Bioink is an innovation that makes it possible to print (parts of) organs and blood vessels used to help tissues heal better or replace them. Researchers at the University of Twente have made significant advances in bioink technology. According to their research this discovery could change the way vascularized tissues can be created.
The innovation that the University of Twente researchers describe in Advanced Healthcare Materials makes it possible to precisely control the growth and organization of small blood vessels in 3D printed tissues. These are blood vessels that mimic the complex networks in the human body.
3D printed blood vessels
The potential of 3D printed organs for medicine is substantial. They can provide solutions to organ failure, tissue damage and even contribute to the development of new therapies. Important for the functioning and survival of 3D printed organs is that these tissues receive sufficient nutrients and oxygen. These are delivered through blood vessels. The ability to print these blood vessels, which the University of Twente researchers have now developed an innovative bioink for, is a major step forward.
The existing technology did allow tissue engineers to position blood vessels during the printing process. However, because these blood vessels experienced unpredictable changes during the culture process in a laboratory or when placed in a body, the functionality of the tissues created was reduced. With the now-developed programmable bioink, this can be solved. Indeed, the technology allows the growth and restructuring of blood vessels to be dynamically controlled. This opens new possibilities for creating tissues with long-term functionality and adaptability.
Innovative bioink with pieces of DNA
The bioink incorporates so-called aptamers, pieces of DNA. These aptamers can be programmed to bind and release biochemical signals as needed. This process mimics the natural mechanism the human body. In it, the microenvironment of tissues acts as a reservoir for growth signals, which are released only when needed. This allows the bioink to direct blood vessel formation and adapt to the needs of the tissue.
“Our lab has previously developed aptamer technology to release proteins that stimulate the growth of new blood vessels. What makes this technology unique is that it works not only in three dimensions, but also over time. We call this 4D control,” say researchers Jeroen Rouwkema and Deepti Rana of the Vascularization Lab at the University of Twente.
By combining this technology with extrusion-based 3D bioprinting, a programmable bioink has been developed that mimics the body's natural way of delivering biochemical signals. “This allows us to control the growth of blood vessels in a controlled laboratory environment. This brings us closer to creating tissues that function like real organs,” said Rouwkema and Rana.
3D printed muscles
Last year, researchers at the Terasaki Institute in Los Angeles also took a big step in the field of bioink. They succeeded then in developing a method to create 3D-printed muscle structures with better alignment and maturation of muscle cells. To do this, microparticles were made that are loaded with insulin-like growth factor (IGF) using a microfluidic platform.
Another bioprinting study was also conducted in the Netherlands last year. Researchers at UMC Utrecht worked there on a technology combining volumetric printing, fast but not “solid,” with “melt electrowriting” (MEW printing). This is a very precise form of 3D printing that works by targeting a narrow filament of molten (biodegradable) plastic. This allows complex structures to be printed that are mechanically strong and can withstand considerable forces.
