Three-Dimensional Printed Biomimetic Elastomeric Scaffolds: Experimental Study of Surface Roughness and Pore Generation

Abstract

Tissue engineering is an emerging field within biomedicine, related to developing functional substitutes for damaged tissues or organs. Despite significant advancements, the development of effective engineering tissue constructs remains challenging, particularly when replicating elastic stretchability, which plays a critical role in many tissues. Therefore, the development of tough, elastomeric scaffolds that mimic the complex elasticity of native tissues, such as the myocardium, heart valves, and blood vessels, is of particular interest. This study aims to evaluate a flexible printable material (Formlabs' Elastic 50A Resin V2) to develop porous 3D scaffolds using additive manufacturing stereolithography (SLA). The elastomeric samples were tested in relation to their swelling behaviour, mechanical properties, and exposure to low temperatures. Additionally, the effects of print orientation, water immersion, and exposure to low temperatures on surface roughness and porosity were investigated to determine the best conditions to enhance scaffold performance in biomedical applications. The results demonstrated that samples printed at 0°, immersed in water, and exposed to low temperature (-80 °C) showed a more uniform microporosity, which could improve the adhesion and growth of cells on the scaffold. This research highlights a practical and economical approach to enhancing elastomeric scaffolds, paving the way for improved outcomes in tissue engineering applications.

Keywords: additive manufacturing; biomimetic scaffold; elastomeric resin; printing orientation; roughness; stereolithography; surface porosity.

Figure 1

Main steps to produce the specimens: (A) slicing phase; (B) final stage of production; (C) post-processing; (D) specimen placed in Petri dish for the immersion phase.

Figure 2

Trends in the stress–strain curves as a function of the dive time.

Figure 3

Two-dimensional surface analysis of printed samples before immersion: representative images of roughness profiles (Ra, µm), taken by a Mitaka noncontact surface profiler, for samples printed at three different orientations (0°, 45°, and 90° with respect to the printing plane).

Figure 4

Three-dimensional surface analysis of printed samples before immersion (reference values). The analyses carried out show that the surfaces, before immersion and treatment at low temperatures, are free of defects, except for those derived from the printing process.

Figure 5

Two-dimensional surface analysis of samples after thermal exposure at −20 °C. Representative images of roughness profiles (Ra, µm), taken by a Mitaka noncontact surface profiler, for samples printed at three different orientations (0°, 45° and 90°, with respect to the printing plane).

Figure 6

Three-dimensional surface analysis of samples after thermal exposure at −20 °C. The acquisition shows that, after the first treatment at low temperatures (−20 °C), pore formation occurs on the surface, caused by the expansion of water during the transition to a solid state.

Figure 7

Two-dimensional surface analysis of samples after thermal exposure at −80 °C: typical roughness profiles (Ra, µm). Representative images of roughness profiles (Ra, µm), taken by a Mitaka noncontact surface profiler, for samples printed at three different orientations (0°, 45°, and 90° with respect to the printing plane).

Figure 8

Three-dimensional surface analysis of samples after thermal exposure at −80 °C. The acquisition shows that, after the second treatment at low temperatures (−80 °C), pore formation occurs on the surface, caused by the expansion of water during the transition to the solid state.

Figure 9

Surface analysis: (A) surface roughness (Sa%); (B) Ra% along X-axis; (C) Ra% along Y-axis.

Figure 10

Representative images of samples before and after treatment at low temperatures@ magnification of 160×. Data in the red areas were acquired by 3D scans.