Researchers 3D Engineer Complex Skin Graft for Extensive Skin Injury

In an article published in Science Advances earlier this year, researchers from Columbia University detailed the process of developing and testing 3D-engineered complex skin grafts in the shape of human body parts. These grafts were designed to find an alternative to standard flat cultured grafts for extensive skin injuries.

“Despite the advancements in skin bioengineering, 3D skin constructs are still produced as flat tissues with open edges, disregarding the fully enclosed geometry of human skin,” stated the researchers in the study.

With this complexity in mind, Hasan Erbil Abaci, PhD, lead researcher on this study, and his team began creating and developing these complex models by generating a computerized human hand design using a laser scan. The automated scan of the model was then transformed into a hollow scaffold design. The researchers note that they opted for a hand because of this body part's complex shape and intricacies.

The hollow scaffold was bioprinted with ports allowing the researchers to inject substances at specific points of the skin development process. The first step of the process required researchers to cast the outside of the model in a mixture of human primary fibroblasts (FBs) and collagen to create the dermis.

Two weeks later, the researchers injected human primary keratinocytes (KCs) in the space between the dermis and the mold. The mold was then rocked for optimal KC distribution while placed in a cell culture incubator for four hours.

The final step was to remove the skin from the mold and submerge it in an epidermalization solution for seven days. According to a report by the NIH, after developing this skin graft, the researchers compared it with other traditional skin grafts, finding better resistance to stress and more mature proteins in the 3D graft.

Beyond comparing it to standard grafting techniques, the researchers also determined that it could be used practically by testing it on an animal model. The mice in the model were quickly treated and healed within one month.

Skin grafting was practiced as early as 1500 BC; however, the NIH news release on this study acknowledged that engineered skin grafts were developed in the 1980s to treat burns and other skin injuries. Advancements in skin grafting have improved patient outcomes and made the procedure more tolerable. While additional research needs to be done on these complex models, if they are successful, they may revolutionize skin grafting yet again.

“Further research is needed to enhance the cellular complexity of the wearable constructs with skin appendages, pigmentation, and — in the case of in vitro studies — a functional immune system. Despite these current limitations, we believe that the technology described here will greatly advance the field of skin bioengineering and has the potential to be a milestone in tissue engineering of soft tissues,” concluded Abaci and his colleagues in the study.