Making a permanent, natural-looking skin replacement to cover burn wounds or other injuries has been an uphill task. This has been so especially for bioengineers for decades. But we are getting closer to this soon. Thanks to the new method for 3D printing skin full functioning blood vessels.
A research conducted by Yale University and RPI (Rensselaer Polytechnic Institute) utilizes human skin cells converted into a liquid (bio ink). Basically, the bio ink is utilized to print artificial skin that then develops its individual blood vessel mechanism.
“The vasculature is very important because that’s how the host and the graft talk to each other,” says the professor of chemical and biological engineering at RPI, Pankaj Karande. Karande led this research. “Communication between host and graft is critical if the skin substitute is not to be rejected by the body.” He adds.
Presently, patients that need skin grafts have two alternatives. One of them is autologous grafts. This is where the doctors cut a section of fresh skin. They use it to cover a wounded area. Another one is using artificial products. The products are majorly made from materials that vary from polymer foam to bovine collagen. The two options have their disadvantages.
The autologous skin graftings are uncomfortable and they generate a new wound. The artificial skin stuff have a variety of limitations. These products are usually temporary, they do cover deep wounds. Also, they do not match human skin. According to Karande, they are only Band-Aids or dressings.
The Yale team and RPI are created using bio ink that contains cells from a newborn foreskin and human endothelial colony-forming cells. They are also created using bio ink that contains cells from the placenta tissue’s human placental pericytes. All dissolved in a rat tails’ collagen.
This creates the internal skin layer, the dermis. The second bio ink, created from a different kind of human foreskin cells and keratinocytes. It’s printed on the top to create the external coating of the skin called the epidermis.
While in a petri dish, the placental pericytes and the endothelial cells start to gather themselves into minute vascular networks.
This team of researchers implanted the graftings in mice. The discovered that the blood vessels joined with the mice’s own vascular networks in four weeks. Therefore, this implied that blood was moving between the skin graft the mouse.
“We see that the graft stays there longer, and that the skin matures and becomes closer to what we would see in native human tissue,” says Karande. Karande continued to say that these are vital for aesthetics and function. “You want the skin at the graft site to look as much like the surrounding skin.” Said Karande.
The aesthetic question of color is one issue the researchers are facing. A graft for an individual of Indian roots needs to be darker as compared for a light Nothern European. The color of skin is determined by the cells concentration known as melanocytes. These can be included in the bio ink in lesser or greater amounts based on the desired color.
“We’re still at the basic research stage. We’re still figuring out the basic problems and what the right answers might be.” Says Karande.