Researchers from Rensselaer Polytechnic Institute have developed a new method to 3D print living skin with built-in blood vessels. This living skin construct is cultured in vitro and develops into an interconnected microvascular network underneath a layered barrier of skin cells. in tests on mice, the grafts connect with the animals’ vascular network and become perfused within four weeks after transplantation. This exciting development may one day provide new, more functional skin grafts for patients.
Current artificial skin grafts can fall off due to their lack of integration with the host cells. One of the major challenges for this lack of integration has been absence of a functional vascular system to sustain the transplanted tissue.
The new skin graft is made by 3D printing using a bioink containing fibroblasts, endothelilal cells, and pericytes, collagen and other necessary components was used to pattern the vascularized dermis layer of the skin. Then, keratinocytes, the cells that form the impermeable epidermis of our skin, are printed in a collagen bioink on top of the dermis. After culturing in vitro for tissue maturation, the skin grafts can be transplanted on mice. The grafts were found to connect with local mouse vasculature, lead to invasion of host vessels into the graft, and form an epidermal rete, the epithelial extensions bind to the connective tissue beneath the skin.
“As engineers working to recreate biology, we’ve always appreciated and been aware of the fact that biology is far more complex than the simple systems we make in the lab,” said Pankaj Karande, Profesesor of Chemical and Biological Engineering at Rensselaer and senior author of the study, in a Rensselaer press release. “We were pleasantly surprised to find that, once we start approaching that complexity, biology takes over and starts getting closer and closer to what exists in nature.”
“For those patients [with diabetic or pressure ulcers], these would be perfect, because ulcers usually appear at distinct locations on the body and can be addressed with smaller pieces of skin,” Karande added. “Wound healing typically takes longer in diabetic patients, and this could also help to accelerate that process.”
Here’s a Rensselaer video report about the research:
The publication in journal Tissue Engineering, Part A: 3D bioprinting of a vascularized and perfusable skin graft using human keratinocytes