Artificial blood vessels.
3D bioprinting has made new headway recently in fabricating blood vessels. Researchers at Brigham and Women’s Hospital have developed a method for 3D printing biological material using magnetically controlled robots.
They have a unique strategy for vascularization of hydrogel constructs that combine advances in 3D bioprinting technology and biomaterials.
The researchers first used a 3D bioprinter to make an agarose (naturally derived sugar-based molecule) fiber template to serve as the mold for the blood vessels. They then covered the mold with a gelatin-like substance called hydrogel, forming a cast over the mold which was then reinforced via photocrosslinks.
Our approach involves the printing of agarose fibers that become the blood vessel channels. But what is unique about our approach is that the fiber templates we printed are strong enough that we can physically remove them to make the channels,” said Khademhosseini. “This prevents having to dissolve these template layers, which may not be so good for the cells that are entrapped in the surrounding gel.”
Khademhosseini and his team were able to construct microchannel networks exhibiting various architectural features. They were also able to successfully embed these functional and perfusable microchannels inside a wide range of commonly used hydrogels, such as methacrylated gelatin or poly(ethylene glycol)-based hydrogels at different concentrations.
A previous approach with untethered magnetic microrobots
Previously in February, 2014 : Researchers at Brigham and Women’s Hospital (BWH) and Carnegie Mellon University have introduced a unique micro-robotic technique to assemble the components of complex materials, the foundation of tissue engineering and 3D printing.
The presented approach uses untethered magnetic micro-robotic coding for precise construction of individual cell-encapsulating hydrogels (such as cell blocks). The micro-robot, which is remotely controlled by magnetic fields, can move one hydrogel at a time to build structures. This is critical in tissue engineering, as human tissue architecture is complex, with different types of cells at various levels and locations. When building these structures, the location of the cells is significant in that it will impact how the structure will ultimately function. “Compared with earlier techniques, this technology enables true control over bottom-up tissue engineering,” explains Tasoglu.
Tasoglu and Demirci also demonstrated that micro-robotic construction of cell-encapsulating hydrogels can be performed without affecting cell vitality and proliferation. Further benefits may be realized by using numerous micro-robots together in bioprinting, the creation of a design that can be utilized by a bioprinter to generate tissue and other complex materials in the laboratory environment.