Scientists have successfully managed to figure out a way of 3D printing artificial versions of the complex vascular networks of the human body that can mimic natural passageways for blood, air, lymph, and other vital fluids. The process used for this task is called SLATE, stereolithography apparatus for tissue engineering.
Jordan Miller, assistant professor of bioengineering at Rice’s Brown School of Engineering and team leader, said, ‘One of the biggest roadblocks to generating functional tissue replacements has been our inability to print the complex vasculature that can supply nutrients to densely populated tissues.’
According to Miller, our organs have their own vascular networks such as the lung’s airways and blood vessels, and blood vessels and bile ducts in the liver. He says, ‘These interpenetrating networks are physically and biochemically entangled, and the architecture itself is intimately related to tissue function.’ However, Miller and his team are the pioneers in developing bioprinting technology that ‘addresses the challenge of multi vascularization in a direct and comprehensive way.’
The task of developing functional tissue replacements is currently a top priority because of its profound impact on organ donations. The organ shortage is best defined as a long-term crisis. About 114,000 people are on waiting lists in the United States only. Furthermore, even after a successful transplant, these patients have to continue to administer immune-suppressing drugs for preventing organ rejection. Bioprinting of organs could put an end to this.
Kelly Stevens of the University of Washington, who led the team of bioengineers with Miller, said, ‘Tissue engineering has struggled with this for a generation. With this work, we can now better ask, ‘If we can print tissues that look and now even breathe more like the healthy tissues in our bodies, will they also then functionally behave more like those tissues?’ This is an important question, because how well a bioprinted tissue functions will affect how successful it will be as a therapy.’
While heart and brain are generally considered to be among the most intricate of organs, other organs are not so simple either. Stevens says, ‘The liver is especially interesting because it performs a mind-boggling 500 functions, likely second only to the brain. The liver’s complexity means there is currently no machine or therapy that can replace all its functions when it fails. Bioprinted human organs might someday supply that therapy.’
The team has come up with a new open-source bioprinting technology that has been termed as ‘stereolithography apparatus for tissue engineering’ or SLATE. During the SLATE procedure, individual layers are printed using a liquid pre-hydrogel solution. Once the solution is exposed to the blue light, it solidifies. Reprinting human organs will also enable scientists to understand how cancer affects the organs.