities of additive manufacturing software rather than free-form design of structural geometry optimised for biological requirements. There is scope for much greater application of engineering innovation to additive manufacture novel geometries. To achieve this, better understanding of biological requirements is needed to enable the effective specification of ideal scaffold geometries.

Porous Calcium Phosphate Ceramic Scaffolds with Tailored Pore Orientations and Mechanical Properties Using Lithography-Based Ceramic 3D Printing Technique

“…Regardless of the pore orientations, all three porous CaP scaffolds exhibited similar fracture behaviors with the compressive stress increasing linearly and then dropping very rapidly. This mechanical response can be attributed to the brittle nature of the CaP frameworks, which is often the case with porous ceramics [ 44 ]. However, it should be noted that the compressive stress and strain at the fracture, which are marked by the arrows, were strongly affected by the pore orientation.…”

Investigating Commercial Filaments for 3D Printing of Stiff and Elastic Constructs with Ligament-Like Mechanics

“…3D printing of polymeric scaffolds can generate mechanically competent structures that can act as templates for tissue formation and regeneration [ 25 , 26 ]. 3D printing can also create sophisticated, porous scaffolds with complex geometry not possible with traditional manufacturing processes [ 27 , 28 ]. Using fused deposition modelling (FDM), many 3D printing parameters can be controlled.…”

Screening of Additive Manufactured Scaffolds Designs for Triple Negative Breast Cancer 3D Cell Culture and Stem-Like Expansion

“…These results represented that proliferation was greater when cells had more available material and corners to attach to and grow on. It was described that scaffold geometry affects cell seeding and proliferation and must be optimized for each cell type [ 39 ]. Sobrat et al demonstrated that orientation and layout of filament are significantly important for biological experiments.…”