Bioink is safe for artificial organ printing
(Nanowerk News) The development of biomaterials for artificial organs and tissues is active due to the increase in accidental injuries and chronic diseases, along with the influx of very old people. 3D bioprinting technology, which uses cells and biomaterials to create three-dimensional artificial tissue structures, has recently gained popularity. However, commonly used hydrogel-based bioinks can cause cytotoxicity due to chemical crosslinking agents and ultraviolet light linking the molecular structures of 3D printed bioinks that are being photographed.
Research team Dr. Song Soo-chang at the Center for Biomaterials, Korea Institute of Science and Technology (KIST), disclosed the first development of a poly(organophosphazene) hydrogel-based temperature sensitive bioink which stably maintains its physical structure only by temperature control without photocuring, induces tissue regeneration, and then decomposes in the body after a certain period of time (Small, “Thermo-Responsive Nanocomposite Bioink with Growth Factor Retainer and Its Application to Bone Regeneration”).
Current hydrogel-based bioinks must undergo a photocuring process to improve the mechanical properties of 3D scaffolds after printing, with a high risk of side effects on the human body. In addition, there are possible side effects by transplanting externally cultured cells into the bioink to enhance the tissue regeneration effect.
Therefore, the research team developed a new bioink material using a temperature-sensitive poly(organophosphazene) hydrogel, which exists in liquid form at low temperatures and turns into a hard gel at body temperature. This allows tissue regeneration only by temperature control without chemical crosslinking agents or UV irradiation and fabrication of a three-dimensional scaffold with a physically stable structure, minimizing possible immune side effects in the human body.
The developed bioink also has a molecular structure that can interact with growth factors, namely proteins that help tissue regeneration to maintain growth factors that regulate cell growth, differentiation, and immune response in the long term. The research team was able to maximize the effect of tissue regeneration by creating an environment in which cell differentiation could be self-regulated in a bioink-printed 3D scaffold.
The research team fabricated a 3D scaffold by printing it with a 3D bioprinter using bioink containing transforming growth factor beta 1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2), which are required for cell infiltration and bone regeneration, and conducted experiments by implanting them to broken bone in mice. As a result, cells from the surrounding tissue migrated to the scaffold, and the damaged bone was regenerated to a normal tissue level, and the implanted 3D scaffold slowly decomposed in the body for 42 days.
Song Soo-Chang of KIST said, “The research team has transferred the technology for thermosensitive polyphosphazene hydrogel to NexGel Biotech Co., Ltd. in June 2022, and the development of products such as bone graft materials and cosmetic fillers is underway.” “Because the bioinks developed this time have different physical properties, further research to apply them to tissue regeneration other than bone tissue is underway, and we hope to eventually commercialize bioinks tailored to each tissue and organ,” he said.