The team of Jordan Miller, assistant professor at the Brown School of Engineering (USA), has developed a 3D bioprinting technology that solves the problem of multivascularization. Simply put, they learned how to create a complex, intricate structure of the smallest vessels of arbitrary purpose on a 3D printer. This opens the way for printing analogs of the most complex and important organs in the human body.
The problem of multivascularization is that it is not enough to create large vessels and arteries - in addition to them, each organ contains tens and hundreds of its own channels for pumping blood, lymph and air. All of them are grouped in a small volume, often intertwined with each other, and in some places they intersect. This is a real labyrinth, which until recently was considered almost impossible to recreate.
Miller and his team created the "tissue engineering stereolithography apparatus" or SLATE, leaving the source code of the technology open. This is a type of 3D printer that works with a hydrogel that can harden when exposed to ultraviolet light. The printer creates an object in very high resolution, about 10-50 microns, layer by layer forming a network of capillaries. As a test, an analogue of artificial lungs was printed, which proved to be strong enough to withstand expansion-contraction when air was pumped through it.
In the printed structure, the vessel walls are flexible enough, but always retain their shape so that large red blood cells can pass through them without creating plugs. Scientists can vary many parameters of such organs - for example, so that the printed implant compensates for the birth defects of the native organ and improves its performance. And in the future, Miller's colleagues hope that they will be able to print the entire working organ, not only for transplants, but also as a model for studying cancer, in order to better understand how it captures various parts of the body.