A recent development achieved by American researchers, better mimicking of native vessels and ducts in human body can be made by a special way of “printing” them in tubular structures.
The researchers have developed a 3-D bio-printing technique that allows them to accurately fine-tune the properties of the printed tissues such as the number of layers to be printed and the ability to transport nutrients through them. This was revealed in the research which was recently published in the scientific journal Advanced Materials.
The study claimed that the more complex and advanced tissues that are thus produced have the potential to act as replacements for tissues that are already damaged.
“The vessels in the body are not uniform,” said Zhang Yu, senior author on the study and a researcher in Brigham and Women’s Hospital’s Department of Medicine. “This bio-printing method generates complex tubular structures that mimic those in the human system with higher fidelity than previous techniques.”
Human cells were mixed with a hydrogel by the researchers. A hydrogel is a flexible structure that is made up of hydrophilic polymers. The researchers then optimized the chemistry of the hydrogel so that it would be possible to allow the human cells to proliferate, or “seed,” throughout the mixture.
In the next step, the scientists filled up a 3D bio-printer cartridge with the bio-ink. A customized nozzle was fitted to the bio-printer which allowed the researchers to print tubular structures in a continuous manner where the structures contained up to three layers.
The new discovery can have a number of practical medical applications. For example, blood vessels are damaged because of diseases such as arteritis, atherosclerosis and thrombosis. Further, according to the study, there can be inflammatory lesions and deleterious congenital anomalies in the urothelial tissue.
Tissues that very accurately mimic both vascular tissue and urothelial tissue were able to be printed efficiently by the researchers.
The researchers combined together human urothelial, bladder smooth muscle cells and the hydrogel to create the urothelial tissue. A combination of human endothelial cells, smooth muscle cells and the hydrogel were put to use by the researchers to print the vascular tissue.
The printed tubes were of varying sizes, thicknesses and properties.
Because of the complex nature of natural tissues, one of the critical aspect to make the printed tissues viable as a replacement for native tissues was the structural complexity of the bio-printed tissue, according to Zhang.
For example, a number of layers make up blood vessels where each of the layers are made up of multiple types of cells.
“Our goal is to create tubular structures with enough mechanical stability to sustain themselves in the body,” said Zhang.
(Adapted from Xinhuanet.com)