Bakken, C. | Search bioRxiv

bioRxiv2020

PolyJet 3D Printing of Tissue Mimicking Materials: An Investigation of Characteristic Properties of 3D Printed Synthetic Tissue

Current anatomical 3D printing has been primarily used for education, training, and surgical planning purposes. This is largely due to the models being printed in materials which excel at replicating macro-level organic geometries; however, these materials have the drawback of unrealistic mechanical behavior and system properties compared to biological tissue. The new Digital Anatomy (DA) family of materials from Stratasys utilizes composite printed materials to more closely mimic mechanical behavior of biological tissue, potentially allowing more realistic models for design evaluation. Various experimental DA Solid Organ (SO) configurations were quantitatively evaluated under axial loading for comparison with porcine liver in terms of stiffness. Additionally, Structural Heart - Myocardium (Myo) configurations were quantitatively evaluated under different lubricant conditions for comparison with porcine epicardium and aorta in terms of lubricity. Finally, experimental DA Subcutaneous Tissue configurations were qualitatively evaluated by experts with significant pre-clinical implant experience for cutting, tunneling, and puncture procedures. In general, the experimental SO configurations showed promising compliance results when compared to porcine liver. The stiffness of DA configurations was either within the same range or on the lower bound of porcine tissue stiffness values. The lubricity of DA configurations with surface treatments was comparable with porcine epicardium and aorta. In terms of qualitative cutting, DA did not perform well for any of the configurations; however, tunneling and puncture were rated favorably for some of the experimental configurations. Despite some limitations, DA feels closer to real tissue than other commercially available 3D printed materials. Furthermore, the lower sample-to-sample variability of DA allows for repeatability not provided by biological tissue. The promising results and repeatability indicate that DA materials can be used to configure structures with similar characteristic mechanical properties to porcine liver, epicardium, and subcutaneous tissue, adding new value as not only an educational, training, and surgical tool, but also as a research tool.

bioengineering↗

bioRxiv2019

Polyjet 3D printing of tissue-mimicking materials: how well can 3D printed synthetic myocardium replicate mechanical properties of organic myocardium?

Anatomical 3-D printing has potential for many uses in education, research and development, implant training, and procedure planning. Conventionally, the material properties of 3D printed anatomical models have often been similar only in form and not in mechanical response compared to biological tissue. The new Digital Anatomy material from Stratasys utilizes composite printed materials to more closely mimic the mechanical properties of tissue. Work was done to evaluate Digital Anatomy myocardium under axial loading for comparison with porcine myocardium regarding puncture, compliance, suturing, and cutting performance.\n\nIn general, the Digital Anatomy myocardium showed promising comparisons to porcine myocardium. For compliance testing, the Digital Anatomy was either within the same range as the porcine myocardium or stiffer. Specifically, for use conditions involving higher stress concentrations or smaller displacements, Digital Anatomy was stiffer. Digital Anatomy did not perform as strongly as porcine myocardium when evaluating suture and cutting properties. The suture tore through the printed material more easily and had higher friction forces both during needle insertion and cutting. Despite these differences, the new Digital Anatomy myocardium material was much closer to the compliance of real tissue than other 3D printed materials. Furthermore, unlike biological tissue, Digital Anatomy provided repeatability of results. For tests such as cyclic compression, the material showed less than two percent variation in results between trials and between parts, resulting in lower variability than tissue. Despite some limitations, the myocardium Digital Anatomy material can be used to configure structures with similar mechanical properties to porcine myocardium in a repeatable manner, making this a valuable research tool.

bioengineering↗