A group of scientists have made a groundbreaking discovery that could revolutionize reconstructive surgery and hair growth therapies. They found that fat tissue can be used in 3D printing to create multi-layered living skin and even hair follicles. By using fat cells and support structures from human tissue, they were able to successfully repair injured skin in rats. This discovery has the potential to greatly impact facial reconstructive surgery and hair growth treatments for humans.
The team's research was recently published in Bioactive Materials and they have also been granted a patent for their bioprinting technology by the U.S. Patent and Trademark Office.
While thin layers of skin have been previously bioprinted, Ozbolat and his team are the first to successfully print a full, living system of multiple skin layers, including the hypodermis, which is the bottom-most layer. This process can be done intraoperatively, meaning it can be done during surgery, making it a more immediate and seamless option for repairing damaged skin. The top layer, or epidermis, is able to form on its own with support from the middle layer, so it does not need to be printed. The hypodermis, which is made of fat and connective tissue, provides structure and support over the skull.
Ozbolat explained that the hypodermis is crucial in the process of transforming stem cells into fat, which is necessary for wound healing and hair follicle cycling. The researchers used human adipose tissue obtained from patients at Penn State Health Milton S. Hershey Medical Center to extract the extracellular matrix, which is a network of molecules and proteins that provides structure and stability to the tissue. This was used as one component of the bioink. They also obtained stem cells, which can differentiate into different cell types, from the adipose tissue to make another component of the bioink. These components were loaded into a bioprinter's three compartments, along with a clotting solution to help the other components bind onto the injured site.
According to Ozbolat, the three compartments allowed them to precisely print the matrix-fibrinogen mixture and stem cells onto the injury site to form the hypodermis. This layer is essential for wound healing, hair follicle generation, temperature regulation, and other vital processes. The team successfully printed both the hypodermis and dermis layers, with the epidermis forming within two weeks on its own.
The researchers also discovered that the hypodermis contained downgrowths, which is the first stage of hair follicle formation. While fat cells do not directly contribute to the cellular structure of hair follicles, they play a role in regulating and maintaining them. Ozbolat believes that the fat cells may have altered the extracellular matrix to be more supportive of downgrowth formation. The team is now working on advancing this technology to create hair follicles with controlled density, directionality, and growth.
Ozbolat also believes that this technology can be applied in dermatology, hair transplants, and plastic and reconstructive surgeries. It may result in a more natural and aesthetically pleasing outcome for patients. He added that with the fully automated bioprinting ability and compatible materials at the clinical grade, this technology could significantly impact the clinical translation of precisely reconstructed skin. This research, combined with other projects from Ozbolat's lab, such as printing bone and matching pigmentation across different skin tones, offers a hopeful path forward in the field of reconstructive surgery.