Here’s a new recipe for creating living tissue: Impale tiny clumps of cells onto needles, much like miniature shish kebab skewers. Instead of heading to a tiny BBQ grill, you wait while the cells grow together to form the tissue you want — perhaps skin, or a section of blood vessel.
Researchers at Indiana University are among the first in the United States to have direct access to a 3D bioprinter using that innovative technology to create living tissue, now for use in research laboratories, and potentially for use in humans.
Traditional 3D printers create objects in layers by applying a fluid cell-embedding substance (“bio-ink”) through a nozzle. The new machine uses a robot to place the tiny spheres of cells on the needles, carefully arranging them by cell type and location. The spheroids are assembled snugly against each other, enabling them to fuse together into the desired form of tissue.
Scientists will be using the instrument, distributed by the Japanese firm Cyfuse, to conduct research in tissue engineering and regenerative medicine projects in fields ranging from vascular and musculoskeletal biology to dermatology, ophthalmology and cancer, said David B. Burr, Ph.D., associate vice chancellor for research at Indiana University-Purdue University Indianapolis, professor of anatomy and cell biology at the IU School of Medicine and of biomedical engineering at IUPUI.
“We have a large and robust group of investigators in these fields who are interested in 3D bioprinting for aspects of their work,” Dr. Burr said. “Having this device positions us, and these investigators, to conduct research and obtain grant funding in new areas that many universities are simply not able to compete for yet.”
The Cyfuse printer, named Regenova, uses a small robot to place the tiny spheroids — each containing about 20,000 cells — onto the needle array. The types of cells, and their arrangements, vary depending on the tissue needed. Once assembled, the cells “know” how to do the rest, organizing themselves into the tissue needed. When ready, the tissue is removed from the spines.
Cyfuse calls its methodology “kenzan,” a reference to the plate with needles — also called the spiky frog — used to affix plants in ikebana, the Japanese art of flower arrangement.
“Putting the printer in our hands immensely empowers us to do constructs no one has done before,” said Nicanor Moldovan, Ph.D., an adjunct associate professor of biomedical engineering and of ophthalmology and a member of the Biocomplexity Institute at IU Bloomington.
Dr. Moldovan, whose interest is in tissue engineering, argues that by enabling the cells to create their own external structure — extracellular matrix – rather than adding it as “bio-ink,” the resulting tissues are much more likely to gain approval from the Food and Drug Administration for human use in the future.
Bioprinting from traditional 3D printers creates some issues. It requires the use of gels to carry cells through the printer nozzle that are compatible with the cells and the tissue being created. Fragments of the biogel remain, which would be seen as foreign, if not toxic, agents. Moreover, Dr. Moldovan said, forcing the gel mixture through the printing tip creates shear forces that can damage the cells.
Other IU researchers with plans for the device include:
- Karl Koehler, Ph.D., assistant professor of otolaryngology-head & neck surgery, who has been working on techniques to create inner ear tissues in a collaboration with Eri Hashino, Ph.D., Ruth C. Holton Professor of Otology. “With our model, we hope to create cranial tissues, such as inner ear and skin,” Dr. Koehler said.
- John Foley, Ph.D., associate professor of anatomy and cell biology in Bloomington, plans to use the printer to help with his lab’s research into the cellular signaling that produces and maintains the specialized skin of the nipple areola and eventually to regenerate the tissue for use in breast reconstruction following mastectomy.
- Nutan Prasain, Ph.D., assistant research professor in the Wells Center for Pediatric Research, and his team have been using the machine to make blood vessels from umbilical cord blood and induced pluripotent stem cell-derived endothelial colony forming cells in collaboration with Mervin C. Yoder, M.D., Richard and Pauline Klingler Professor of Pediatrics. “We believe these printed vessels could be used as implantable vessels for vascular repair,” Dr. Yoder said.
- Melissa Kacena, Ph.D., associate professor of orthopaedic surgery, said that in collaboration with Tien-Min Gabriel Chu, D.D.S., Ph.D., associate dean for research, IU School of Dentistry, and Diane Wagner, Ph.D., associate professor of mechanical engineering at IUPUI, she hopes to use the printer to construct segments of bone for laboratory testing. “Should this approach be successful, in the future we envision using the patients’ own cells to create a patient-specific, anatomically shaped bone segment to replace one that is missing due to injury or disease,” Dr. Kacena said.
- Hiroki Yokota, Ph.D., professor of biomedical and mechanical engineering, and of anatomy and cell biology, plans to use the instrument to study the bone metastasis of cancer cells, as well as some musculoskeletal applications.
Dr. Burr predicted that the use of bioprinted tissue as replacement tissue following traumatic injury is no more than a decade away. Having such a machine on campus enables researchers to to do the necessary hands-on work to create the initial cell constructs and engineer the proper geometries and configurations, he said.
The interest shown by Dr. Moldovan and others in Indianapolis, including Keith March, M.D., director of the Indiana Center for Vascular Biology and Medicine, was instrumental in the agreement reached by Cyfuse and IU, said Cyfuse representative Steven Boikess.
“There is a lot to be learned and gained on both sides from this relationship. I think it’s very clear that Cyfuse is passionate about helping the researchers at IUPUI generate the best constructs possible to give the best chance of success,” Boikess said.
Under the agreement, IU is leasing the $450,000 instrument while preparing a National Institutes of Health instrument grant proposal that would enable outright purchase of the machine.