An interdisciplinary team of Missouri S&T researchers is creating organ tissue samples using bioactive glass, stem cells and a 3-D printer. The project could advance pharmaceutical testing and lead to a better understanding of how diseases affect human cells.
The researchers grow stem cells and add them to hydrogels made of alginate, gelatin or similar substances. Then, in a step unique to Missouri S&T, the researchers add bioactive glass to supply needed calcium ions to the hydrogel/cell mixture and load the mixture as bioink into a 3-D printer. They test the samples after bioprinting to determine the stem cell function, the material’s tensile strength, degradation and the best glass type to add.
“Different cells prefer different gels, so we work to find which gel combination suits our research,” says Dr. Krishna Kolan, a postdoctoral researcher at S&T. “The challenge is that dissolved glass adds calcium, but it changes the pH, and cells need neutral pH to survive. We figured out which glass and how much to add to maintain neutral pH.”
Kolan says researchers are several years away from making a functioning organ, such as a liver or kidney, and the challenge is the vascular system and multiple types of cells in those organs. S&T researchers are working on ways to develop vascular systems within the bioprinted tissue. Kolan says they can imbed a channel into engineered tissue during printing, then line the channel with endothelial cells, which are the primary cells in blood vessels. He is working on the experiments with two undergraduate students: August Bindbeutel (mechanical engineering) and Lesa Steen (materials science and engineering).
“Endothelial cells form networks in environments they like, such as glass-infused hydrogel,” Kolan says. “As the network grows, it vascularizes the tissue.”
As researchers work toward someday repairing or replacing organs with engineered organs, they are creating tissue models that can be used for pharmaceutical testing, Kolan says. Companies can scale down the composition of a drug to be appropriate for a tissue sample, he says. S&T researchers are also currently working on 3D-printed bone models. Biology graduate student Bradley Bromet is comparing diseased cells with healthy stem cells to see in 3D how a disease – diabetes, for instance – affects cells.
Kolan is working on the project with Dr. Ming Leu, the Bailey Professor in S&T’s mechanical and aerospace engineering department; Dr. Richard Brow, interim deputy provost in the materials science and engineering department; Dr. Delbert Day, Curators’ Professor Emeritus of ceramic engineering, and Dr. Julie Semon, assistant professor of biology and director of S&T’s Laboratory of Regenerative Medicine.
The research project showcases the types of research that complement the University of Missouri System’s NextGen Precision Health Initiative. NextGen is expected to accelerate medical breakthroughs and improve lives by harnessing the research being done at the system’s four universities and training a new generation of health scientists and practitioners.
What kinds of stem cells are you using, and are some more promising than others?
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