Soft-Tissue-Mimicking Using Hydrogels for the Development of Phantoms

TLDR

Mimicking the mechanical properties of soft living tissues is challenging due to limited materials, technologies, and data, making tissue phantoms a promising solution. The study aimed to identify suitable hydrogels for soft‑tissue phantoms by testing organs such as liver, heart, kidney, and brain against materials like agarose, PVA, PHY, and GelMA. Mechanical testing measured viscoelasticity, hardness, and non‑linear elastic response of the organ–hydrogel pairs, followed by correlation analysis to link tissue properties with material performance. Results showed significant variability among tissues; 1 % wt agarose best mimics liver, 2 % wt agarose heart, 4 % wt GelMA kidney, and 4 % wt GelMA plus 1 % wt agarose brain, while PVA and PHY were unsuitable.

Abstract

With the currently available materials and technologies it is difficult to mimic the mechanical properties of soft living tissues. Additionally, another significant problem is the lack of information about the mechanical properties of these tissues. Alternatively, the use of phantoms offers a promising solution to simulate biological bodies. For this reason, to advance in the state-of-the-art a wide range of organs (e.g., liver, heart, kidney as well as brain) and hydrogels (e.g., agarose, polyvinyl alcohol -PVA-, Phytagel -PHY- and methacrylate gelatine -GelMA-) were tested regarding their mechanical properties. For that, viscoelastic behavior, hardness, as well as a non-linear elastic mechanical response were measured. It was seen that there was a significant difference among the results for the different mentioned soft tissues. Some of them appear to be more elastic than viscous as well as being softer or harder. With all this information in mind, a correlation between the mechanical properties of the organs and the different materials was performed. The next conclusions were drawn: (1) to mimic the liver, the best material is 1% wt agarose; (2) to mimic the heart, the best material is 2% wt agarose; (3) to mimic the kidney, the best material is 4% wt GelMA; and (4) to mimic the brain, the best materials are 4% wt GelMA and 1% wt agarose. Neither PVA nor PHY was selected to mimic any of the studied tissues.